The characteristics of tumor cells of primary vitreoretinal lymphoma (PVRL) have not been defined, although researches have shown that most cases are of diffuse large B-cell lymphoma (DLBCL). To determine the subtype and biological characteristics of tumor cells of PVRL, we performed a gene expression profiling analysis. RNA was extracted from the vitreous fluid of seven PVRL patients and from nodal samples of ten DLBCL patients; six of germinal center B-cell (GCB) type and four of activated B-cell (ABC) type determined by Hans' criteria. Six PVRL samples showed gene expression profiles which were similar to each other. The patterns were different from those of the ABC-type nodular DLBCL but relatively close to those of the GCB-type nodular DLBCL. Interestingly, all of the six examined PVRL samples had either MYD88^L265P or mutation in the immunoreceptor tyrosine-based activation motif (ITAM) region of CD79B. Five PVRL patients with similar gene expression profiles were treated with a standardized regimen: a set of intravitreal administration of methotrexate (MTX) followed by six courses of systemic high dose of MTX. As a result, two patients had CD79B mutations and showed early central nervous system (CNS) progression. Patients without CNS progression did not have this mutation. In conclusion, PVRL had unique genetic features: an expression pattern different from ABC-type and relatively close to GCB-type DLBCL. CD79B mutations showed a potential to serve as prognostic markers for CNS progression.

Plasmablastic lymphoma mutational profile is undescribed. Here we performed a targeted exonic NGS analysis of 30 plasmablastic lymphoma cases with a B cell lymphoma dedicated panel and FISH for the detection of MYC rearrangements. A complete phenotyping of the neoplastic and microenvironment cell populations was also performed. We have identified an enrichment in recurrent genetic events in MYC (69% with MYC translocation or amplification and 3 cases with missense point mutations), PRDM1/Blimp1 and STAT3 mutations. These gene mutations were more frequent in EBV positive disease. Other genetic events included mutations in BRAF, EP300, BCR (CD79A and CD79B), NOTCH pathway (NOTCH2, NOTCH1 and SGK1) and MYD88pL265P. Immunohistochemical analysis showed consistent MYC expression, higher in cases with MYC rearrangements together with phospho-STAT3 (Tyr705) overexpression in cases with STAT3 SH2 domain mutations. Microenvironment populations were heterogeneous and unrelated with EBV, with an enrichment of Tumor Associated Macrophages (TAM) and PD1 positive T cells. PD-L1 was expressed in all cases in the TAM population but only in 5 cases in the neoplastic cells (4 out of 14 EBV positive cases). HLA expression was absent in the majority of PBL cases. In summary, Plasmablastic lymphoma mutational profile is heterogeneous and related with EBV infection. Genetic events in MYC, STAT3 and PRDM1/Blimp1 are more frequent in EBV positive disease. An enrichment in TAM and PD1 reactive T lymphocytes is found in the microenvironment of PBL cases, that express PD-L1 in the neoplastic cells in a fraction of cases.

We sought to define the genomic landscape of diffuse large B-cell lymphoma (DLBCL) by using formalin-fixed paraffin-embedded (FFPE) biopsy specimens. We used targeted sequencing of genes altered in hematologic malignancies, including DNA coding sequence for 405 genes, noncoding sequence for 31 genes, and RNA coding sequence for 265 genes (FoundationOne-Heme). Short variants, rearrangements, and copy number alterations were determined. We studied 198 samples (114 de novo, 58 previously treated, and 26 large-cell transformation from follicular lymphoma). Median number of GAs per case was 6, with 97% of patients harboring at least one alteration. Recurrent GAs were detected in genes with established roles in DLBCL pathogenesis (e.g. MYD88, CREBBP, CD79B, EZH2), as well as notable differences compared to prior studies such as inactivating mutations in TET2 (5%). Less common GAs identified potential targets for approved or investigational therapies, including BRAF, CD274 (PD-L1), IDH2, and JAK1/2. TP53 mutations were more frequently observed in relapsed/refractory DLBCL, and predicted for lack of response to first-line chemotherapy, identifying a subset of patients that could be prioritized for novel therapies. Overall, 90% (n = 169) of the patients harbored a GA which could be explored for therapeutic intervention, with 54% (n = 107) harboring more than one putative target.

This study is to retrospectively evaluate the prevalence of MYD88 and CD79B mutations and the clinicopathologic characteristics of patients with primary diffuse large B cell lymphoma (DLBCL) of the female genital tract and breast. The characteristics, treatments, and outcomes of 19 patients diagnosed with primary DLBCL of the female genital tract and breast, who had formalin-fixed and paraffin-embedded tissues obtained from diagnostic samples diagnosed between January 2004 and June 2016, were analyzed retrospectively. Nineteen female patients (7 with primary breast and 12 with primary female genital tract DLBCL) were included in this retrospective study. Eleven patients (57.9%) carried a MYD88 mutation, including 10 with MYD8 L265P and 1 with the MYD88 L265S mutation. Seven patients (36.8%) harbored a CD79B mutation, which included two cases with CD79B Y196H, two cases with CD79B Y196N, one case with CD79B Y196D, one case with CD79B Y196F, and one case with CD79B Y196X. Four cases had both MYD88 and CD79B mutations. The clinicopathologic parameters, progression-free survival (PFS), and overall survival (OS) of the MYD88 mutation-carrying group were not significantly different from those of the MYD88 wild-type group except for higher LDH levels. Six patients received cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP), while 13 patients received rituximab plus CHOP, and 13 patients received central nervous system prophylaxis. The median OS and PFS were 73 and 56 months, respectively. Patients with primary breast and primary female genital tract DLBCL have a high frequency of MYD88 and CD79B mutations. The presence of these mutations does not affect survival but may offer additional therapeutic options.

Transformation of Waldenström's macroglobulinemia (WM) to diffuse large B-cell lymphoma (DLBCL) occurs in up to 10% of patients and is associated with an adverse outcome. Here we performed the first whole-exome sequencing study of WM patients who evolved to DLBCL and report the genetic alterations that may drive this process. Our results demonstrate that transformation depends on the frequency and specificity of acquired variants, rather than on the duration of its evolution. We did not find a common pattern of mutations at diagnosis or transformation; however, there were certain abnormalities that were present in a high proportion of clonal tumor cells and conserved during this transition, suggesting that they have a key role as early drivers. In addition, recurrent mutations gained in some genes at transformation (for example, PIM1, FRYL and HNF1B) represent cooperating events in the selection of the clones responsible for disease progression. Detailed comparison reveals the gene abnormalities at diagnosis and transformation to be consistent with a branching model of evolution. Finally, the frequent mutation observed in the CD79B gene in this specific subset of patients implies that it is a potential biomarker predicting transformation in WM.

BACKGROUND

Collagen-induced arthritis (CIA) in mice is a commonly used experimental model for rheumatoid arthritis (RA). We have previously identified a significant quantitative trait locus denoted Cia40 on chromosome 11 that affects CIA in older female mice. This locus colocalizes with another locus, denoted Pregq2, known to affect reproductive success. The present study was performed to evaluate the role of the Cia40 locus in congenic B10.Q mice and to identify possible polymorphic candidate genes, which may also be relevant in the context of RA.

METHODS

Congenic B10.Q mice carrying an NFR/N fragment surrounding the Cia40/Pregq2 loci were created by 10 generations of backcrossing (N10). The congenic mice were investigated in the CIA model, and the incidence and severity of arthritis as well as the serum levels of anti-collagen II (CII) antibodies were recorded.

RESULTS

Significant effects on onset, incidence, severity, and anti-CII antibody titers were observed in female mice carrying a heterozygous congenic Cia40/Pregq2 fragment of NFR/N origin, containing one or more polymorphic genes. Congenic male mice did not show increased incidence of CIA, but males carrying a heterozygous fragment showed a significant increase in severity in comparison with wildtype B10.Q males (littermates).

CONCLUSIONS

The Cia40/Pregq2 locus at chromosome 11 contains one or more polymorphic genes of NFR/N origin that significantly influence both incidence and severity of CIA in heterozygous congenic mice of the B10.Q strain. The major polymorphic candidate genes for the effects on CIA are Cd79b, Abca8a, and Map2k6. The congenic fragment also contains polymorphic genes that affect reproductive behavior and reproductive success. The Sox9 gene, known to influence sex reversal, is a candidate gene for the reproductive phenotype.

Primary testicular lymphoma (PTL), often appearing as focal masses in the scrotum and epididymides, is the most frequent testicular tumor in aged men. Although MYD88 and CD79B mutations were the most common genetic alterations observed, the gene mutation landscape of PTL remains poorly defined. In this study, we identified 1326 mutations involving 311 genes or regions in 90 PTL patients through next-generation sequencing (NGS). PTL patients with the TBL1XR1 mutation, irrespective of treatment therapy, had an inferior overall survival (OS) than TBL1XR1 WT (wild type) patients (p = 0.045). Moreover, patients with this mutation, treated with a CHOP regimen (CTX 750 mg/m² iv, d1,8 ADM 50 mg/m² iv, d1 VCR 1.4 mg/m² iv, d1 PDN 100 mg/m² po d1-5), had a poorer OS (p = 0.019). In addition, such patients were prone to have a more intensive infiltration of tumors (p = 0.025, x² = 4.890). Thus, we speculated that patients with a TBL1XR1 mutation have poorer prognosis, partly due to greater invasion and infiltration of tumors. Our results suggest that the TBL1XR1 mutation can be used as an indicator to predict the prognosis of PTL and can be employed as a promising new target for treatment of PTL in the future.

Primary breast lymphoma is a rare form of extra-nodal lymphoid neoplasm. The most common histological type is the diffuse large B-cell lymphoma, which represents 60-80% of all the cases. Our study analyzes the mutational profile of the primary lymphoma of the breast through targeted massive sequencing with a panel of 38 genes in a group of 17 patients with primary breast diffuse large B-cell lymphoma. Seventy-point-five percent of the patients presented with stage IE and 29.5% with stage IIE. 44% of the cases correspond to lymphomas with germinal center phenotype and 33.3% to activated B-cell. The genes with a higher mutational frequency include PIM1 (in 50% of the analyzed samples), MYD88 (39%), CD79B, PRDM1 and CARD11 (17%), KMT2D, TNFIAP3 and CREBBP (11%). The profile of mutant genes involves mostly the NFκB signaling pathway. The high frequency of mutations in PIM1 compared with other lymphomas may have implications in the clinical presentation and evolution of this type of lymphoma.

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is a rare subtype of extranodal DLBCL. Because of the rarity of this disease, its morphologic and genetic features are not comprehensively studied. Here, we systematically reviewed the clinicopathologic features of 42 cases of PA-DLBCL from our institution and investigated the frequency of MYD88 L265P and CD79B (exon 5) mutation in 29 eligible cases using Sanger sequencing. Clinically, PA-DLBCL was predominant in elderly male patients with advanced clinical stage and poor outcomes. Morphologically, the tumors often showed a sinusoidal and/or cohesive pattern with condensed chromatin and inconspicuous nucleolus which mimicked neuroendocrine carcinoma. Moreover, increased Reed-Sternberg-like cells were observed frequently. These confounding morphologic manifestations may lead to misdiagnosis. Genetically, PA-DLBCL harbored a high prevalence of MYD88 L265P (24%) and CD79B mutations (52%) which may be involved in lymphomagenesis. The CD79B mutation was significantly associated with a worse prognosis. A novel Histo-Molecular Classification system (4 categories) was proposed based on correlation with genetic changes. Generally, the neuroendocrine carcinoma-like type was associated with CD79B mutation, whereas the RS-like cell type indicated MYD88 L265P. The biphasic type was correlated with coexisting mutations of MYD88 and CD79B, whereas the common type implied no mutation. Furthermore, the common type showed significantly better survival. In conclusion, the proposed new category system could indicate the genetic changes as well as facilitate risk stratification to guide treatment and predict prognosis. Although this study augmented our understanding of PA-DLBCL, further analysis is required to validate our results and extend them to extranodal DLBCL at other sites.

The objective of this study was to evaluate immunophenotypic profile along with clinical follow-up in patients with advanced stage mantle cell lymphoma (MCL), and their possible influence on overall survival (OS). Bone marrow (BM) cell and/or peripheral blood mononuclear cell flow cytometric analyses of the following antigens were performed: HLA-DR, CD19, CD20, CD22, CD23, CD25, CD10, SmIg, kappa, lambda, CD79b, CD38, FMC7, CD3, CD2, and CD5. There were 14 patients in IV CS, and 26 patients in CS V. All patients were treated with CHOP. Immunological markers showed a typical phenotype (CD5+ CD23-, Cyclin D1) in all cases. Pathohistological type of BM infiltration was predominantly diffuse (72.5%), and in remainder of patients, nodular. Comparison of patients with leukemic phase of MCL with CSIV (BM), has shown significantly higher expression of CD19, CD20, and CD23, followed by permanently negative expression of CD23. Patients with blastic variant of MCL had higher expression of CD23, compared to typical MCL (P < 0.001). Median OS was 20 months, and there were no significant OS-differences between CS IV and leukemic phase patients. Survival analyses showed that negative prognostic influence had high IPI (P < 0.01), presence of extranodal localization (P < 0.01), and diffuse type of BM involvement (P < 0.01). Using Cox regression according to OS, IPI had independent prognostic value (P < 0.001). Our results demonstrated that in the advanced MCL patients the most powerful prognostic factor was IPI, while extranodal localization and type of BM infiltration were of a limited value.

Multiparametric clinical flow cytometry has evolved from two-parameter quantitative assessment of lymphocytes to assessment of many qualitative parameters of suspensions obtained from bone marrow, peripheral blood, and lymph nodes for hematopathology. Nowadays, lymphoma immunophenotyping is a necessary complement to morphology and molecular parameters in the diagnosis and monitoring of human hematopoietic malignancies. The aim of the present study was to determine whether immunophenotypic differences could be used to distinguish between non-Hodgkin's B cell lymphoma (NHL-B) and the normal B cell subpopulation by assessing the variability in the patterns of expression of some lymphoid antigens (CD5, CD19, FMC7, CD23, CD20, CD79b, CD38, CD22, CD10, sIgkappa, sIglambda, mIgA, mIgG, mIgM, and mIgD) in specimens obtained from patients with NHL-B. We have studied peripheral blood samples, lymph node suspensions, and bone marrow specimens from 20 patients with malignant lymphoma and from controls without oncohematologic disease. Some patients showed stable patterns of antigen expression that remained unchanged over time and were consistent from one specimen to another. Other patients showed more variability in the pattern of antigen expression from different specimens. The two-way cluster analysis of antigens revealed three patterns of expression: (1) most cells in most cases positive (CD5, CD19, CD20, CD23, CD45); (2) most cells in most cases negative (CD10, mIgG, CD22, CD23,CD38); and (3) a mixed pattern with a variable number of positive cases and a variable percentage of positive cells in individual cases (CD22, CD38, CD79b, FMC7, mIgD, mIgM, mIgA, mIgG, sIgkappa, sIglambda). The expression of several antigens was strongly interdependent, even when antigens belonged to entirely different gene families. Such antigen pairs were CD19/CD45; CD19/CD79b; CD23/Igkappa; and CD45/CD79b. Our results suggest that different factors may determine the stability or the variability of such multiantigen expression, particularly the biology and function of the different antigens and the mechanisms of disease dissemination and progression.

There is an urgent need to identify more accurate prognostic biomarkers in melanoma patients, particularly in those with metastatic disease. This study aimed to identify melanoma and leukocyte surface antigens predictive of survival in a prospective series of AJCC stage IIIb/c melanoma patients (n = 29). Live cell suspensions were prepared from melanoma metastases within lymph nodes (LN). The suspensions were immuno-magnetically separated into CD45(+) (leukocyte) and CD45(-) (non-hematopoietic, enriched melanoma cell) fractions. Surface antigens on CD45(-) and CD45(+) cell populations were profiled using DotScan™ microarrays (Medsaic Pty. Ltd.) and showed differential abundance levels for 52 and 78 antigens respectively. Associations of the surface profiles with clinicopathologic and outcome data (median follow-up 35.4 months post LN resection) were sought using univariate (log-rank test) and multivariate (Wald's test; modelled with patient's age, gender and AJCC staging at LN recurrence) survival models. CD9 (p = 0.036), CD39 (p = 0.004) and CD55 (p = 0.005) on CD45(+) leukocytes were independently associated with distant metastasis-free survival using multivariate analysis. Leukocytes with high CD39 levels were also significantly associated with increased overall survival (OS) in multivariate analysis (p = 0.016). LNs containing leukocytes expressing CD11b (p = 0.025), CD49d (p = 0.043) and CD79b (p = 0.044) were associated with reduced OS on univariate analysis. For enriched melanoma cells (CD45(-) cell populations), 11 surface antigens were significantly correlated with the disease-free interval (DFI) between diagnosis of culprit primary melanoma and LN metastasis resection. Nine antigens on CD45(+) leukocytes also correlated with DFI. Following validation in independent datasets, surface markers identified here should enable more accurate determination of prognosis in stage III melanoma patients and provide better risk stratification of patients entering clinical trials.

The antibody-drug conjugate polatuzumab vedotin has been approved to treat relapsed or refractory diffuse large B-cell lymphoma. The drug recognizes the CD79b protein on B cells and kills them with a molecule that prevents tubulin polymerization.

BACKGROUND

Gene rearrangements and specific translocations define some B-cell non-Hodgkin lymphoma (NHL) subtypes. Genome-wide mutational studies have revealed recurrent point mutations with prognostic implications. The goals of this study were to evaluate the feasibility of applying a multiplex mutation assay to archival cytospin preparations (CPs) and to investigate the rate of EZH2, CD79B, and MYD88 mutations in B-cell NHL samples previously tested for MYC rearrangement and/or IGH/BCL-2 translocation.

METHODS

DNA was extracted from archival CPs of B-cell NHL cases with previous fluorescence in situ hybridization (FISH) assays for MYC rearrangement and/or IGH/BCL-2 translocation. Multiplex sequencing was performed for the detection of EZH2 (Y641), CD79B (Y196), and MYD88 (L265) mutations. Sanger sequencing was applied to samples with positive results and failed assays.

RESULTS

Eighty-eight archival CPs were available from 40 patients. Alterations detected by FISH were: MYC rearrangement (10 cases), IGH/BCL-2 translocations (21 cases), dual translocations (6 cases), and other abnormalities for IGH/BCL-2 (23 cases) and for MYC (16 cases). DNA concentration ranged from 1.88 to 62.85 ng/µL (mean, 9.46 ng/µL). Successful results were obtained in 88.0% of the specimens submitted to multiplex sequencing. With Sanger sequencing, 2 additional mutated cases were found, and all cases with mutations were confirmed. Eight specimens showed mutations: 6 for EZH2, 1 for CD79B, and 1 for MYD88. Among them, 5 cases showed concurrent MYC and/or IGH/BCL-2 translocations and 2 revealed abnormal signals of IGH/BCL-2 and MYC.

CONCLUSIONS

CPs archived for up to 6 years are a reliable source of high-quality genomic material for multiplex sequencing. Almost all B-cell NHL with point mutations showed concurrent chromosomal abnormalities.

Antigen-dependent activation of B lymphocytes is mediated through surface immunoglobulins and their associated molecules Ig-alpha (CD79a, Mb1) and Ig-beta (CD79b, B29). Here we show that an antibody directed against the extracellular part of human Ig-beta can, when cross-linked by CD32-transfected L cells, induce an IL-2-dependent proliferation of tonsil B cells. With the use of L cells stably transfected with both CD32 and CD40L, anti-Ig-beta activation of B cells was combined with CD40 triggering, an important component of the T cell-dependent B cell activation. This dual cellular activation resulted in two different phases, with initially synergistic proliferative effects, both without and with IL-2 or IL-10. Then, after 5-6 days of culture, cells stimulated with both anti-Ig-beta and CD40L underwent massive cell death, in contrast to B cells activated with CD40L alone. Cell death was not prevented by the addition of IL-2 or IL-10, but was prevented by the addition of IL-4. These results are discussed in the context of positive and negative selection of mature B cells.

Leucocyte populations in the sinonasal mucosa of cats with and without upper respiratory tract aspergillosis were compared using immunohistochemistry and computer-aided morphometry. Inflammation was identified in the nasal mucosa of all affected cats, comprising predominantly of lymphoplasmacytic infiltration of the lamina propria associated with epithelial proliferation and degeneration. There was intense and diffuse expression of class II antigens of the major histocompatibility complex, associated with sites of hyphal invasion with hyperplasia and ulceration of the epithelium adjacent to fungal elements. Significantly more CD79b(+) cells, total lymphocytes, immunoglobulin (Ig)-expressing cells and MAC387(+) cells infiltrated the epithelium and more IgG(+) cells and total Ig-expressing cells infiltrated the lamina propria in affected cats compared with controls. Importantly, the inflammatory profile in affected cats was not consistent with the T helper (Th)1 and Th17 cell-mediated response that confers protective acquired immunity against invasive aspergillosis in dogs and people and in murine models of the infection. This finding may help to explain the development of invasive aspergillosis in systemically immunocompetent cats.

CD5-positive (CD5+ ) diffuse large B-cell lymphoma (DLBCL) is characterized by frequent central nervous system recurrence and a predominant activated B-cell-like nature. Primary DLBCL in sanctuary sites (DLBCL-SS) also demonstrates these features, and >70% of patients harbor myeloid differentiation primary response 88 (MYD88) (L265P) and CD79B mutations. The objective of the current study was to elucidate a possible relationship between CD5+ DLBCL and DLBCL-SS.

MYD88, CD79B, CD79A, and caspase recruitment domain family member 11 (CARD11) mutations were examined in samples from 40 patients with CD5+ DLBCL. Mutation analysis was performed by direct sequencing.

MYD88 and CD79B mutations were detected in 33% (13 patients) and 38% (15 patients), respectively, of the 40 patients with CD5+ DLBCL. Ten patients had these 2 gene mutations, and 1 had a CD79A mutation. One of 2 patients with testicular involvement had both MYD88 and CD79B mutations. The other patient had a MYD88 mutation alone. None of the 31 patients examined was found to have a CARD11 mutation. MYD88 and CD79B mutations were found to be associated with localized disease (P = .038 and P = .003, respectively). Primary extranodal lymphoma was associated with higher frequencies of mutations in MYD88 or both MYD88 and CD79B (P = .008 and P = .014, respectively). There was no significant difference in overall survival based on MYD88 and CD79B mutation status.

The incidence of MYD88 and CD79B mutations in patients with CD5+ DLBCL is lower than that in patients with DLBCL-SS, suggesting that CD5+ DLBCL is not the same disease as DLBCL-SS in terms of gene mutation status. CARD11 mutations are rare in patients with CD5+ DLBCL. Cancer 2017;123:1166-1173. © 2016 American Cancer Society.

BACKGROUND

CD79b is a relatively newly characterized B-cell marker that is expressed in a minority of chronic lymphocytic leukemia (CLL) cases.

OBJECTIVE

To systematically correlate CD79b expression with specific morphologic and immunophenotypic findings and trisomy 12.

METHODS

We assessed CD79b expression in 100 consecutively accrued CLL cases that were also analyzed by conventional cytogenetics. Based on the association between trisomy 12 and CD79b expression, we then assessed 43 additional CLL cases with trisomy 12. CD79b expression was correlated with morphology and expression of other immunophenotypic markers.

RESULTS

Eighteen (18%) of 100 consecutively accrued cases were CD79b positive. No significant association was found between CD79b expression and atypical morphology. CD79b expression correlated with CD22 and FMC7 positivity. Eight (8%) cases had trisomy 12; 4 (50%) of these were CD79b positive, suggesting an association with trisomy 12. Examination of a second group of 51 CLL cases with trisomy 12 (including 8 cases from the initial study group) showed that CD79b was positive in 26 cases (49%), a frequency significantly higher than that of the consecutively accrued CLL cases without trisomy 12 (P <.05).

CONCLUSIONS

We conclude that CD79b immunoreactivity is positive in approximately 20% of CLL cases and that expression correlates with trisomy 12 and atypical immunophenotypic findings.

BACKGROUND

Blasts from B acute lymphoblastic leukemia (B-ALL) may express CD56 in about 10% of cases. The presence of this marker at diagnosis is associated with an increased risk of meningeal relapse. A case is described of B-ALL which was CD56 negative at diagnosis, and expressed this marker when isolated meningeal relapse was diagnosed.

METHODS

A 53-year-old female patient presented with neurological symptoms during maintenance therapy for B-ALL. Peripheral blood, bone marrow, and cerebrospinal fluid (CSF) were subjected to both morphological and flow cytometric analyses. The latter was carried out by a wide routine panel of MoAbs which was the same as the one at diagnosis and included CD56. Isolated meningeal relapse was diagnosed since blast cell infiltration was detected in the CSF, but not in the peripheral blood and bone marrow samples. Blast cells showed an immunological phenotype similar to that at diagnosis (cyCD79a+, CD79b+, CD19+, CD22+, CD34+, CD10+, CD20+), but characterized by the acquisition of CD56 on the surfaces of more than 90% of cells.

CONCLUSIONS

This case shows that CD56 can be expressed at relapse of B-ALL and that its presence likely enables leukemic cell binding to the central nervous system (CNS). This phenomenon may be responsible for the isolated CNS relapse diagnosed in this patient.

Chronic Lymphocytic Leukemia (CLL) is one of the most common diagnoses made by flow cytometry laboratories. There is no consensus on which markers need to be used in flow cytometry for accurate immunophenotyping. Herein, we investigated the role of markers used in flow cytometry in the distinction between CLL and MCL.

A total 339 recently diagnosed B lymphoproliferative patient cases were retrospectively studied for their immunophenotypical propoerties using flow cytometry. They included 306 CCL cases and 33 MCL cases.

The positivity of CD23 was diagnostic for CLL (p < 0.001). CD22, CD79b, and FMC7 expressions were highly positive in CLL cases, but not statistically significant in making differential diagnoses between atypical CLL and MCL (p = 1.000, p = 0.431 and p = 1.000, respectively). Evaluation of CD11c, CD25, CD43, and CD38 expressions, which are included in the LPD panel but not in the matatutes scoring, revealed that CD11c, CD38, and CD43 expressions are statistically significant in the distinction of atypical CLL from MCL (p < 0.001, p < 0.001, and p < 0.001).

We can say that CD11c, CD38, and CD43, which have been included in our lymphoproliferative disease panel, were more valuable than CD22, CD79b, and FMC7 in the diagnosis of CLL.

Six cases of non-Hodgkin B-cell lymphoma that mimicked either chronic lymphocytic leukemia (CLL) or a CLL variant at presentation are reported. The patients ranged from 54 to 89 years and included three females and three males. All six patients had prominent peripheral blood lymphocytosis at presentation; the initial morphologic impression was CLL in three cases, CLL/prolymphocytic leukemia (PLL) in two cases, and PLL in one. Five patients had bone marrow biopsies; each showed a lymphoid infiltrate in a focally random, interstitial, and/or diffuse pattern. Flow cytometric immunophenotyping showed CD20-positive B cells with surface immunoglobulin (Ig) light chain restriction in all six patients. The five cases resembling CLL or CLL/PLL had at least a subset of CD5-positive B cells, whereas CD5 was absent in the one case that resembled PLL. CD23 was positive in three of the four cases studied that resembled CLL or CLL/PLL; CD79b was positive in three, FMC7 was positive in two, and surface Ig and CD20 were brightly positive in three. A t(11;14) (q13;q32) was found in four cases that resembled CLL or CLL/PLL; they were subsequently diagnosed as mantle cell lymphoma. The remaining two cases mimicking CLL or PLL were diagnosed as lymphomas of follicle center origin with leukemic phase based on the presence of t(14;18) (q32;q21). Thus although the morphology of these six cases resembled CLL or variants, and immunophenotyping by flow cytometry showed overlapping features, genetic studies enabled distinction of these leukemic non-Hodgkin lymphoma from chronic lymphocytic leukemia or variants.

BACKGROUND

Monoclonal B-cell lymphocytosis is classified as 'high-count or clinical' monoclonal B-cell lymphocytosis and 'low-count or population' monoclonal B-cell lymphocytosis. Previously, 167 first-degree relatives pertaining to sporadic (non-familial) chronic lymphocytic leukemia families were studied and the presence of seven monoclonal B-cell lymphocytosis individuals was reported.

OBJECTIVE

The aim of this report is to describe the outcomes of five of the original monoclonal B-cell lymphocytosis individuals.

METHODS

Flow cytometry analysis was performed on mononuclear cells previously isolated from peripheral blood samples. A strategy of sequential gating designed to identify the population of CD19(+)/CD5(+) B-lymphocytes was used and, subsequently, the monoclonal B-cell lymphocytosis cells were characterized by the CD20(weak)/CD79b(weak/negative) phenotype.

RESULTS

The monoclonal B-cell lymphocytosis clone showed consistent stability over time with little variations in size. After a median follow-up of 7.6 years, none of the five monoclonal B-cell lymphocytosis individuals progressed to chronic lymphocytic leukemia or other B-cell lymphoproliferative disease.

CONCLUSIONS

The data of this study suggest that chronic lymphocytic leukemia-like monoclonal B-cell lymphocytosis detected in the context of sporadic chronic lymphocytic leukemia families is not prone to clinical evolution and could be just a sign of immune senescence.