BACKGROUND

Several candidate genes have been found to be associated with the inflammatory response of IgE-mediated allergy, so also the immunoglobulin constant heavy G chain (IGHG) genes. The IGHG genes are situated close to the IGHE gene on chromosome 14q32, 5'mu, delta, gamma3, gamma1, alpha1, gamma2, gamma4, epsilon, alpha2, 3'. They are inherited in a Mendelian fashion and expressed randomly in allelic exclusion. The alternative and functionally different gamma3, gamma1 and gamma2 gene variants are found in four IGHG haplotypes, coding four B cell variants.

OBJECTIVE

The aim of this study was to assess the frequency of different IGHG genes in relation to phenotypes associated with allergy, in a case-control study.

METHODS

We identified the constant heavy-chain genes of IgG in 198 allergic and non-allergic children participating in the Phase II of the International Study of Asthma and Allergy in Children. The IGHG genes were assessed by the alternative serum IgG subclass allotypes expressing the alternative alleles of gamma3, gamma1 and gamma2 genes, using ELISA and double immunodiffusion.

RESULTS

The IGHG*bfn haplotype (=B1 cells) and IGHG2*n allele dominated (51% vs. 24%, P=0.002) and the IGHG*bf-n haplotype (=B2 cells) was infrequent (16% vs. 52%, P < 0.001) in allergic children with a family history of allergy, clinical manifest allergy and positive skin prick test (SPT). The frequency of IGHG genes was similar in children with maternal and paternal heredity and in children with wheezing, eczema or rhinitis, as well as in children with different positive SPT. The IGHG*bfn haplotype with the IGHG2*n allele was strongly associated with heredity for allergy. The IGHG*bf-n haplotype was inversely related to allergy. Conclusions IgG allotypes, immunochemical and functional variants of IgG molecules from IGHG genes are associated with atopy. The IGHG*bfn haplotype (=B1 cells) with the IGHG2*n allele dominates, associated with an increased risk for atopy. In contrast, the IGHG*bf-n haplotype (=B2 cells) with the IGHG2*-n allele is associated with low risk.

Knowledge of epigenetically regulated biomarkers linked to obesity development is still scarce. Improving molecular understanding of the involved factors and pathways would improve obesity phenotype characterization and reveal potentially relevant targets for obesity intervention. The Illumina Infinium HumanMethylation450 BeadChip was used in a leucocyte epigenome-wide association study (EWAS) to quantify differential DNA methylation in 60 lean compared with 60 obese young women. Replication was done in monozygotic twins discordant for obesity. At adolescence and adulthood, the two weight groups differed significantly in obesity-related traits and metabolic risk factors. Differential hypomethylation was overrepresented in obese compared to lean women. In the adjusted model, the EWAS revealed 10 differentially methylated CpG sites linked to 8 gene loci - COX6A1P2/FGD2, SBNO2, TEX41, RPS6KA2, IGHE/IGHG1/IGHD, DMAP1, SOCS3, and SETBP1- and an enhancer locus at chromosome 2 (2p25.1). The sites linked to TEX41, IGHE/IGHG1/IGHD, DMAP1, and SETBP1 were novel findings, while COX6A1P/FGD2, SBNO2, RPS6KA2, and SOCS3 had been identified previously with concordant direction of effects. RPS6KA2, DMAP1, and SETBP1 were replicated in the BMI-discordant monozygotic twin cohort using the FDR of 5%.

Early and late primary IgM antibody responses of mice to Thy-1.1 antigens showed different antigenic and cellular requirements. We studied genetic controls of the early primary responses, which could be induced by subcellular thymocyte antigens independently of host T-cell activity. All Thy-1.2 mouse strains of Igha (BALB/c and BC8), Igh-VaCb (BAB14), Ighd (AKR/Cum), Ighj (CBA/J, C3H/HeN, C3H.SW, and C3H.JK), and Ighn (NZB) definitely responded early to Thy-1.1 antigens from AKR/J (Ighd), A.Thy-1.1 (Ighe), or B10.Thy-1.1 (Ighb) mice or SD rats, whereas all strains of Ighb (C57BL/6, C57BL/10, B10.D2, B10.BR, B10.A, CB20 and CWB), Ighc (DBA/2), Ighe (A/J), and Igho (C.AL20) responded poorly to the same antigens. This contrasts with the observation that both strains of Ighj (C3H/HeN) and Ighb (B10.BR) responded well at later times. As was the case for late responses, the matching of H-2 between donor and recipient resulted in early responses of exceptional quality in high-responder strains. It was concluded that under the influence of H-2, whose incompatibility between donor and recipient partially interferes with responses, early but not late primary Thy-1.1-specific antibody responses are selectively controlled by Igh-V or closely linked Ir gene(s) as a new VH marker.

BACKGROUND

The dissociation between specific IgE and skin prick test reactivity to aeroallergens, a common finding in populations living in low and middle-income countries, has important implications for the diagnosis and treatment of allergic diseases. Few studies have investigated the determinants of this dissociation. In the present study, we explored potential factors explaining this dissociation in children living in an urban area of Northeast Brazil, focusing in particular on factors associated with poor hygiene.

METHODS

Of 1445 children from low income communities, investigated for risk factors of allergies, we studied 481 with specific IgE antibodies to any of Blomia tropicalis, Dermatophagoides pteronyssinus, Periplaneta americana and Blatella germanica allergens. Data on demographic, environmental and social exposures were collected by questionnaire; serum IgG and stool examinations were done to detect current or past infections with viral, bacterial, protozoan and intestinal helminth pathogens. We measured atopy by skin prick testing (SPT) and specific IgE (sIgE) to aerollergens in serum (by ImmunoCAP). SIgE reactivity to B. tropicalis extract depleted of carbohydrates was measured by an in-house ELISA. Total IgE was measured by in house capture ELISA. SNPs were typed using Illumina Omni 2.5.

RESULTS

Negative skin prick tests in the presence of specific IgE antibodies were frequent. Factors independently associated with a reduced frequency of positive skin prick tests were large number of siblings, the presence of IgG to herpes simplex virus, Ascaris lumbricoides and Trichuris trichiura infections, living in neighborhoods with infrequent garbage collection, presence of rodents and cats in the household and sIgE reactivity to glycosylated B. tropicalis allergens. Also, SNP on IGHE (rs61737468) was negatively associated with SPT reactivity.

CONCLUSIONS

A variety of factors were found to be associated with decreased frequency of SPT such as unhygienic living conditions, infections, total IgE, IgE response to glycosylated allergens and genetic polymorphisms, indicating that multiple mechanisms may be involved. Our data, showing that exposures to an unhygienic environment and childhood infections modulate immediate allergen skin test reactivity, provide support for the "hygiene hypothesis".

The requirement for idiotype-specific helper T (Th) cells in the generation of a major intrastrain crossreactive idiotype was investigated. This idiotype, designated CRIA, is associated with a large proportion of anti-p-azobenzenearsonate (anti-Ar) antibodies in A/J mice. Secondary in vitro responses were studied. Using carrier-primed heterogeneous Th-cell populations, it was found that CRIA expression is determined by the mouse strain that provides the responding B cells and is independent of the strain of the Th cells functioning in vitro. Thus, A/J or A.BY (Ighe) B-plus-accessory-cell populations, primed in vivo to keyhole limpet hemocyanin-Ar (KLH-Ar), generated CRIA-dominant responses in vitro in the presence of KLH-Ar regardless of whether the KLH-primed Th cells were derived from CRIA+ strains (A/J or A.BY, Ighe) or CRIA- strains (B10.A or C57BL/10, Ighb). Further, when major histocompatibility complex-restricted, KLH-specific Th-cell clones were used, the CRIA dominance of the Ar-specific responses was again determined by the strain providing B plus accessory cells. Similar levels of expression of CRIA in Ar-specific antibodies were generated in the presence of heterogeneous or cloned Th cells. The results suggest that there is no absolute requirement for idiotype-specific Th cells in generating an Ar-specific secondary antibody response in vitro.

A limited number of deletions and duplications within the human immunoglobulin heavy chain constant locus (IGHC) has previously been reported. We studied the IGHC locus in about 500 individuals representing three major races of human, Negroid (Gambian), Mongoloid (Japanese and Chinese), and Caucasoid (Iranian and Swedish). The haplotype frequency of duplications is highest in the Mongoloid population (22%), followed by the Caucasian (10%) and Negroid (5%) populations. The corresponding frequency of deletions are 2, 1.5, and 3.5%, respectively. New types of multiple duplications were found in this study on different genetic (H haplotype and racial) backgrounds. The most common duplication, found in all populations studied, encompasses the IGHA1-IGHE genes. The only deletion common to all racial groups is an isolated deletion of the IGHG4 gene. Our data are consistent with the hypothesis that the Caucasoid-Mongoloid group diverged from the hominoid ancestor after development of the Negroid populations, with subsequent evolution within the respective groups thereafter.

The knowledge of genetic factors determining the age at onset of diabetes may help to delay the development of diabetes and its complications. This prompted us to use our well-characterized BB/OK rat whose age at onset of diabetes can change from 50 to more than 400 days for crossing studies to search for loci cosegregating with the age at onset. Fifty-nine diabetic first backcross hybrids resulting from crosses between diabetic BB/OK and diabetes-resistant DA and SHR rats were genotyped with PCR-analyzed microsatellite markers located on 21 chromosomes. Loci on chromosomes 6 (Ighe -D6Mgh2) and 8 (D8Mit2- Apoc3) were linked with the age at onset. Hybrids which were homozygous for the BB alleles developed significantly earlier diabetes than hybrids which were heterozygous The difference between the age at onset of heterozygous and homozygous hybrids reached a maximum at the loci Ighe on chromosome 6 (+ 32 days, p = 0.0018) and D8Mit2 on chromosome 8 (+ 28 days, p = 0.007). Candidate genes around the loci linked with the age at onset of diabetes are involved in the humoral and cellular immune response. For the first time, this study provides evidence that genetic factors can affect the age at onset of diabetes in the rat.

Equine insect bite hypersensitivity (IBH) is a seasonal IgE-mediated dermatosis caused by bites of insects of the genus Culicoides. A familial predisposition for the disease has been shown but, except for the MHC, the genes involved have not been identified so far. An immunogenomic analysis of IBH was performed in a model population of Old Kladruby horses, all living in the same environment. Clinical signs of IBH were used as phenotypic manifestation of IBH. Furthermore, total serum IgE levels were determined in the sera of these horses and used as an independent phenotypic marker for the immunogenetic analysis. Single nucleotide polymorphisms (SNPs) in candidate immunity-related genes were used for association analyses. Genotypes composed of two to five genes encoding interferon gamma -IFNG, transforming growth factor beta 1 -TGFB1, Janus kinase 2 -JAK2, thymic stromal lymphopoietin -TSLP, and involucrin -IVL were associated with IBH, indicating a role of the genes in the pathogenesis of IBH. These findings were supported by analysis of gene expression in skin biopsies of 15 affected and 15 unaffected horses. Two markers associated with IBH, IFNG and TGFB1, showed differences in mRNA expression in skin biopsies from IBH-affected and non-affected horses (p<0.05). Expression of the gene coding for the CD14 receptor molecule -CD14 was different in skin biopsies at p<0.06. When total IgE levels were treated as binary traits, genotypes of IGHE, ELA-DRA, and IL10/b were associated with this trait. When treated as a continuous trait, total IgE levels were associated with genes IGHE, FCER1A, IL4, IL4R, IL10, IL1RA, and JAK2. This first report on non-MHC genes associated with IBH in horses is thus supported by differences in expression of genes known to play a role in allergy and immunity.

Three different HindIII/EcoRI restriction fragment alleles of the human immunoglobulin IGHE gene have been detected with a C epsilon probe in the Tunisian population. Two of these alleles can be explained by a Negroid contribution in their gene pool.

BACKGROUND

Diagnostic evaluation of eosinophilic esophagitis (EoE) remains difficult, particularly the assessment of the patient's allergic status.

OBJECTIVE

This study sought to establish an automated medical algorithm to assist in the evaluation of EoE.

METHODS

Machine learning techniques were used to establish a diagnostic probability score for EoE, p(EoE), based on esophageal mRNA transcript patterns from biopsies of patients with EoE, gastroesophageal reflux disease and controls. Dimensionality reduction in the training set established weighted factors, which were confirmed by immunohistochemistry. Following weighted factor analysis, p(EoE) was determined by random forest classification. Accuracy was tested in an external test set, and predictive power was assessed with equivocal patients. Esophageal IgE production was quantified with epsilon germ line (IGHE) transcripts and correlated with serum IgE and the Th2-type mRNA profile to establish an IGHE score for tissue allergy.

RESULTS

In the primary analysis, a 3-class statistical model generated a p(EoE) score based on common characteristics of the inflammatory EoE profile. A p(EoE) ≥ 25 successfully identified EoE with high accuracy (sensitivity: 90.9%, specificity: 93.2%, area under the curve: 0.985) and improved diagnosis of equivocal cases by 84.6%. The p(EoE) changed in response to therapy. A secondary analysis loop in EoE patients defined an IGHE score of ≥37.5 for a patient subpopulation with increased esophageal allergic inflammation.

CONCLUSIONS

The development of intelligent data analysis from a machine learning perspective provides exciting opportunities to improve diagnostic precision and improve patient care in EoE. The p(EoE) and the IGHE score are steps toward the development of decision trees to define EoE subpopulations and, consequently, will facilitate individualized therapy.

The extent and composition of the immune response in a breast cancer is one important prognostic factor for the disease. The aim of the current work was to refine the analysis of the humoral component of an immune response in breast tumors by quantifying mRNA expression of different immunoglobulin classes and study their association with prognosis. We used RNA-Seq data from two local population-based breast cancer cohorts to determine the expression of IGJ and immunoglobulin heavy (IGH) chain-encoding RNAs. The association with prognosis was investigated and public data sets were used to corroborate the findings. Except for IGHE and IGHD, mRNAs encoding heavy chains were generally detected at substantial levels and correlated with other immune-related genes. High IGHG1 mRNA was associated with factors related to poor prognosis such as estrogen receptor negativity, HER2 amplification, and high grade, whereas high IGHA2 mRNA levels were primarily associated with lower age at diagnosis. High IGHA2 and IGJ mRNA levels were associated with a more favorable prognosis both in univariable and multivariable Cox models. When adjusting for other prognostic factors, high IGHG1 mRNA levels were positively associated with improved prognosis. To our knowledge, these results are the first to demonstrate that expression of individual Ig class types has prognostic implications in breast cancer.

Keywords: Breast cancer; Prognostic markers; Tumour immunology.

The constant region of the human immunoglobulin heavy chain (IGHC) is encoded by a cluster of genes near the telomere of chromosome 14q. Deletions and duplications of single or multiple genes in the cluster have been identified, but little information about the breakpoint junctions has been available, in part due to the high degree of sequence similarity between the genes in this region. We report an intensive study of a homozygous deletion, using Southern hybridization and polymerase chain reaction techniques. We found that the deleted DNA includes the functional epsilon gene, and that the breakpoints are located within a 2 kilobase Bam HI/Sac I region of both the IGHEP1 and IGHE genes. These results revise a previous conclusion regarding the deleted region. Definition of breakpoints occurring within this cluster may shed light on recombination mechanisms.

Recently, immunoglobulin (Ig) expression was reported in a variety of non-B lineage cells, including myeloid cells. We assessed whether hematopoietic stem/progenitor cells (HSC/HPCs) can express Ig. With Gene Expression Omnibus (GEO) microarray database analysis, we found that IGHM was expressed with the highest frequency and level in umbilical cord blood CD34(+) HSC/HPCs, followed by IGK@, IGHE, IGHD, IGHG1, and IGHA1, while IGL@ was nearly not expressed. Ig expression was further confirmed by molecular experiments and immunofluorescence. Moreover, HSC/HPCs-derived Ig displayed restricted/biased usages and VHDJH rearrangement patterns. These results suggest that Igs, especially IgM, may have a role in CD34(+) HSC/HPCs function.

The extent and composition of the immune response in a breast cancer is one important prognostic factor for the disease. The aim of the current work was to refine the analysis of the humoral component of an immune response in breast tumors by quantifying mRNA expression of different immunoglobulin classes and study their association with prognosis. We used RNA-Seq data from two local population-based breast cancer cohorts to determine the expression of IGJ and immunoglobulin heavy (IGH) chain-encoding RNAs. The association with prognosis was investigated and public data sets were used to corroborate the findings. Except for IGHE and IGHD, mRNAs encoding heavy chains were generally detected at substantial levels and correlated with other immune-related genes. High IGHG1 mRNA was associated with factors related to poor prognosis such as estrogen receptor negativity, HER2 amplification, and high grade, whereas high IGHA2 mRNA levels were primarily associated with lower age at diagnosis. High IGHA2 and IGJ mRNA levels were associated with a more favorable prognosis both in univariable and multivariable Cox models. When adjusting for other prognostic factors, high IGHG1 mRNA levels were positively associated with improved prognosis. To our knowledge, these results are the first to demonstrate that expression of individual Ig class types has prognostic implications in breast cancer.

IgE is a key effector molecule in atopic diseases; however, the regulation mechanisms of IgE production in IgE B cells remain poorly understood. In the present study, we demonstrate that JSI-124 (cucurbitacin I), a selective STAT3 inhibitor, selectively inhibits production of IgE by a human IgE B cell line, CRL-8033 cells, while does not affect the IgG production by IgG B cell lines. In the aspect of molecular mechanism, we found that Igλ, but not Ighe, gene expression was suppressed by JSI-124. The above effects of JSI-124 were not mediated by affecting cellular proliferation or apoptosis. Furthermore, multiple B cell differentiation-related genes expression was not significantly affected by JSI-124. Taken together, we demonstrate a potential strategy of therapeutically suppressing IgE production without affecting IgG production in atopic patients.

We have previously demonstrated the relationship between antigens on BALB/c methylcholanthrene (MC)-induced fibrosarcomas and T cell regulatory molecules by using a variety of antisera raised to these sarcomas in BALB/c and BALB/c X C57BL/6 (CB6F1) mice. One such pool of antiserum, a CB6F1 anti-CMS 4 (Pool XIV) serum, was used to investigate the nature of the T cell regulatory structures recognized by these antibodies. Pool XIV antiserum was capable of blocking the induction of feedback suppression by Ly-1 TsiF, an SRBC-specific suppressor T cell factor secreted by Ly-1+, 2- I-J+ T cells. Ly-1 TsiF induces suppression by interacting with an Ly-1+,2+ I-J+ T cell target. Successful interaction of Ly-1 TsiF with its target cell requires genetic homology between inducer and target cells at the variable region of the immunoglobulin heavy chain gene complex (Igh-V). The addition of Pool XIV antiserum to primary in vitro anti-SRBC cultures resulted in blocking the ability of Ly-1 TsiF from Igha (BALB/c) and Ighj (CBA/J) mice to induce suppression on syngeneic cells, whereas suppression induced by Ly-1 TsiF in Ighb (B6), Ighc (DBA/2), Ighd (A/J), and Ighe (AKR) mice are unaffected by addition of the Pool XIV antiserum. The ability of Pool XIV antiserum to block Ly-1 TsiF activity is linked to the Igh region, because Pool XIV antiserum can block Ly-1 TsiF from BALB/c (H-2d, Igha) and the Igh congenic B.C9 (H-2b, Igha) while not affecting Ly-1 TsiF activity on B6 (H-2b, Ighb) or its Igh congenic C.B20 (H-2d, Ighb). In CB6F1 animals, Pool XIV antiserum could block the ability of CB6F1 Ly-1 TsiF to suppress BALB/c spleen cells but not B6 spleen cells. Conversely, Pool XIV antiserum could block the ability of BALB/c Ly-1 TsiF to suppress CB6F1 spleen cells, whereas B6 Ly-1 TsiF showed normal suppressive activity in the presence of Pool XIV antiserum. In contrast, Pool XIV was capable of blocking the ability of Ly-1 TsiF from BALB/c into CB6F1 bone marrow chimeras (BMC) to suppress both BALB/c and B6 mice, whereas the activity of Ly-1 TsiF from B6 into CB6F1 BMC on BALB/c or B6 spleen cells was unaffected by the addition of Pool XIV antiserum. We then investigated the molecular nature of the molecule recognized by Pool XIV antiserum on the Ly-1 TsiF.(ABSTRACT TRUNCATED AT 400 WORDS)

The European rabbit (Oryctolagus cuniculus) has been an important model for immunological studies but the study of its immunoglobulins (Ig) has been restricted to its unique IgA and IgG. Here, we studied the genetic diversity of IgM and IgE in several species of leporids and performed population genetics studies on European rabbit wild populations and domestic breeds. The leporids sequencing showed that these Ig are well conserved (98% sequence similarity among leporids), For IgM the Cµ1 and Cµ4 were the most diverse and most conserved domains, respectively, while for IgE the Cε1 was the most diverse domain and Cε2 and Cε3 the most conserved domains. The differences in the pattern of most conserved and most diverse domain between the Ig isotypes are most likely related to each isotype function. The genetic population data showed contrasting results for IgM and IgE. For both Ig, as expected, a greater diversity was observed in the original species range, the Iberian Peninsula. However, unexpectedly the genetic diversity found for IgE in the domestic animals is higher than that for the French wild populations. These results will increase knowledge of the genetic diversity of leporids and wild and domestic rabbit populations and are important tools for the management of wild populations and rabbitries.

Spleen cells from a Lewis rat immunized with affinity-purified B10 anti-(T,G)-A-L antibody were fused with the non-secreting murine hybridoma SP2/0. Cell lines secreting monoclonal antibodies specific for mu- and kappa-chains, as well as an idiotope on anti-(T,G)-A-L antibodies, were isolated and characterized. The anti-mu and -kappa antibodies, are true anti-isotypes, reacting with sera from all strains of mice tested. The anti-idiotope antibodies recognize a determinant on antibodies binding a GT-containing epitope. The proportion of anti-GAT antibody bearing the idiotope varies markedly in different murine strains. A 1000-fold higher level of antibody from Igha mice than from Ighb and Ighe mice is required to give an equivalent inhibition of the idiotope-anti-idiotope reaction. Analysis of monoclonal antibodies expressing the idiotope indicates that the affinity of binding between idiotope and anti-idiotope can vary by as much as two orders of magnitude. Immunoadsorbants prepared with anti-idiotope antibody bind suppressor factor secreted by a GAT-specific T-cell hybridoma.

The familial occurrence of allergic diseases was studied in 478 individuals and their family members. The results showed that there was pronounced familial clustering. Total serum IgE concentrations of atopic patients and their parents were well correlated. Moreover, the concentration of specific IgE of the patients and their parents was also well correlated, suggesting that IgE production was genetically determined. To determine if major structural abnormalities of IGHE, IGHEP1 and IGHEP2 genes might lead to aberrant control and subsequent increase in IgE concentration, genomic DNAs from 55 individuals, i.e., 31 atopic patients and their family members, were examined. We detected the IGHE, IGHEP1 and IGHEP2 genes in all 55 leukocyte DNAs. We could not find any large deletions or duplications in the IGHE, IGHEP1 and IGHEP2 genes of atopic patients with high serum IgE concentrations.

IgG subclass diversification is common in placental mammals. It has been well documented in humans and mice that different IgG subclasses, with diversified functions, synergistically regulate humoral immunity. However, our knowledge on the genomic and functional diversification of IgG subclasses in the pig, a mammalian species with high agricultural and biomedical importance, is incomplete. Using bacterial artificial chromosome sequencing and newly assembled genomes generated by the PacBio sequencing approach, we characterized and mapped the IgH C region gene locus in three indigenous Chinese breeds (Erhualian, Xiang, and Luchuan) and compared them to that of Duroc. Our data revealed that IGHG genes in Chinese pigs differ from the Duroc, whereas the IGHM, IGHD, IGHA, and IGHE genes were all single copy and highly conserved in the pig breeds examined. Most striking were differences in numbers of IGHG genes: there are seven genes in Erhualian pigs, six in the Duroc, but only five in Xiang pigs. Phylogenetic analysis suggested that all reported porcine IGHG genes could be classified into nine subclasses: IGHG1, IGHG2a, IGHG2b, IGHG2c, IGHG3, IGHG4, IGHG5a, IGHG5b, and IGHG5c. Using sequence information, we developed a mouse mAb specific for IgG3. This study offers a starting point to investigate the structure-function relationship of IgG subclasses in pigs.

The proteins secreted by parasitic nematodes are evolutionarily optimized molecules with unique capabilities of suppressing the immune response of the host organism. Neutrophil inhibitory factor (NIF), which is secreted by the dog hookworm Ancylostoma caninum, binds to the β2 integrin CD11b/CD18, which is expressed on human neutrophils, eosinophils, monocytes and macrophages and inhibits neutrophil-dependent lung injury and neutrophil invasion of ischaemic brain tissue. Neutrophils are key players in the pathogenesis of subepidermal autoimmune blistering diseases (sAIBDs), and their pathogenic activities are crucially dependent on β2 integrin functionality. Based on the template of single-stranded, dimerizing antibody derivatives, which are already used in cancer treatment, we designed a novel biologic, NIF-IGHE-CH4, comprising NIF and the dimerizing but otherwise inert constant heavy subdomain 4 (CH4) of human IgE (IGHE). This molecule was evaluated in a variety of in vitro assays, demonstrating its ability to inhibit pathogenically relevant neutrophil functions such as migration, adhesion and spreading, and release of reactive oxygen species. Finally, we confirmed that NIF-IGHE-CH4 inhibits blister formation in an ex vivo assay of sAIBD. These results suggest that NIF-IGHE-CH4 is a novel potential anti-inflammatory drug for the treatment of neutrophil-mediated diseases such as sAIBDs. This study promotes the drugs from bugs concept and encourages further research and development focused on turning parasite proteins into useful anti-inflammatory biologics.

Background: Epicutaneous sensitization is an important route for the production of IgE, and skin inflammation-induced IgE has recently been reported having features of natural antibody. Atopic dermatitis (AD) and psoriasis have differentially increased level of serum IgE; however, the production mechanism of IgE in these inflammatory skin diseases remains unknown.

Objective: To explore the origin of IgE in AD and psoriasis by analyzing the B cell receptor repertoire.

Methods: mRNA was prepared from peripheral blood mononuclear cells of AD and psoriasis patients that had elevated serum levels of IgE, and immunoglobulin heavy chain (IGH) repertoires were sequenced after reverse-transcription. Clonal lineages of B cells containing members expressing IgE were identified, and somatic hypermutations in IGH inherited from common ancestors within the clonal lineage were used to infer the relationships between B cells.

Results: The proportions of IGHE from AD and psoriasis were higher than that of normal control, which were positively correlated with the levels of serum total IgE. The somatic hypermutation value of IGHE variable region was lower than that of IGHG and IGHA, but higher than IGHM and IGHD, indicating a mixed natural and adaptive origins of IgE; and psoriasis demonstrated lower level of hypermutation than AD. The Shannon indexes of CDR3 in IGHE of AD and psoriasis were higher than that of normal control, also supporting the natural origin. The VH usage of IgE was weakly biased in AD and psoriasis patients with high level of house dust mite-specific IgE. Comparison of the number of shared mutations in multi-isotype lineages containing IgE showed that isotype-switching from IgG-expressing B cells might be the major source of IgE in AD and psoriasis.

Conclusion: IgE has heterogeneous origin in AD and psoriasis, and skin inflammation may contribute to the increased production of natural IgE.

Keywords: IgE; atopic dermatitis; class switch; hypermutation; immune repertoire; natural antibody; psoriasis.