HLA allelic variants encoding DR11 in diffuse and limited systemic sclerosis in Caucasian women

Human leukocyte antigen association in systemic sclerosis patients: our experience at a tertiary care center in North India

Introduction

Systemic sclerosis (SSc) is a chronic multisystem autoimmune rheumatic disease of unknown etiology. Several studies have established that SSc is triggered by a dynamic interplay between genetic factors and environmental stimuli. In the present study, we aimed to study the association of human leukocyte antigen (HLA) with familial and non-familial SSc patients [limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc)] from North India.

Methods

The HLA-A, B, DRB1, and DQB1 genotyping of 150 (70 lcSSc and 80 dcSSc) adult-onset SSc patients and 150 age-gender-matched healthy controls were performed with sequence-specific oligonucleotide (SSO) typing kits using the luminex platform. HLA typing for HLA class I (A, B, and C) and II (DRB1, DQB1, and DPB1) in five North Indian families consisting of parent-child/sibling pairs affected with SSc or overlap syndrome was performed by Next Generation Sequencing (NGS) with Illumina MiniSeq.

Rseults

Among the non-familial SSc patients, HLA- DRB1*11 (P = 0.001, OR: 2.38, P c = 0.01) was identified as a risk allele, and DRB1*12 (P = .0001, OR: 0.00, P c = 0.001) as a protective allele. There was no statistical association found with HLA-DQB1*. Also, no significant association was observed between HLA antigens and different clinical subsets (lcSSc and dcSSc) of SSc. Two cases of familial SSc patients had the DRB1*11 allele. The DRB1*12 allele was absent in all the familial SSc patients.

Discussion

HLA DRB1*11 (risk allele) and DRB1*12 (protective allele) were found to be strongly associated with non-familial SSc patients and partially explain the disease's familial clustering, supporting the susceptible genetic background theory for SSc development. The study also indicates the HLA allele as a common genetic risk factor in distinct autoimmune diseases contributing to overlap syndrome or polyautoimmunity.

Clinical, Serological, and Genetic Characteristics of a Hungarian Myositis-Scleroderma Overlap Cohort

Overlap myositis is a distinct subgroup of idiopathic inflammatory myositis (IIM) with various clinical phenotypes. The aim of this study was to determine the clinical, serological, and genetic features of systemic sclerosis (SSc)-IIM overlap patients. It was a retrospective study using clinical database of 39 patients, fulfilling both the criteria of SSc and IIM. 56.4% of the patients had limited cutaneous, 43.6% had diffuse cutaneous SSc, whereas 7.7% of the patients had dermatomyositis and 92.3% polymyositis. The two diseases occurred simultaneously in 58.97%, while 10.26% in myositis and 30.77% in scleroderma were initially diagnosed. The frequencies of organ involvement were interstitial lung disease 71.8%, dysphagia 66.7%, cardiac involvement 41%, pulmonary arterial hypertension (PAH) 30.8%, and renal involvement 12.8%, respectively. The presence of human leukocyte antigen (HLA) − DRB1∗03 and DQA1∗051∗01 alleles were significantly higher in the overlap patients than in healthy controls (82.35% vs. 27.54%; p < 0.0001 and 88.24% vs. 30.16; p < 0.0001). Certain clinical parameters, such as fever at diagnosis (41.67% vs. 7.41%, p = 0.0046), cardiac involvement (83.33% vs. 22.22%, p = 0.0008), subcutaneous calcinosis (41.66 vs. 11.11, p = 0.01146), and claw hand deformity (25% vs. 11.11%, p = 0.00016) were significantly associated with the presence of PAH. Upon comparison, the overlap patients and anti-Jo-1 positive antisynthetase patients showed similarities in terms of genetic results and major clinical features; however, SSc-IIM overlap patients could be distinguished with higher erythrocyte sedimentation rate (ESR) level, more frequent presence of Raynaud's phenomenon (p < 0.0001; OR: 20.00), dysphagia (p < 0.0001; OR: 15.63), and infrequent livedo reticularis (p < 0.01; OR: 0.11). SSc-IIM overlap myositis is a unique group within IIM-s possessing characteristic clinical features.

Systemic sclerosis in mother and daughter with susceptible HLA haplotype and anti-topoisomerase I autoantibodies

Systemic sclerosis is a rare systemic autoimmune rheumatic disease which is thought to be polygenic disorder contributed by both genetic and environmental factors. A positive family history of SSc is the strongest risk factor yet identified for SSc; however, the absolute risk for each family member remains quite low. A systematic literature search was performed in MEDLINE and Scopus database for studies published only in English that investigated the prevalence of SSc in first-degree relatives of SSc patients and whether SSc family members have greater frequency of I autoantibodies (ATA) than expected. Following keywords and terms: "systemic sclerosis", "scleroderma", "familial","ATA", "topoisomerase", and "anti-Scl70" were used to select the appropriate articles. From the 21 initially identified articles, 16 were eliminated because of the inclusion criteria, and five articles concerning familial occurrence of SSc in first-degree relatives positive for ATA were included for further analysis. Two case reports were described-a daughter and a mother diagnosed with systemic sclerosis with ATA tested for specific genotype. In both cases, patients had antinuclear autoantibodies (ANA) at a titer of > 1:1280, AC-29 cell pattern according to ICAP, and their sera were positive for ATA. In addition, anti-SSA/Ro60 autoantibodies were found in the case of the mother. Complementary to ATA positivity, the daughter was also positive for AMA-M2 autoantibodies. The results showed that our patients shared HLA-DRB1*1104-DQA1*0501-DQB1*0301 haplotype and had positive ATA, which corresponds to the strong association between ATA in white subjects and HLA-DRB1*1104, DQA1*0501, DQB1*0301 haplotype (OR = 6.93). Our patients not only shared a risky HLA haplotype for SSc but also manifested with a similar immunological activity, given that they were both positive for ATA. Although infrequent, ATA-positive SSc patients could develop scleroderma renal crisis, as in the case of the mother. Therefore, careful monitoring of the renal function is the best strategy for the case of the daughter. A positive family history is an important hint for patients suspected of autoimmune disease. The cases of familial SSc are quite rare, but they give us the opportunity to compare the genetic background, environmental risk factors, SSc phenotype, ANA type, and prevention of the complications in the course of the disease.

Human leukocyte antigen (HLA)-DRB1 allele polymorphisms and systemic sclerosis

Objectives: Human leukocyteantigen (HLA) is the most important gene for immune system regulation. Although studies have evaluated the association between HLA-DRB1 allele polymorphisms and systemic sclerosis (SSc), their results are still controversial. We performed a meta-analysis to assess the association of HLA-DRB1 alleles with risk of SSc.Methods: Electronic database were systematically searched for articles, a total of 11 case-control studies including 3268 cases and 5548 controls were analyzed. Odds ratio (ORs) and 95% confidence intervals were used to assess the association of HLA-DRB1 alleles with SSc. The relationship between SSc-related autoantibodies and DRB1 alleles was also analyzed.Results: In the overall analysis, four alleles (DRB1*04:03, DRB1*08, DRB1*11, and DRB1*11:04) increased the risk of SSc; however, five alleles (DRB1*07, DRB1*11:01, DRB1*13, DRB1*13:01, and DRB1*14) had the opposite effect. Analysis of subgroups by ethnicity indicate that DRB1*11:01 and DRB1*13:01 confer a protective effect in Caucasians, while DRB1*11:04 was associated with a higher risk of SSc. For Asian, DRB1*13:02 was found to be a protective factor. In addition, the frequency of DRB1*11:04 alleles was significantly increased in ATA⁺ SSc patients compared with ATA^- SSc patients.Conclusion: DRB1*04:03, DRB1*08, DRB1*11, and DRB1*11:04 were associated with the risk of SSc. Additionally, DRB1*11 and DRB1*11:04 were association with ATAs.

Characterization of the HLA-DRβ1 third hypervariable region amino acid sequence according to charge and parental inheritance in systemic sclerosis

Background

Specific HLA class II alleles are associated with systemic sclerosis (SSc) risk, clinical characteristics, and autoantibodies. HLA nomenclature initially developed with antibodies as typing reagents defining DRB1 allele groups. However, alleles from different DRB1 allele groups encode the same third hypervariable region (3rd HVR) sequence, the primary T-cell recognition site, and 3rd HVR charge differences can affect interactions with T cells. We considered 3rd HVR sequences (amino acids 67–74) irrespective of the allele group and analyzed parental inheritance considered according to the 3rd HVR charge, comparing SSc patients with controls.

Methods

In total, 306 families (121 SSc and 185 controls) were HLA genotyped and parental HLA-haplotype origin was determined. Analysis was conducted according to DRβ1 3rd HVR sequence, charge, and parental inheritance.

Results

The distribution of 3rd HVR sequences differed in SSc patients versus controls (p = 0.007), primarily due to an increase of specific DRB1*11 alleles, in accord with previous observations. The 3rd HVR sequences were next analyzed according to charge and parental inheritance. Paternal transmission of DRB1 alleles encoding a +2 charge 3rd HVR was significantly reduced in SSc patients compared with maternal transmission (p = 0.0003, corrected for analysis of four charge categories p = 0.001). To a lesser extent, paternal transmission was increased when charge was 0 (p = 0.021, corrected for multiple comparisons p = 0.084). In contrast, paternal versus maternal inheritance was similar in controls.

Conclusions

SSc patients differed from controls when DRB1 alleles were categorized according to 3rd HVR sequences. Skewed parental inheritance was observed in SSc patients but not in controls when the DRβ1 3rd HVR was considered according to charge. These observations suggest that epigenetic modulation of HLA merits investigation in SSc.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1253-9) contains supplementary material, which is available to authorized users.

Genomic and genetic studies of systemic sclerosis: A systematic review

Systemic sclerosis is an autoimmune rheumatic disease characterised by fibrosis, vasculopathy and inflammation. The exact aetiology of SSc remains unknown but evidences show that various genetic factors may be involved. This review aimed to assess HLA alleles/non-HLA polymorphisms, microsatellites and chromosomal abnormalities that have thus far been associated with SSc. PubMed, Embase and Scopus databases were searched up to July 29, 2015 using a combination of search-terms. Articles retrieved were evaluated based on set exclusion and inclusion criteria. A total of 150 publications passed the filters. HLA and non-HLA studies showed that particular alleles in the HLA-DRB1, HLA-DQB1, HLA-DQA1, HLA-DPB1 genes and variants in STAT4, IRF5 and CD247 are frequently associated with SSc. Non-HLA genes analysis was performed using the PANTHER and STRING₁₀ databases. PANTHER classification revealed that inflammation mediated by chemokine and cytokine, interleukin and integrin signalling pathways are among the common extracted pathways associated with SSc. STRING₁₀ analysis showed that NFKB1, CSF3R, STAT4, IFNG, PRL and ILs are the main "hubs" of interaction network of the non-HLA genes associated with SSc. This study gathers data of valid genetic factors associated with SSc and discusses the possible interactions of implicated molecules.

Brief Report: HLA-DRB1, DQA1, and DQB1 in Juvenile-Onset Systemic Sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is a rare disease that is particularly uncommon in children. Specific HLA alleles have been associated with SSc in adults. This study was undertaken to investigate HLA class II alleles in juvenile-onset SSc.

METHODS

DRB1, DQA1, and DQB1 alleles were determined by DNA-based HLA typing. Analyses were conducted comparing Caucasian patients with juvenile-onset SSc (n = 76) to healthy Caucasian controls (n = 581).

RESULTS

Initial analyses focused on HLA class II associations previously reported in adult Caucasian patients with SSc. The frequency of DRB1*11 was not significantly increased in juvenile-onset SSc (22.4% of patients with juvenile-onset SSc versus 17.6% of controls; odds ratio [OR] 1.35, P = 0.34), nor were the specific DRB1*11:01 or *11:04 alleles. DQA1*05, a risk factor previously identified in adult men with SSc, was increased in patients with juvenile-onset SSc versus controls (57.9% versus 44.1%; OR 1.76, P = 0.027), as was DRB1*03 (34.2% versus 22.5%; OR 1.79, P = 0.031). Secondary analyses of all DRB1 allele groups revealed an association with DRB1*10 (10.5% of patients with juvenile-onset SSc versus 1.5% of controls; OR 7.48, P = 0.0002). As this is a new observation, correction was made for multiple comparisons of 13 different DRB1 allele groups; results nevertheless remained significant (P = 0.003). Also, a lower frequency of DRB1*01 was observed in patients with juvenile-onset SSc who were younger at disease onset (OR 0.06, P = 0.01) and in those with antibodies to topoisomerase (OR 0.14, P = 0.024).

CONCLUSION

Associations of HLA alleles with juvenile-onset SSc differed from associations with SSc in women, but were similar to associations with SSc in men. Additionally, a novel association with DRB1*10 was observed in children. The greatest proportion of genetic risk of SSc is contributed by the HLA complex, and the current study reveals the importance of the association of HLA class II genes in juvenile-onset SSc.

Evaluation of X Chromosome Inactivation with Respect to HLA Genetic Susceptibility in Rheumatoid Arthritis and Systemic Sclerosis

Background

Autoimmune diseases, including rheumatoid arthritis (RA) and systemic sclerosis (SSc) are characterized by a strong genetic susceptibility from the Human Leucocyte Antigen (HLA) locus. Additionally, disorders of epigenetic processes, in particular non-random X chromosome inactivation (XCI), have been reported in many female-predominant autoimmune diseases. Here we test the hypothesis that women with RA or SSc who are strongly genetically predisposed are less susceptible to XCI bias.

Methods

Using methylation sensitive genotyping of the androgen receptor (AR) gene, XCI profiles were performed in peripheral blood mononuclear cells from 161 women with RA, 96 women with SSc and 100 healthy women. HLA-DRB1 and DQB1 were genotyped. Presence of specific autoantibodies was documented for patients. XCI skewing was defined as having a ratio ≥ 80:20 of cells inactivating the same X chromosome.

Results

110 women with RA, 68 women with SSc, and 69 controls were informative for the AR polymorphism. Among them 40.9% of RA patients and 36.8% of SSc patients had skewed XCI compared to 17.4% of healthy women (P = 0.002 and 0.018, respectively). Presence of RA-susceptibility alleles coding for the “shared epitope” correlated with higher skewing among RA patients (P = 0.002) and such correlation was not observed in other women, healthy or with SSc. Presence of SSc-susceptibility alleles did not correlate with XCI patterns among SSc patients.

Conclusion

Data demonstrate XCI skewing in both RA and SSc compared to healthy women. Unexpectedly, skewed XCI occurs more often in women with RA carrying the shared epitope, which usually reflects severe disease. This reinforces the view that loss of mosaicism in peripheral blood may be a consequence of chronic autoimmunity.

HLA Class I and II Blocks Are Associated to Susceptibility, Clinical Subtypes and Autoantibodies in Mexican Systemic Sclerosis (SSc) Patients

INTRODUCTION

Human leukocyte antigen (HLA) polymorphism studies in Systemic Sclerosis (SSc) have yielded variable results. These studies need to consider the genetic admixture of the studied population. Here we used our previously reported definition of genetic admixture of Mexicans using HLA class I and II DNA blocks to map genetic susceptibility to develop SSc and its complications.

METHODS

We included 159 patients from a cohort of Mexican Mestizo SSc patients. We performed clinical evaluation, obtained SSc-associated antibodies, and determined HLA class I and class II alleles using sequence-based, high-resolution techniques to evaluate the contribution of these genes to SSc susceptibility, their correlation with the clinical and autoantibody profile and the prevalence of Amerindian, Caucasian and African alleles, blocks and haplotypes in this population.

RESULTS

Our study revealed that class I block HLA-C*12:03-B*18:01 was important to map susceptibility to diffuse cutaneous (dc) SSc, HLA-C*07:01-B*08:01 block to map the susceptibility role of HLA-B*08:01 to develop SSc, and the C*07:02-B*39:05 and C*07:02-B*39:06 blocks to map the protective role of C*07:02 in SSc. We also confirmed previous associations of HLA-DRB1*11:04 and -DRB1*01 to susceptibility to develop SSc. Importantly, we mapped the protective role of DQB1*03:01 using three Amerindian blocks. We also found a significant association for the presence of anti-Topoisomerase I antibody with HLA-DQB1*04:02, present in an Amerindian block (DRB1*08:02-DQB1*04:02), and we found several alleles associated to internal organ damage. The admixture estimations revealed a lower proportion of the Amerindian genetic component among SSc patients.

CONCLUSION

This is the first report of the diversity of HLA class I and II alleles and haplotypes Mexican patients with SSc. Our findings suggest that HLA class I and class II genes contribute to the protection and susceptibility to develop SSc and its different clinical presentations as well as different autoantibody profiles in Mexicans.

An insight into rheumatology in Thailand

Despite the fact that rheumatic diseases constitute a common health care problem in Thailand, improvements in rheumatology education, research and health care are still required. Low numbers of rheumatologists, their uneven distribution, lack of time to perform both clinical and basic research, lack of patient compliance and restricted access to effective medication comprise some of the barriers that need to be overcome to establish rheumatology education, research and care with a Western-country benchmark. The annual academic activities provided by the Thai Rheumatism Association for rheumatologists, general practitioners, allied health professionals and patients can advance only some forms of education and health care. Better cooperation between the Thai Rheumatism Association, the Royal College of Physicians of Thailand, the Ministry of Public Health and the Thai government is needed to improve rheumatology training, care and research in the country.

HLA markers for poor prognosis in systemic sclerosis Brazilian patients

Objectives. The aim of this study was to evaluate human leukocyte antigen (HLA) involvement in the disease expression and poor prognostic clinical features (pulmonary fibrosis and pulmonary arterial hypertension) in patients diagnosed with systemic sclerosis (SSc) in a multiethnic population. Methods. SSc patients followed up between 2008 and 2011 were included, and clinical data were obtained through records review. Molecular HLA typing was performed (polymerase chain reaction amplification technique using specific primer sequences). The statistical analysis involved Fisher's exact test and Pearson's corrected chi-square test. P  values ≤ 0.05 were considered significant. The delta method was used to estimate the variance of the prevalence ratio (PR). Results. A total of 141 patients (120 women and 21 men) with SSc were studied, including 33.3% with diffuse cutaneous SSc (dcSSc), 62.4% with limited cutaneous SSc (lcSSc), and 4.3% with sine scleroderma. Pulmonary fibrosis was present in 61 patients (43.3%), and the HLA-A∗30 and DQB1∗04 alleles were related to susceptibility. In contrast, the HLA-DRB1∗01 and DQB1∗05 alleles were protective. Pulmonary arterial hypertension was diagnosed in 19 patients (13.5%) and was associated with HLA-B∗35 and C∗04; in contrast, C∗03 seemed to be protective. Conclusions. Our current study documents the association of some classes I and II HLA alleles with the most severe clinical manifestations in a multiethnic case series. Our findings differed slightly from the previous data in other populations.

Systemic sclerosis: genetics and epigenetics

Systemic sclerosis (SSc) is an autoimmune disease characterized by immune abnormalities, vascular obliteration, excessive extracellular matrix deposition, and fibrosis of the skin and/or internal organs. To date, the exact etiology of this complicated disease remains unknown. Over the past few years, however, the role of genetic susceptibility and epigenetic modifications caused by environmental factors have been intensively studied in relation to the pathogenesis of this disease, and important advances have been made. This review focuses on the recent progress in the field of SSc research, including HLA and non-HLA susceptibility genes identified in genome-wide association studies (GWAS), and aberrant epigenetic modifications of gene loci associated with SSc. HLA genes most closely linked with SSc susceptibility include HLA-A, -B, -C, -DR, -DP and -DQ. A large number of non-HLA genes were also reported. It has also been noted that different genetic variants can be linked to specific clinical patterns. Finally, DNA demethylation of regulatory genes (eNOS, CD40L and CD70), therapeutic effects associated with Trichostatin A (TSA) treatment, and abnormal expression of a large spectrum of microRNAs (miR-21, -31, -146, -503, -145, -29b, etc.) are all observed in SSc. Overall, the findings presented in this review illustrate how both genetic and epigenetic aberrations play important roles in the development of SSc; however, several unanswered questions continue to impede our understanding of this complex disease. Future research should focus on the identification of new biomarkers for early diagnosis and prognosis, which will help improve the clinical outcome of patients with SSc.

Human leukocyte antigens and Gaucher disease

BACKGROUND

Gaucher disease (GD) is caused by the reduced activity of lysosomal enzyme glucocerebrosidase, which leads to the accumulation of glucocerebroside in macrophages and a chronic stimulation of the immune system. GD is divided into 3 main types according to the presence or absence of neurological involvement and to its presentation (acute or chronic). Gaucher cells show an increase in their expression of HLA-DR antigens on their surface, and there is an increase in levels of antigen-presenting molecules. Over 100 diseases have already been associated to HLA antigens; however, this association has never been studied in GD.

OBJECTIVES

To analyze the variability of HLA genes in a Southern Brazilian sample of GD patients, to compare it with controls, and to look for associations with clinical manifestations.

METHODOLOGY

Thirty-one GD patients (24 mild, 4 moderate, and 3 severe) were included in the study. They were typed for HLA A, B, and DR and compared to 250 healthy controls. The clinical data were obtained from the review of medical records.

RESULTS/DISCUSSION

There was a significant difference in the frequency of B37 allele among patients when compared to controls (p=0.011, OR 13.28). An association was found between DR11 (p=0.008) and DR13 (p=0.011) alleles and the severity of the disease. DR11 allele seems to be associated to neurologic compromise, while DR13 seems to be associated to osteonecrosis.

CONCLUSION

Our data suggest a possible association of HLA variants and GD. The HLA variants must be further studied, for they seem to be a phenotype-modifier factor for GD.

Pattern of skin thickness progression and clinical correlation in Thai scleroderma patients

BACKGROUND

Skin thickness progression in scleroderma (SSc) varies in daily clinical practice observation.

OBJECTIVES

To define the pattern of skin thickness among Thai sufferers of SSc and to ascertain the clinical correlation with each skin pattern.

METHODS

A 3-year follow-up cohort was performed on patients over 15 years of age in Khon Kaen, Thailand, between January 1, 2005 and December 31, 2006. The progression of skin thickness equals the modified Rodnan skin score at the end minus the score at onset divided by the duration of the disease.

RESULTS

SSc cases (117) were included and the female-to-male ratio was 70:47. The mean age at onset was 49.8 years (range 24.4-75.5). The most common skin patterns were: (i) 'slow progression to peak then slow regression' (77 cases; 65.8%); followed by (ii) 'continuous slow progression' (37; 31.6%); (iii) 'continuous intermediate progression' (2; 1.7%); and (iv) 'slow progression to peak then intermediate regression' (1; 0.9%). The respective mean peak skin score and duration of disease at peak skin score was 19.8 points (range 4-45) and 20.3 months (range 1.0-42.2). Only telangiectasia at onset and contracture of joint(s) were related to 'continuous slow progression' of skin thickness with P=0.001 and P=0.042, respectively. Neither SSc subsets nor internal organ involvement were correlated with skin thickness pattern.

CONCLUSION

The most common skin pattern in Thai SSc was 'slow progression to peak then slow regression'. Telangiectasia at onset and contracture of joint(s) were predictive of continuous progressive skin thickness in the first 3 years.

Comparing HLA shared epitopes in French Caucasian patients with scleroderma

Although many studies have analyzed HLA allele frequencies in several ethnic groups in patients with scleroderma (SSc), none has been done in French Caucasian patients and none has evaluated which one of the common amino acid sequences, ⁶⁷FLEDR⁷¹, shared by HLA-DRB susceptibility alleles, or ⁷¹TRAELDT⁷⁷, shared by HLA-DQB1 susceptibility alleles in SSc, was the most important to develop the disease. HLA-DRB and DQB typing was performed for a total of 468 healthy controls and 282 patients with SSc allowing FLEDR and TRAELDT analyses. Results were stratified according to patient’s clinical subtypes and autoantibody status. Moreover, standardized HLA-DRß1 and DRß5 reverse transcriptase Taqman PCR assays were developed to quantify ß1 and ß5 mRNA in 20 subjects with HLA-DRB1*15 and/or DRB1*11 haplotypes. FLEDR motif is highly associated with diffuse SSc (χ² = 28.4, p<10−6) and with anti-topoisomerase antibody (ATA) production (χ² = 43.9, p<10−9) whereas TRAELDT association is weaker in both subgroups (χ² = 7.2, p = 0.027 and χ² = 14.6, p = 0.0007 respectively). Moreover, FLEDR motif- association among patients with diffuse SSc remains significant only in ATA subgroup. The risk to develop ATA positive SSc is higher with double dose FLEDR than single dose with respectively, adjusted standardised residuals of 5.1 and 2.6. The increase in FLEDR motif is mostly due to the higher frequency of HLA-DRB1*11 and DRB1*15 haplotypes. Furthermore, FLEDR is always carried by the most abundantly expressed ß chain: ß1 in HLA DRB1*11 haplotypes and ß5 in HLA-DRB1*15 haplotypes.

In French Caucasian patients with SSc, FLEDR is the main presenting motif influencing ATA production in dcSSc. These results open a new field of potential therapeutic applications to interact with the FLEDR peptide binding groove and prevent ATA production, a hallmark of severity in SSc.

Passively acquired anti-SSA/Ro antibodies are required for congenital heart block following ovodonation but maternal genes are not

Anti-SSA/Ro antibodies are necessary but not sufficient to provoke autoimmune-associated congenital heart block (CHB). Genetic factors are likely contributory. Accordingly, HLA-related candidates and single-nucleotide polymorphisms in the promoter region of tumor necrosis factor α and codon 10 in transforming growth factor β1 (TGFβ1) were evaluated in a unique family: the surrogate mother (anti-SSA/Ro positive), the biologic father, and the CHB-affected child (product of ovodonation). There was an HLA mismatch between the affected child and the surrogate mother. However, both the biologic and the surrogate mothers shared DQ2 and the profibrosing leucine polymorphism at codon 10 of TGFβ. In conclusion, we observed that CHB can develop in a genetically unrelated child exposed in utero to anti-SSA/Ro antibodies. Testing for anti-SSA/Ro antibodies might be considered in women undergoing artificial fertilization. It is possible that there is no direct association of maternal genes beyond a contributory role in generating the autoantibody.

Association of HLA class II genes with systemic sclerosis in Spanish patients

OBJECTIVE

To examine the role of HLA-DRB1 and HLA-DQB1 alleles in the susceptibility to systemic sclerosis (SSc) and its clinical expression in a Spanish population.

METHODS

One hundred Spanish Caucasian patients with SSc and 130 controls were studied. Molecular HLA-DRB1 and HLA-DQB1 typing was performed by polymerase chain reaction (PCR) sequence-based typing and PCR sequence-specific oligonucleotide.

RESULTS

HLA-DRB1*11 was associated with genetic susceptibility to SSc, whereas HLA-DRB1*07 (HLA-DRB1*0701) showed a protective effect. A significant increase in the frequency of the DRB1*1104 allele was observed in patients with anti-topoisomerase I autoantibodies (anti-Topo I) while HLA-DRB1*01 and HLA-DQB1*05 alleles were significantly increased in patients with anti-centromere antibodies (ACA). The HLA-DRB1*11 allele was more frequent in patients with pulmonary fibrosis; however, no significant association with any HLA-DRB1 or DQB1 alleles was identified in patients with pulmonary arterial hypertension.

CONCLUSION

HLA alleles play a role in genetic susceptibility to SSc in Spanish patients. Some alleles are more prevalent in patients with pulmonary fibrosis and in patients with certain SSc-specific autoantibodies (anti-Topo I and ACA).

Skewed X-chromosome inactivation in scleroderma

Scleroderma is a female-prevalent autoimmune disease of unclear etiology. Two fundamental gender differences, skewed X-chromosome inactivation (XCI) and pregnancy-related microchimerism, have been implicated in scleroderma. We investigated the XCI patterns of female scleroderma patients and the parental origin of the inactive X chromosome in those patients having skewed XCI patterns (>80%). In addition, we investigated whether a correlation exists between XCI patterns and microchimerism in a well-characterized cohort. About 195 female scleroderma patients and 160 female controls were analyzed for the androgen receptor locus to assess XCI patterns in the DNA extracted from peripheral blood cells. Skewed XCI was observed in 67 (44.9%) of 149 informative patients and in 10 of 124 healthy controls (8.0%) [odds ratio (OR) = 9.3 (95% confidence interval (CI) 4.3-20.6, P < 0.0001)]. Extremely skewed XCI (>90%) was present in 44 of 149 patients (29.5%) but only in 3 of 124 controls (2.4%; OR = 16.9; 95% CI 4.8-70.4, P < 0.0001). Parental origin of the inactive X chromosome was investigated for ten patients for whom maternal DNA was informative, and the inactive X chromosome was of maternal origin in eight patients and of paternal origin in two patients. Skewed XCI mosaicism could be considered as an important risk factor in scleroderma.