The HLA-DRB1*0405 haplotype is most strongly associated with IDDM in Algerians.

Insulin-dependent diabetes mellitus (IDDM) in Caucasians is strongly associated with HLA-DR3-DQ2 and DR4-DQ8. In order to investigate the HLA class II associations with IDDM in Algerians, we have used polymerase chain reaction (PCR) and sequence specific oligonucleotide analysis (SSO) to identify DQA1, DQB1, and DRB1 alleles, haplotypes and genotypes in 50 unrelated IDDM patients and 46 controls from a homogeneous population in Western Algeria. Both DRB1*0301-DQA1*0501-DQB1*0201 (DR3-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) haplotypes were found at increased frequencies among the patients compared to controls (45% vs. 13%, RR = 5.5, Pc < 10(-5) and 37% vs. 4%, RR = 12.9, Pc < 10(-4), respectively). Among the latter, in contrast to other Caucasian populations, only DRB1*0405-DQA1*0301-DQB1*0302 was significantly increased in the Algerian patients (25% vs. 1% in controls, RR = 30.3, Pc < 10(-3). Accordingly, the highest risk of disease was observed in DRB1*0301-DQA1*0501-DQB1*0201/DRB1*0405-DQA1+ ++*0301-DQB1*0302 heterozygotes (34% in patients vs. 0% in controls; RR = 49; Pc < 10(-3). This observation and its comparison with DR-DQ haplotypes in other ethnic groups suggest that the DRB1*0405 allele which encodes an Asp57-negative beta chain may contribute to IDDM susceptibility in a similar way as Asp57-negative DQ beta chains.     

HLA-DRB1*01 and DRB1*04 alleles in Sardinian rheumatoid arthritis patients

In Sardinia, like in other Caucasoid populations, rheumatoid arthritis (RA) is significantly associated with HLA-DR4 and DR1 antigens. To discover which DR4 and DR1 alleles were associated with the disease we selected 22 Sardinian patients affected by RA. Fifty DR4+ and 28 DR1+ healthy individuals coming from the same geographical area were used as controls. In the Sardinian patients only two DRB1*04 alleles were observed: DRB1*0405 in 11 and DRB1*0403 in three patients. The DRB1*0102 allele was observed in two patients and DRB1*0101 in six patients. Hereditary predisposition to RA in Sardinia therefore seems to be almost exclusively associated with the DRB1*0405 and DRB1*0101 alleles which share the 67LLEQRRAA74-85VG86 epitope in the peptide binding groove.     

Imbalance of CD4+ lymphocyte subsets in patients with mixed connective tissue disease.

CD4+ (helper/inducer) T lymphocyte subsets were studied in the peripheral blood from patients with mixed connective tissue disease (MCTD) by double-labelling immunofluorescence. The proportion of CD4+CD45RA+ cells was higher (P less than 0.01) when compared with controls, whereas CD4+CD29+ cells were markedly diminished (P less than 0.001). CD4+CD29+ cells were lower than in patients with progressive systemic sclerosis who were studied in parallel. Upon stimulation with phytohaemagglutinin, CD4+ cells from MCTD patients showed a strong reactivity to acquire the CD29+ phenotype. Expression of high levels of CD29 and other adhesion molecules might lead to facilitated localization of CD4+ cells to inflamed tissue. It is suggested that an increased responsiveness of CD4+ cells to activation signals in vivo and accumulation of CD4+CD29+ cells at tissue sites could result in depletion of this cell subset in the peripheral blood of patients with MCTD.     

Derailed B cell homeostasis in patients with mixed connective tissue disease

Mixed connective tissue disease (MCTD) is a systemic autoimmune disorder, characterized by the presence of antibodies to U1-RNP protein. We aimed to determine phenotypic abnormalities of peripheral B cell subsets in MCTD. Blood samples were obtained from 46 MCTD patients, and 20 controls. Using anti-CD19, anti-CD27, anti-IgD and anti-CD38 monoclonal antibodies, the following B cell subsets were identified by flow cytometry: (1) transitional B cells (CD19 + CD27-IgD + CD38^high); (2) naive B cells (CD19 + CD27-IgD + CD38^low); (3) non-switched memory B cells (CD19 + CD27 + IgD+); (4) switched memory B cells (CD19 + CD27 + IgD-); (5) double negative (DN) memory B cells (CD19 + CD27-IgD-) and (6) plasma cells (CD19 + CD27^highIgD-). The proportion of transitional B cells, naive B cells and DN B lymphocytes was higher in MCTD than in controls. The DN B cells were positive for CD95 surface marker. This memory B cells population showed a close correlation with disease activity. The number of plasma cells was also increased, and there was an association between the number of plasma cells and the anti-U1RNP levels. Cyclophosphamide, methotrexate, and corticosteroid treatment decreased the number of DN and CD27^high B cells. In conclusion, several abnormalities were found in the peripheral B-cell subsets in MCTD, which reinforces the role of derailed humoral autoimmune processes in the pathogenesis.     

HLA-DRB1*04 and DRB1*10 are associated with resistance and susceptibility, respectively, in Brazilian and Vietnamese leprosy patients

The host genetic background has been considered one of the factors that influence leprosy outcome, a chronic infectious disease caused by Mycobacterium leprae. Genome scans demonstrated that the 6p21 region is associated with leprosy and a substantial number of population-based studies analyzing human leukocyte antigen (HLA) class II loci suggested association of HLA-DR with leprosy. However, some studies lacked robustness as they had limited power. Indeed, experimental designs require increased sample size to achieve adequate power, as well as replication studies with independent samples for confirmation of previous findings. In this work, we analyzed the influence of the HLA-DRB1 locus on leprosy susceptibility per se and disease type using a case-control design carried out in Brazilians (578 cases and 691 controls) and a replication study based on a family design in a Vietnamese population (n=194 families). The results showed that HLA-DRB1*10 is associated with susceptibility to leprosy and HLA-DRB1*04 is associated with resistance, both in the Brazilian and Vietnamese populations suggesting that these alleles play an important role in the activation of cellular immune responses against M. leprae.     

Association of HLA-DRB1*0901-DQB1*0303 haplotype with microscopic polyangiitis in Japanese

Microscopic polyangiitis (MPA) is a rare and severe form of systemic necrotizing vasculitis associated with myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibody (ANCA). We previously reported significant association of HLA-DRB1*0901 with MPA. To define the susceptibility loci within the HLA region, we determined the genotypes of HLA-DQB1, DPB1, B and C in 50 patients with MPA and 77 unrelated Japanese controls. In addition to HLA-DRB1*0901, significant association of DQB1*0303 (allele carrier frequencies 50% in MPA, 29.9% in controls, odds ratio 2.35, P = 0.017) was detected. These alleles were in strong linkage disequilibrium (D' = 0.95, r2 = 0.82). Increased frequency was also observed for DPB1*0201, B*15111 and Cw*0303, which was at least partly accounted for by linkage disequilibrium with DRB1*0901 and DQB1*0303. These results indicate that DRB1*0901-DQB1*0303 haplotype represents the primary genetic risk for MPA within the HLA region in Japanese, and provides the basis that future functional studies on the role of HLA in MPA should target DR9, DQ9 and DR53 proteins encoded by this haplotype.     

HLA-DRB1*03 is a susceptibility gene in patients with Graves' disease with and without ophthalmopathy

We sought an association between certain human leucocyte antigen (HLA) markers and Graves' disease (GD) with and without ophthalmopathy (OP). One hundred and thirty-one Turkish patients with GD (50 without OP, 81 with OP) and 250 local healthy controls were studied. HLA-DRB1 typing was performed by using polymerase chain reaction-sequence-specific primers (PCR-SSP) method. The frequencies of DRB1*03 was significantly increased in GD compared to controls (OR = 2.07; 95% CI = 1.24-3.44), whereas DRB1*13 (OR = 0.33; 95% CI = 0.18-0.61) and DRB1*07 (OR = 0.31; 95% CI = 0.13-0.70) were significantly increased in controls compared to patients. None of the three associations showed any specificity to the OP group.     

Heterogeneity of HLA-DRB1*04 and its associated haplotypes in the North Indian population

HLA-DR4 has been implicated in several diseases including rheumatoid arthritis (RA) and type I diabetes, the strength of associations being ethnically variable. Unusually high level of heterogeneity in DR4-DQB1 haplotypes has been reported in the Indian population. The present study is an attempt to determine the genetic diversity of the HLA-DR4 allelic family and its associated DQA1-DQBI haplotypic combinations in the healthy North Indian population. Using PCR-SSP and PCR-SSOP techniques, nine subtypes of DR4 were encountered of which DRB1*0403 was the most predominant allele (34.8%) followed by *0404 (27%), *0401 (14.6%), and *0405 (11%). No examples of *0402, *0409, *0411, *0413-*0417, and *0419-23 were encountered, although a few other subtypes, *0410 (three examples), *0406 and *0418 (two examples each), and *0407, *0408, and *0412 (single example each) occurred infrequently in a cohort of 85 HLA-DR4 positive samples studied. Most of these subtypes occurred in combination with DQA1*03-DQB1*0302 (69.5%). DRB1*0403 and *0404 exhibited maximum heterogeneity of DQB1 combinations. Haplotype data revealed the presence of 15 different DR4-DQ haplotypes, four of which were found to be "unique" to Asian Indians, not reported in any other population. These results help to explain the observed variability in DR4 associations in autoimmune diseases in Asian Indians and provide support for scientific and historical documentation of extensive admixture in the Indian subcontinent.     

HLA-DRB1*04 may predict the severity of disease in a group of Iranian COVID-19 patients

Human leukocyte antigen (HLA) genes with extreme diversity can make a contribution for individual variations to the immune response against SARS-COV-2 infection. This study aimed to explore the distributions of HLA class II alleles frequencies and their relations with disease severity in a group of Iranian COVID-19 patients. This prospective and case-control study was conducted on 144 COVID-19 patients including 46 cases with moderate form, 54 cases with severe and 44 cases with critical disease. HLA-DRB1 and -DQB1 allele families were determined by PCR-SSP method and compared between three groups of the patients and in comparison to 153 ethnic-matched healthy controls. The patients group showed lower frequencies of HLA-DRB1*15 (OR = 0.57, P = 0.06), DRB1*15 ~ DQB1*05 haplotype (P = 0.04) and DRB1*15/DRB1*04 genotype (P = 0.04) in compare with healthy controls. Moderate COVID-19 patients had higher frequencies of HLA-DRB1*04 (P = 0.03), HLA-DRB1*10 (P = 0.05) and DRB1*04/DRB1*11 genotype (P = 0.01). Also, a higher significantly frequency of HLA-DRB1*03 allele group was observed in the critical patients versus controls (P = 0.01). Multiple logistic regression analysis revealed that the presence of DRB1*04 allele group was negatively associated with development of severe and critical disease (OR: 0.289, P = 0.005). Our results indicate a possible contribution of some HLA class II alleles in disease severity and clinical features of COVID-19 disease.     

Rheumatoid arthritis association in Colombian population is restricted to HLA-DRB1*04 QRRAA alleles

In most ethnic groups genetic susceptibility to rheumatoid arthritis (RA) is associated with certain HLA-DRB1 alleles encoding a similar sequence motif called the 'shared epitope' (SE) spanning amino acid positions 70 to 74 in the third diversity region of the outermost domain of the HLA-DRB1 molecule. We examined the association of the SE and RA in 83 Colombian women with established RA and 90 healthy controls. The group HLA-DRB1*04 was associated with RA with respect to controls (47% vs 18%, respectively. OR: 4.1, 95%CI: 2.1-8.2, P < 0.001). HLA-DRB1 alleles carrying the SE QRRAA, but not those carrying QKRAA or RRRAA, were associated with disease (OR: 3.7, 95%CI: 1.73-7.83, P = 0.0009). This association was stronger among HLA-DRB1*04 carriers (OR: 23, 95%CI: 1.3-414, P = 0.002). In our population, the SE QRRAA expressed in DRB1*04 alleles appears critical in identifying women with increased susceptibility to RA.     

HLA DRB1*130101-DQB1*060101 haplotype is associated with acute chest syndrome in sickle cell anemia patients

We investigated the association of human leukocyte antigens (HLA) class II alleles and haplotypes with the pathogenesis of acute chest syndrome (ACS) in 186 sickle cell anemia (SCA) patients, of whom 58 had documented ACS (new pulmonary infiltrate, fever, and other associated clinical events) and 128 with a negative history of ACS, serving as controls. HLA DRB1* and -DQB1* genotyping was performed by polymerase chain reaction–sequence-specific priming. Of the DRB1* and DQB1* alleles analyzed, only DRB1*130101 ( Pc  < 0.001) was positively associated with ACS. DRB1*130101-DQB1*060101 haplotype was more prevalent among ACS patients ( P  = 0.018), thus conferring disease susceptibility. Specific HLA alleles and haplotypes may influence ACS risk in SCA patients, and specific HLA genotypes may be useful markers for identifying high-risk SCA ACS patients.     

Protective association of HLA-DRB1*13:02, HLA-DRB1*04:06, and HLA-DQB1*06:04 alleles with cervical cancer in a Korean population

Human leukocyte antigen (HLA) class II alleles have been previously associated with cervical cancer. However, these associations vary widely across racial and ethnic groups. Therefore, we evaluated the effect of HLA class II alleles on cervical cancer in a Korean population. HLA-DRB1, HLA-DQB1, and HLA-DQA1 alleles were analyzed in 457 cervical cancer patients and compared to those of 926 control subjects. The odds ratio (OR) of each allele between the patients and controls was calculated using the logistic regression model. Patients, had significantly lower frequencies of HLA-DRB1 and HLA-DQB1 alleles than control subjects: HLA-DRB1*13:02:01 (4.4% vs 8.8%; OR 0.48, 95% confidence interval (CI) 0.27–0.84; p = 0.001), HLA-DRB1*04:06 (2.1% vs 4.7%; OR 0.44, 95% CI 0.20–0.97; p = 0.033), and HLA-DQB1*06:04:01 (2.3% vs 5.0%; OR 0.46, 95% CI 0.22–0.94; p = 0.021). No significant association was observed for HLA-DQA1. Protective associations between HLA-DRB1*13:02, HLA-DRB1*04:06, and HLA-DQB1*06:04 alleles and cervical cancer were found in the Korean population     

MICA*A4 protects against ulcerative colitis,whereas MICA*A5.1 is associated with abscess formation and age of onset

Ulcerative colitis (UC) is one of the two major forms of inflammatory bowel disease, the aetiology of which remains unknown. Several studies have demonstrated the genetic basis of disease, identifying more than 130 susceptibility loci. The major histocompatibility complex class I chain‐related gene A (MICA) is a useful candidate to be involved in UC pathogenesis, because it could be important in recognizing the integrity of the epithelial cell and its response to stress. The aim of this study was to analyse the relationship between polymorphisms in the transmembrane domain of MICA and susceptibility to develop UC. A total of 340 patients with UC and 636 healthy controls were genotyped for MICA transmembrane polymorphism using a polymerase chain reaction (PCR) combined with fluorescent technology. Different MICA alleles were determined depending on the PCR product size. The allele MICA*A4 was less frequent in patients than in controls (P = 0·003; OR = 0·643), and this protective role is higher when it forms haplotype with B*27 (P = 0·002; OR = 0·294). The haplotype HLA‐B*52/MICA*A6 was also associated with UC [P = 0·001; odds ratio (OR) = 2·914]. No other alleles, genotypes or haplotypes were related with UC risk. Moreover, MICA*A5.1 is associated independently with abscesses (P = 0·002; OR = 3·096) and its frequency is lower in patients diagnosed between ages 17 and 40 years (P = 0·007; OR = 0·633), meaning an extreme age on onset. No association with location, extra‐intestinal manifestations or need for surgery was found.     

Severe pulmonary sarcoidosis is strongly associated with the haplotype HLA-DQB1*0602-DRB1*150101

Sarcoidosis is a multiorgan granulomatous disease of unknown etiology. Several lines of evidence suggest a genetic predisposition and associations have been demonstrated with HLA antigens. HLA-DQB1 has been proposed as one of the candidate genes. To investigate the relationship between DQB1 and sarcoidosis at the allele level, we typed 149 Dutch Caucasian sarcoidosis patients for DQB1 by sequence-based typing as the ultimate technique to identify all DQB1 alleles. Phenotype frequencies were compared with controls. Both groups were also typed for HLA-A, -B, and -DRB1 at the low-resolution level. To decide on the possible linkage with DR, all DRB1*15-positive patients were subsequently sequence-based typed. Results showed a statistically significant increase of DQB1*0602 in sarcoidosis patients. The increase was also proven for DRB1*150101. Because of the high linkage disequilibrium between DRB1*1501 and DQB1*0602 in Caucasians, it could not be decided which one was the primary association. The increase was most pronounced in patients with severe pulmonary sarcoidosis indicated by radiographic stages II-IV. Although not statistically significant, DRB1*03 and DQB1*0201 were increased in radiographic stage I compared with II-IV. This study provides evidence that the combination DQB1*0602/DRB1*150101 is a strong positive marker for severe pulmonary sarcoidosis.     

High frequency of the IL-2 −330 T/HLA-DRB1*1501 haplotype in patients with multiple sclerosis

We have evaluated the role of the HLA-DRB1*1501 allele and the IL-2 −330 T/G polymorphism and their interaction in susceptibility to multiple sclerosis on 360 patients and 426 matched healthy individuals. We used the SSP-PCR method to determine the alleles. Fisher's exact test was used to analyses. We observed a significant increase in the T allele at IL-2 −330 position in patients (OR = 1.34, P < 0.05), and the T/T and T/G genotypes were more frequent among patients than controls. The HLA-DRB1*1501 allele was overrepresented in patients as compared to the control group (OR = 1.7, P = 0.0006). The two-locus analysis of the interaction between the IL-2 promoter polymorphism and the HLA-DRB1 allele showed that the HLA-DRB1*1501/T haplotype was more frequent in patients than controls (OR = 16, P < 0.0001). Our findings support previous findings about the role of the HLA-DRB1*1501 allele in susceptibility to MS. This work also provides new findings about the importance of gene–gene interactions in the development of MS.     

Clinical and immunoserological characteristics of mixed connective tissue disease associated with pulmonary arterial hypertension

We investigated the clinical characteristics and immunoserological alterations in patients with mixed connective tissue disease (MCTD) associated with pulmonary arterial hypertension (PAH). Anti-U1RNP autoantibodies, anti-endothelial cell antibodies (AECA) and serum thrombomodulin (TM) as well as von Willebrand factor antigen (vWFAg) concentrations were measured in 25 patients with MCTD associated with PAH and in 154 MCTD patients without PAH. The results showed that the probability of survival was lower in MCTD patients with PAH than in the 154 MCTD-non-PAH patients (5-year survival rate in MCTD with PAH: 73%, versus 96% in MCTD-non-PAH; P < 0.01). AECA were more frequently present in the sera of MCTD patients with PAH than in MCTD-non-PAH (P < 0.001). Serum TM and vWFAg levels were higher in MCTD-PAH patients than in MCTD-non-PAH patients (TM: P < 0.001; vWFAg: P < 0.001). Significant correlation was noticed between the quantity of AECA and TM level (r = 0.466) as well as the quantity of AECA and vWFAg level (r = 0.550). In conclusion, our results suggest that in MCTD the presence of AECA and endothelial cell activation may play a role in the development of PAH and in the maintenance of obliterative vascular processes.     

Anti-nuclear matrix antibodies in mixed connective tissue disease

Purified serum antibodies of patients suffering from mixed connective tissue disease were tested for their immunological specificity against nuclear constituents of HeLa S3 cells. In the indirect immunofluorescent staining technique, using cells and nuclei as targets, a typical speckled intranuclear staining pattern was obtained, that persisted after degradation and extraction of all nucleic acids and their associated proteins. This treatment of nuclei with detergents, DNase, RNase and high salt concentrations leave intact only the so-called nuclear matrix which is an intranuclear proteinaceous network. Further proof that nuclear matrix proteins were targets of the autoimmune reaction was obtained after separation of these proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis and electrophoretic transfer to nitrocellulose (blotting). A specific number of blot-transferred matrix proteins reacted with purified serum antibodies of 10 patients with mixed connective tissue disease, whereas this reaction was negative with normal healthy individuals. IgG preparations of 7 patients with systemic lupus erythematosus showed a weak, if any, reaction with matrix constituents. Obviously, in some connective tissue diseases serum antibodies are expressed which are directed to specific nuclear matrix antigens.     

Association of HLA-DRB1*1502-DQB1*0501 haplotype with susceptibility to systemic lupus erythematosus in Thais

In this study, we investigated the association of HLA-DRB1 and DQB1 with Thai patients with SLE. A highly significant increase in the frequency of DRB1*1502 and DQB1*0501 was found in SLE patients compared with normal controls. DRB1*1501 and DRB1*1602 were also slightly increased. In contrast, DRB1*1202 and DQB1*0301 were decreased, and DRB1*0406 and DRB1*1401 were not found in the patients' group. The haplotype analysis revealed that DRB1*1502 - DQB1*0501 was most strongly associated with SLE, and also suggested a primary role for DRB1 rather than DQB1. Taken together with the previous report which demonstrated the association of the same haplotype in Taiwan, our present observations strongly suggested that DRB1*1502 - DQB1*0501 is the major HLA haplotype that confers susceptibility to SLE in the South-east Asian populations.