Human leukocyte antigens class I and class II alleles associated with vertical human immunodeficiency virus transmission - an exploratory study from Mumbai, India.

Background Human leukocyte antigens (HLA) an important host genetic factor is responsible for influencing human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) transmission and disease progression. Contributions of HLA I and II alleles have not been reported in the Indian population with respect to vertical HIV transmission. Aim In the current study we determined the frequencies of HLA class I and class II alleles in a cohort of children exposed to HIV through their mothers. Method In this exploratory study children perinatally exposed to HIV-1 who fit the study criteria and had completed 18 month follow-up were typed for HLA class I and class II alleles using polymerase chain reaction combined with sequence-specific oligonucleotides probes (PCR-SSOP) and sequence-specific primer (SSP) method. HLA typing was done in 30 positive and 60 HIV negative children along with confounding factors such as treatment regimens, viral load and CD4 count of the mother, feeding option, etc. SPSS software was used for statistical analysis and online docking tools for in-silico analysis. Results HLA-B*40 (p = 0.018) was significantly higher in negative children and was associated with protection, whereas HLA-A*01 (p = 0.05), HLA-B*37 (p = 0.032) and HLA-DRB1*09 (p = 0.017) were associated with transmission. Known protective allele HLA-B*27 was only present in negative children. Many specific haplotypes were exclusively present in the negative children or the positive ones. In-silico analysis was performed to predict the ability of HLA-B*40 to bind to antigenic peptides obtained from HIV-1 sequences in our study group. Limitations Small sample size is a concerning limitation of the study. Nonetheless this is a comprehensive study on HLA alleles in HIV exposed Indian children Conclusion Our study highlights the contribution of HLA class I and II alleles in the Indian children and further adds to understanding the immunogenetic mechanisms. These can be developed as markers for prediction of infection transmission. The observations also contribute to the database of genetic makeup of our population and can help in designing vaccine strategies.

HLA-B*13 :01 Is a Predictive Marker of Dapsone-Induced Severe Cutaneous Adverse Reactions in Thai Patients.

HLA-B*13:01 allele has been identified as the genetic determinant of dapsone hypersensitivity syndrome (DHS) among leprosy and non-leprosy patients in several studies. Dapsone hydroxylamine (DDS-NHOH), an active metabolite of dapsone, has been believed to be responsible for DHS. However, studies have not highlighted the importance of other genetic polymorphisms in dapsone-induced severe cutaneous adverse reactions (SCAR). We investigated the association of HLA alleles and cytochrome P450 (CYP) alleles with dapsone-induced SCAR in Thai non-leprosy patients. A prospective cohort study, 16 Thai patients of dapsone-induced SCARs (5 SJS-TEN and 11 DRESS) and 9 Taiwanese patients of dapsone-induced SCARs (2 SJS-TEN and 7 DRESS), 40 dapsone-tolerant controls, and 470 general Thai population were enrolled. HLA class I and II alleles were genotyped using polymerase chain reaction-sequence specific oligonucleotides (PCR-SSOs). CYP2C9, CYP2C19, and CYP3A4 genotypes were determined by the TaqMan real-time PCR assay. We performed computational analyses of dapsone and DDS-NHOH interacting with HLA-B*13:01 and HLA-B*13:02 alleles by the molecular docking approach. Among all the HLA alleles, only HLA-B*13:01 allele was found to be significantly associated with dapsone-induced SCARs (OR = 39.00, 95% CI = 7.67-198.21, p = 5.3447 × 10-7), SJS-TEN (OR = 36.00, 95% CI = 3.19-405.89, p = 2.1657 × 10-3), and DRESS (OR = 40.50, 95% CI = 6.38-257.03, p = 1.0784 × 10-5) as compared to dapsone-tolerant controls. Also, HLA-B*13:01 allele was strongly associated with dapsone-induced SCARs in Asians (OR = 36.00, 95% CI = 8.67-149.52, p = 2.8068 × 10-7) and Taiwanese (OR = 31.50, 95% CI = 4.80-206.56, p = 2.5519 × 10-3). Furthermore, dapsone and DDS-NHOH fit within the extra-deep sub pocket of the antigen-binding site of the HLA-B*13:01 allele and change the antigen-recognition site. However, there was no significant association between genetic polymorphism of cytochrome P450 (CYP2C9, CYP2C19, and CYP3A4) and dapsone-induced SCARs (SJS-TEN and DRESS). The results of this study support the specific genotyping of the HLA-B*13:01 allele to avoid dapsone-induced SCARs including SJS-TEN and DRESS before initiating dapsone therapy in the Asian population.

Association of MICA and HLA-B alleles with leprosy in two endemic populations in Brazil.

Leprosy is a prevalent disease in Brazil, which ranks as the country with the second highest number of cases in the world. The disease manifests in a spectrum of forms, and genetic differences in the host can help to elucidate the immunopathogenesis. For a better understanding of MICA association with leprosy, we performed a case-control and a family-based study in two endemic populations in Brazil. MICA and HLA-B alleles were evaluated in 409 leprosy patients and in 419 healthy contacts by PCR-SSOP-Luminex-based technology. In the familial study, analysis of 46 families was completed by direct sequencing of all exons and 3'/5'untranslated regions, using the Ilumina MiSeq platform. All data were collected between 2006 and 2009. Statistical analysis was performed using the Chi-square or Fisher's exact test together with a multivariate analysis. Family-based association was assessed by transmission disequilibrium test (TDT) software FBAT 2.0.4. We found associations between the haplotype MICA*002-HLA-B*35 with leprosy in both the per se and the multibacillary (MB) forms when compared to healthy contacts. The MICA allele *008 was associated with the clinical forms of paucibacillary (PB). Additionally, MICA*029 was associated with the clinical forms of MB. The association of MICA*029 allele (MICA-A4 variant) with the susceptibility to the MB form suggests this variant for the transmembrane domain of the MICA molecule may be a risk factor for leprosy. Two MICA and nine HLA-B variants were found associated with leprosy per se in the Colônia do Prata population. Linkage disequilibrium analysis revealed perfect linkage disequilibrium (LD) between HLA-B markers rs2596498 and rs2507992, and high LD (R2  = .92) between these and the marker rs2442718. This familial study demonstrates that MICA association signals are not independent from those observed for HLA-B. Our findings contribute the knowledge pool of the immunogenetics of Hansen's disease and reveals a new association of the MICA*029 allele.

Amino Acid Variants of HLA-DRB1 Confer Susceptibility to Dapsone Hypersensitivity Syndrome in Addition to HLA-B*13:01.

Dapsone hypersensitivity syndrome is a rare yet severe adverse drug reaction caused by dapsone, a principal drug in multidrug therapy for leprosy. HLA-B*13:01 has been identified as a strong risk factor of dapsone hypersensitivity syndrome; however, its low positive predictive value indicated that additional genetic variants may be involved in the disease development. To discover contributing genetic variants within HLA loci in addition to HLA-B*13:01, we performed a high-coverage next-generation sequencing (NGS)-based HLA typing analysis in 103 dapsone-hypersensitive and 857 dapsone-tolerant HLA-B*13:01-positive leprosy patients in a Chinese population. Five amino acid variants in high linkage disequilibrium of HLA-DRB1 were significantly associated with dapsone hypersensitivity syndrome (positions 133, 142, -17, 11, and 13). DRB1*16:02 and DRB1*15:01 tagged by these risk-conferring amino acid residues were associated at a nominal significance level. This study identifies five amino acid variants within HLA-DRB1 that are in high linkage disequilibrium and significantly associated with dapsone hypersensitivity syndrome in a Chinese population.

Dapsone-induced severe cutaneous adverse drug reactions are strongly linked with HLA-B*13: 01 allele in the Thai population.

OBJECTIVES: A previous publication in Chinese leprosy patients showed that the HLA-B*13:01 allele is a strong genetic marker for dapsone-induced drug hypersensitivity reactions, however there are no data describing whether HLA-B*13:01 is a valid marker for prediction of dapsone-induced drug hypersensitivity reactions in other ethnicities or nonleprosy patients. The aim of this study is to investigate whether there is an association between HLA genotypes and dapsone-induced severe cutaneous adverse reactions (SCARs) in Thai nonleprosy patients. PATIENTS AND METHODS: HLA-B genotypes of 15 patients with dapsone-induced SCARs (11 drug reaction with eosinophilia and systemic symptoms, 4 Stevens-Johnson syndrome/toxic epidermal necrolysis), 29 control patients, and 986 subjects from the general Thai population were determined by the reverse PCR sequence-specific oligonucleotides probe. RESULTS: The HLA-B*13:01 allele was significantly associated with dapsone-induced SCARs compared with dapsone-tolerant controls (odds ratio: 54.00, 95% confidence interval: 7.96-366.16, P=0.0001) and the general population (odds ratio: 26.11, 95% confidence interval: 7.27-93.75, P=0.0001). In addition, HLA-B*13:01 associated with dapsone-induced SJS-TEN (OR: 40.50, 95% confidence interval: 2.78-591.01, P=0.0070) and DRESS (OR: 60.75, 95% confidence interval: 7.44-496.18, P=0.0001). CONCLUSION: This study demonstrated an association between HLA-B*13:01 and dapsone-induced SCARs including Stevens-Johnson syndrome/toxic epidermal necrolysis and drug reaction with eosinophilia and systemic symptoms in nonleprosy patients. Moreover, these results suggest that the HLA-B*13:01 allele may be a useful genetic marker for prediction of dapsone-induced SCARs in Thai and Han-Chinese populations.

Drug eruptions induced by allopurinol associated with HLA-B*5801.

Allopurinol, a drug commonly used for treating gout and hyperuricemia, is a frequent cause of drug eruptions. Recent investigations suggest that HLA-BFNx015801 allele is a very strong marker for allopurinol-induced cutaneous adverse drug reactions (cADRs). In this article we report two cases of allopurinol-induced drug eruptions in patients carrying the HLA-BFNx015801 allele and review the literature on the association between HLA-BFNx015801 and allopurinol-induced cADRs based on a MEDLINE and PubMed search.

HLA-B*13:01 and the dapsone hypersensitivity syndrome.

BACKGROUND: Dapsone is used in the treatment of infections and inflammatory diseases. The dapsone hypersensitivity syndrome, which is associated with a reported mortality of 9.9%, develops in about 0.5 to 3.6% of persons treated with the drug. Currently, no tests are available to predict the risk of the dapsone hypersensitivity syndrome. METHODS: We performed a genomewide association study involving 872 participants who had received dapsone as part of multidrug therapy for leprosy (39 participants with the dapsone hypersensitivity syndrome and 833 controls), using log-additive tests of single-nucleotide polymorphisms (SNPs) and imputed HLA molecules. For a replication analysis, we genotyped 24 SNPs in an additional 31 participants with the dapsone hypersensitivity syndrome and 1089 controls and performed next-generation sequencing for HLA-B and HLA-C typing at four-digit resolution in an independent series of 37 participants with the dapsone hypersensitivity syndrome and 201 controls. RESULTS: Genomewide association analysis showed that SNP rs2844573, located between the HLA-B and MICA loci, was significantly associated with the dapsone hypersensitivity syndrome among patients with leprosy (odds ratio, 6.18; P=3.84×10(-13)). HLA-B*13:01 was confirmed to be a risk factor for the dapsone hypersensitivity syndrome (odds ratio, 20.53; P=6.84×10(-25)). The presence of HLA-B*13:01 had a sensitivity of 85.5% and a specificity of 85.7% as a predictor of the dapsone hypersensitivity syndrome, and its absence was associated with a reduction in risk by a factor of 7 (from 1.4% to 0.2%). HLA-B*13:01 is present in about 2 to 20% of Chinese persons, 1.5% of Japanese persons, 1 to 12% of Indians, and 2 to 4% of Southeast Asians but is largely absent in Europeans and Africans. CONCLUSIONS: HLA-B*13:01 was associated with the development of the dapsone hypersensitivity syndrome among patients with leprosy. (Funded by the National Natural Science Foundation of China and others.).

Frequencies of MICA alleles in patients from southern Brazil with multibacillary and paucibacillary leprosy.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which mainly affects the skin and nervous system. The disease has several clinical forms. This study investigated the MICA and HLA-B genes in 223 samples from leprosy patients and 201 samples from healthy individuals matched for age, gender and ethnical background. Of the patients, 153 had multibacillary, 45 paucibacillary and 25 indeterminate leprosy. The aim of this case-control study was to assess whether the MICA alleles influence susceptibility for leprosy or affect the subtype of the disease in a population of southern Brazil. There were significant differences in frequencies of the MICA*027 allele (4.7% vs 1.8%, P-value = 0.01, OR = 0.37; 95% CI = 0.16-0.85) between leprosy patients and controls, and of the MICA*010 (4.5% vs 1.6%, P-value = 0.05, OR = 0.35, 95% CI = 0.13-0.97) and MICA*027 alleles (4.7% vs 1.3%, P-value = 0.01; OR = 0.27; 95% CI = 0.09-0.79) between multibacillary leprosy patients and the control group. There were no significant differences in the frequency of MICA alleles between paucibacillary leprosy patients and controls. Thus, the MICA*027 allele is associated with a protective effect for leprosy per se, while the MICA*010 and MICA*027 alleles are associated with protection against multibacillary leprosy, the most severe clinical subtype.

Association of HLA-DRB1*0405 with resistance to multibacillary leprosy in Taiwanese.

Host factors play an important role in determining the immune response and development of leprosy. The human leukocyte antigen system (HLA) has repeatedly been found to be associated with the pathogenesis of leprosy. This study analyzes the polymorphism of the HLA class I and II antigens in multibacillary leprosy patients and a healthy control group to provide predictable prognostic indicators and/or a differential diagnostic for the disease. Sixty-5 multibacillary leprosy patients from Lo-Sheng Leprosarium and 190 healthy Taiwanese were used as cases and controls, respectively. A serologic method was initially used for HLA-A and HLA-B antigen determination, and sequence-based typing was later applied for HLA-DRB1 allele typing. Although no significant associations were found with HLA-A or HLA-B antigens, this study shows a strong HLA-DRB1*0405 association with resistance to multibacillary leprosy, supporting results previously reported in the literatures.

Comparative case control study of clinical features and human leukocyte antigen susceptibility between familial and nonfamilial vitiligo.

BACKGROUND: Various studies worldwide suggest that human leukocyte antigen (HLA) region may be involved in the genetic susceptibility of vitiligo but little information is available from India. AIM: To find the HLA associated susceptibility to develop vitiligo in Indian patients and to detect role of HLA in familial vitiligo. METHODS: This was a case controlled study which included all patients suffering from vitiligo over a period of one and half years. Clinical details were noted and sera collected from these patients were screened for the presence of HLA class I antibodies. The clinical features and HLA antigens were assessed and comparison was made between patients with familial and nonfamilial vitiligo. RESULTS: Out of 114 patients studied, 84 had family history and 30 had no family history. Patients with family history of vitiligo have higher chances of acquiring vitiligo if first degree relatives are affected compared to if second degree relatives are affected. Family history of vitiligo is associated with an early onset of vitiligo (< 20 years). There was no statistically significant difference in the type, stability, and severity of vitiligo in both the groups. HLA results in both the groups revealed increase in HLA A2, A11, A31, A33, B17, B35, B40, and B44 alleles while HLA A9, B13, and B53 alleles were decreased. Family history was associated with HLA A2, A28, A31, and B44 alleles. Early onset of vitiligo (< 20 years) was significantly associated with HLA A2, A11, B17, B35, and B44 alleles. The patients with severe affection (> 10% area) showed in significant association with HLA A10 and B8. CONCLUSION: Family history of vitiligo is associated with an early onset of vitiligo. There is no correlation of family history with the type of vitiligo, stability of lesions, and areas involved. Severity is not associated with family history. Apart from other alleles, alleles A2, and B44 play a significant role in vitiligo in the Indian patients.

Association of HLA-B*1502 allele and carbamazepine-induced Stevens-Johnson syndrome among Indians.

BACKGROUND: Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis are severe cutaneous reactions caused by certain drugs, including antiepileptic carbamazepine. A strong association has been reported between human leucocyte antigen (HLA)-B*1502 and carbamazepine-induced SJS in Han Chinese patients. European studies suggested that HLA-B*1502 is not a universal marker but is ethnicity-specific for Asians. AIM: To study the association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients. METHODS: Eight individuals who fulfilled the diagnostic criteria of SJS induced by carbamazepine were identified and HLA-B molecular typing was performed. HLA-B genotyping was carried out by polymerase chain reaction using sequence-specific primers. RESULTS: Out of eight patients studied for genotype, six patients were found to have the HLA-B*1502 allele. CONCLUSION: This study suggests an association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients.

Immunogenetic association in patients with antineutrophil cytoplasmic antibodies (ANCA) from Mumbai, Maharashtra, India.

Considerable genetic evidence exit for ANCA-associated vasculitis and pathogenesis. HLA A and B alleles identified serologically from 84 ANCA-positive patients were compared with 101 controls. Further subtyping were done in the 27 "pauci-immune" vasculitis patients using the polymerase chain reaction based PCR-SSOP technique and compared with controls (67). The results revealed that HLA A1 (OR=4.00; p value 2.72E-05), B17 (OR=3.38; p value 0.0008) and HLA B40 (OR=2.74; p value 0.001) were significantly increased among ANCA-positive patients when compared with the controls. Further, the molecular subtypes A*0101 (OR=5.04; p value 0.0005), B*5801 (OR=4.47; p value 0.0002) and haplotype A*0101-B*5801 (OR=4.47; p value 0.0001) were significantly increased among the autoimmune patients. The study revealed that HLA A1, B17 and B40 alleles are associated in production of antineutrophil autoantibodies and A*0101-B*5801 haplotype is significantly associated with autoimmune diseases and they may be invariably involved in disease pathogenesis in India.

HLA linked with leprosy in southern China: HLA-linked resistance alleles to leprosy.

According to the World Health Organization recommended multidrug therapy (WHO/MDT), we have carried out this study to investigate the presence of HLA-linked susceptibility or resistance to leprosy in a southern Chinese population. Sixty-nine leprosy patients and 112 healthy controls participated in the study. HLA-DR2 subtypes, HLA-B and MHC Class I chain-related A (MICA) alleles were typed at the DNA level using the polymerase chain reaction-single strand conformation polymorphism method. The frequencies of HLA-DR2-DRB1 alleles did not show any significant differences between the patient and the control groups, suggesting that the disease susceptibility was not associated with the DR2 subtypes in this southern Chinese population. On the other hand, in the multibacillary (MB) patients significantly decreased allele frequencies of HLA-B46 (0.040 in MB patients vs 0.129 in controls) and MICA-A5 (0.200 vs 0.380) were observed compared with the healthy controls. The calculated relative risk (RR) for B46 was 0.28; for MICA-A5, 0.52. In addition, on haplotype analysis the frequency of the HLA-B46/MICA-A5 haplotype was significantly decreased in the MB patients compared to controls (0.060 vs 0.233, RR = 0.22, p < 0.01). These results suggest that an HLA-linked disease-resistant gene to MB leprosy in southern China is in strong linkage disequilibrium with the HLA-B46/MICA-A5 haplotype. In other words, the resistant gene may be located near the HLA-B/MICA region and not in the HLA-DR locus.

Testing candidate genes that may affect susceptibility to leprosy.

Several statistical methods have been used to search familial data sets for marker alleles associated with the occurrence of a disease. In the present paper, a recently developed method is used to re-analyze published data on leprosy and candidate genes at the HLA loci. This new method of analysis, the randomization transmission disequilibrium test (TDT), confirmed previous conclusions that there was no significant evidence against random transmission at the HLA-A locus but significant positive association with the HLA-DR2 allele. The randomization TDT detected significant protective associations, that had not previously been found, with alleles HLA-B8 in Egyptian families and HLA-B21 (current nomenclature B x 4901, 5001-5002) in South Indian families, highlighting a major advantage of permutation tests in analyzing candidate gene loci with rare alleles. These findings provide evidence that HLA class I restricted T lymphocytes may be of protective importance in leprosy.