Joint study of the associations of HLA-B and the transmembrane short tandem repeat polymorphism of MICA protein with alopecia areata shows independent associations of both with the disease.

BACKGROUND: Alopecia areata (AA) is a skin disease that produces hair loss in patches of skin. The underlying mechanism of AA is a loss of immune privilege of hair follicles, which are then attacked by natural killer (NK) cells. A previous genome-wide association study linked single nucleotide polymorphisms of the protein MHC class I chain-related A (MICA) to this disease. MICA is the ligand for the activating receptor NKG2D, expressed mainly by NK cells and CD8+ cytotoxic T cells. As the aforementioned study did not include short tandem repeats (STRs) of MICA, we decided to study these in relation to AA. AIM: To study the association of STRs with AA, alongside that of human leucocyte antigen (HLA) locus B, which is closely linked to MICA. METHODS: DNA amplicon size analysis was carried out, and HLA-B locus genomic typing was performed by PCR-sequence-specific oligonucleotide analysis. RESULTS: We observed an association between AA and both MICA*009 and HLA-B14; associations were also observed between HLA-B alleles and MICA alleles, which have both been previously found to be connected with AA, but never studied together. CONCLUSIONS: We conclude that it is important to study HLA-B and MICA together to avoid the influence of their association in experiments in which they are investigated separately.

HLA-B*14 allele predicts HIV-1 mother-to-child-transmission, in Salvador, Brazil.

BACKGROUND: Class I human leukocyte antigens, especially the molecules encoded at the B locus (HLA-B), are associated with AIDS progression risk. Different groups of HLA-B alleles have been associated to a protective effect or increasing susceptibility to HIV infection and are expressed from the earliest stages of gestation. OBJECTIVE: The aim of this study was to evaluate which variants of HLA-B are associated with the risk of HIV vertical transmission in infected pregnant women and in their offspring, in a referral center in Salvador Bahia. METHODS: We performed HLA-B genotyping in 52 HIV-infected mothers and their children exposed to HIV-1 during pregnancy (N=65) in Salvador, Brazil. We compared the HLA-B alleles frequency in mothers, uninfected and infected children, according to the use of antiretroviral prophylaxis. RESULTS: Absence of antiretroviral antenatal and postnatal prophylaxis was significantly associated with vertical transmission of HIV-1 (p=<0.01, and p=<0.01 respectively). Frequency of HLA-B*14 (29.2%, p=0.002), HLA-B*18 (16.7%, p=0.04) or HLA-B*14:1 (20.8%, p=0.01) alleles subgroups were significantly higher in HIV-1 infected children and persisted (HLA-B*14, p=0.04) even after adjusting for use of antiretroviral prophylaxis. No significant difference in expression of HLA-B alleles was observed among mothers who transmitted the virus compared to those who did not. CONCLUSIONS: Expression of HLA-B*14 allele in children exposed to HIV-1 is predictive of vertical transmission and reinforces the important role of genetics in mother-to-child transmission.

HLA-B*14 allele predicts HIV-1 mother-to-child-transmission, in Salvador, Brazil

ABSTRACT Background: Class I human leukocyte antigens, especially the molecules encoded at the B locus (HLA-B), are associated with AIDS progression risk. Different groups of HLA-B alleles have been associated to a protective effect or increasing susceptibility to HIV infection and are expressed from the earliest stages of gestation. Objective: The aim of this study was to evaluate which variants of HLA-B are associated with the risk of HIV vertical transmission in infected pregnant women and in their offspring, in a referral center in Salvador Bahia. Methods: We performed HLA-B genotyping in 52 HIV-infected mothers and their children exposed to HIV-1 during pregnancy (N = 65) in Salvador, Brazil. We compared the HLA-B alleles frequency in mothers, uninfected and infected children, according to the use of antiretroviral prophylaxis. Results: Absence of antiretroviral antenatal and postnatal prophylaxis was significantly associated with vertical transmission of HIV-1 (p = <0.01, and p = <0.01 respectively). Frequency of HLA-B*14 (29.2%, p = 0.002), HLA-B*18 (16.7%, p = 0.04) or HLA-B*14:1 (20.8%, p = 0.01) alleles subgroups were significantly higher in HIV-1 infected children and persisted (HLA-B*14, p = 0.04) even after adjusting for use of antiretroviral prophylaxis. No significant difference in expression of HLA-B alleles was observed among mothers who transmitted the virus compared to those who did not. Conclusions: Expression of HLA-B*14 allele in children exposed to HIV-1 is predictive of vertical transmission and reinforces the important role of genetics in mother-to-child transmission.

A novel HLA-B variant, HLA-B*14:02:16, discovered by amplicon-based next-generation sequencing.

HLA-B*14:02:16 differs from B*14:02:01:01 by a synonymous nucleotide substitution in codon 141.

The role of HLA-A*33:01 in patients with cholestatic hepatitis attributed to terbinafine.

BACKGROUND & AIMS: Terbinafine is an antifungal agent that has been associated with rare instances of hepatotoxicity. In this study we aimed to describe the presenting features and outcomes of patients with terbinafine hepatotoxicity and to investigate the role of human leukocyte antigen (HLA)-A*33:01. METHODS: Consecutive high causality cases of terbinafine hepatotoxicity enrolled into the Drug Induced Liver Injury Network were reviewed. DNA samples underwent high-resolution confirmatory HLA sequencing using the Ilumina MiSeq platform. RESULTS: All 15 patients with terbinafine hepatotoxicity were more than 40 years old (median = 57 years), 53% were female and the median latency to onset was 38 days (range 24 to 114 days). At the onset of drug-induced liver injury, 80% were jaundiced, median serum alanine aminotransferase was 448 U/L and alkaline phosphatase was 333 U/L. One individual required liver transplantation for acute liver failure during follow-up, and 7 of the 13 (54%) remaining individuals had ongoing liver injury at 6 months, with 4 demonstrating persistently abnormal liver biochemistries at month 24. High-resolution HLA genotyping confirmed that 10 of the 11 (91%) European ancestry participants were carriers of the HLA-A*33:01, B*14:02, C*08:02 haplotype, which has a carrier frequency of 1.6% in European Ancestry population controls. One African American patient was also an HLA-A*33:01 carrier while 2 East Asian patients were carriers of a similar HLA type: A*33:03. Molecular docking studies indicated that terbinafine may interact with HLA-A*33:01 and A*33:03. CONCLUSIONS: Patients with terbinafine hepatotoxicity most commonly present with a mixed or cholestatic liver injury profile and frequently have residual evidence of chronic cholestatic injury. A strong genetic association of HLA-A*33:01 with terbinafine drug-induced liver injury was confirmed amongst Caucasians. LAY SUMMARY: A locus in the human leukocyte antigen gene (HLA-A*33:01, B*14:02, C*08:02) was significantly overrepresented in Caucasian and African American patients with liver injury attributed to the antifungal medication, terbinafine. These data along with the molecular docking studies demonstrate that this genetic polymorphism is a plausible risk factor for developing terbinafine hepatotoxicity and could be used in the future to help doctors make a diagnosis more rapidly and confidently.

HLA-B*14:02-Restricted Env-Specific CD8+ T-Cell Activity Has Highly Potent Antiviral Efficacy Associated with Immune Control of HIV Infection.

Immune control of human immunodeficiency virus type 1 (HIV) infection is typically associated with effective Gag-specific CD8+ T-cell responses. We here focus on HLA-B*14, which protects against HIV disease progression, but the immunodominant HLA-B*14-restricted anti-HIV response is Env specific (ERYLKDQQL, HLA-B*14-EL9). A subdominant HLA-B*14-restricted response targets Gag (DRYFKTLRA, HLA-B*14-DA9). Using HLA-B*14/peptide-saporin-conjugated tetramers, we show that HLA-B*14-EL9 is substantially more potent at inhibiting viral replication than HLA-B*14-DA9. HLA-B*14-EL9 also has significantly higher functional avidity (P < 0.0001) and drives stronger selection pressure on the virus than HLA-B*14-DA9. However, these differences were HLA-B*14 subtype specific, applying only to HLA-B*14:02 and not to HLA-B*14:01. Furthermore, the HLA-B*14-associated protection against HIV disease progression is significantly greater for HLA-B*14:02 than for HLA-B*14:01, consistent with the superior antiviral efficacy of the HLA-B*14-EL9 response. Thus, although Gag-specific CD8+ T-cell responses may usually have greater anti-HIV efficacy, factors independent of protein specificity, including functional avidity of individual responses, are also critically important to immune control of HIV.IMPORTANCE In HIV infection, although cytotoxic T lymphocytes (CTL) play a potentially critical role in eradication of viral reservoirs, the features that constitute an effective response remain poorly defined. We focus on HLA-B*14, unique among HLAs associated with control of HIV in that the dominant CTL response is Env specific, not Gag specific. We demonstrate that Env-specific HLA-B*14-restricted activity is substantially more efficacious than the subdominant HLA-B*14-restricted Gag response. Env immunodominance over Gag and strong Env-mediated selection pressure on HIV are observed only in subjects expressing HLA-B*14:02, and not HLA-B*14:01. This reflects the increased functional avidity of the Env response over Gag, substantially more marked for HLA-B*14:02. Finally, we show that HLA-B*14:02 is significantly more strongly associated with viremic control than HLA-B*14:01. These findings indicate that, although Gag-specific CTL may usually have greater anti-HIV efficacy than Env responses, factors independent of protein specificity, including functional avidity, may carry greater weight in mediating effective control of HIV.

Epitopes and motifs of the HLA-B*14 allele family products and related HLA-B14 cross-reactive specificities.

The split specificities of HLA-B14 (B64, B65) are assigned to the B*14:01 (B64) and B*14:02 (B65) products only. Of the further 50 B*14 expressed products, only B*14:03 and B*14:06 are officially designated as HLA-B14. The B*14:08 product differs from B64 by a single amino acid substitution of W97R, while the B*14:53 specificity (which is a "short" B14 and neither B64 nor B65) differs from B64 by three residues (W97S, Y113H and F116Y). Comprehensive testing of B*14:08:01 cells (using 49 alloantisera with B64 or B64, B65 specificities, and five monoclonal antibodies with B65 or B64, B65 activity) showed that the B*14:08 specificity is, like the B*14:53 product, neither B64 nor B65 and appears as a "short" B14 specificity. To help understand the serological reactivity of the B*14:08 and B*14:53 products, and B64 and B65, we identified seven published epitopes (11AV, 97W, 61ICT, 116F, 131S+163T, 170RH and 420) and, by inspection, 29 motifs, that encompass one or more of B64, B65 and various HLA-B14 cross-reactive group specificities. We then considered the possession of these epitopes and motifs by the products of B*14:01 to B*14:06, B*14:08 and B*14:53. Seventeen of the 29 motifs fully complied with the one-/two-patch functional epitope concept for amino acid proximity, as determined by Cn3D software, the remainder partially complied. The nature and patterns of epitopes and motifs possessed by both B*14:08 and B*14:53 specificities supported their designation as HLA-B14 but non-B64/B65. Also that epitope 97W, with 11S or 11A, is critical for serological B64 and B65 reactivity. And conversely, that epitope 116F, and several identified motifs, are probably unimportant for HLA-B14 antibody reactivity. The previous submission that the B*14:03 specificity is HLA-B65 was compatible with its epitope/motif pattern. B*14:04 cells would also be expected to react as B65, based on its epitope/motif pattern, and not as B64 as previously implied. Also, from their epitope/motif patterns, and external serological information, it is probable that the B*14:05 and B*14:06 specificities will both appear as "short" HLA-B14, non-B64/B65. Several epitopes and motifs encompassed a range of HLA-B specificities included in the serological HLA-B14 cross-reactive group, thus supporting these original serological findings.

The new HLA-B*50:51 allele was generated by intralocus recombination between B*50:01:01:02 and B*14:02:01.

The new B*50:51 allele was found in 3 Caucasians from Southern Spain.

Full-length sequences of 3 HLA-B alleles, B*07:05:01:01, B*14:01:01 and B*18:02, confirmed by cloning and sequencing.

Full-length sequences of HLA-B*07:05:01:01, B*14:01:01 and B*18:02, confirmed by cloning and sequencing in Chinese donors.

Identification of HLA-B*14:41N in a NMDP Hispanic donor, selected for a patient of The Unrelated Mexican Donor Registry-DONORMO program in Mexico.

The B*14:41N allele was identified in a The National Marrow Donor Program (NMDP) Hispanic donor typed by our Mexican Registry-DONORMO.

Associations of host genetic variants on CD4⁺ lymphocyte count and plasma HIV-1 RNA in antiretroviral naïve children.

BACKGROUND: CD4 T-lymphocyte (CD4) counts and HIV plasma RNA concentration (RNA) are 2 key HIV disease markers. The complex interplay between virus and host genetics may contribute to differences in viral set point and CD4 status. Determining the effects of host genetic variation on HIV disease markers is often complicated by the use of antiretroviral therapy. In this study, the association between genetic variants and baseline HIV RNA and CD4 counts was examined in a large cohort of antiretroviral naïve children. METHODS: Specimens from 1053 HIV-infected children were screened for single nucleotide polymorphisms in 78 regions from 17 genes. Linear regression with a robust variance estimator was used to test the association between genetic markers with HIV RNA and CD4 count, controlling for age, race/ethnicity and study. False discovery rate (FDR) controlling was used to adjust for multiple testing. RESULTS: The study population was 60% black, 26% Hispanic and 13% white; median age 2.35 years; 55% female. Baseline median CD4 count was 780/mm; median log10 HIV RNA was 5.17 copies/mL. For analyses of the associations of genetic makers with baseline CD4 count, 6 HLA and 4 additional markers exhibited P < 0.05, but none met the criteria for statistical significance with FDR controlled at 0.05. For baseline HIV RNA, HLA DRB1*15, DRB1*10, B-27/57, B-14, Cw-8, B-57 were statistically significant with FDR controlled at 0.05. CONCLUSIONS: These results provide strong evidence that HLA DRB1*15, DRB1*10, B-27/57, B-14, Cw-8, B-57 are associated with HIV RNA and play a role in HIV pathogenesis in infected children.

2B4+ CD8+ T cells play an inhibitory role against constrained HIV epitopes.

Cytotoxic T cells play a critical role in the control of HIV and the progression of infected individuals to AIDS. 2B4 (CD244) is a member of the SLAM family of receptors that regulate lymphocyte development and function. The expression of 2B4 on CD8+ T cells was shown to increase during AIDS disease progression. However, the functional role of 2B4+ CD8+ T cells against HIV infection is not known. Here, we have examined the functional role of 2B4+ CD8+ T cells during and after stimulation with HLA B14 or B27 restricted HIV epitopes. Interestingly, IFN-γ secretion and cytotoxic activity of 2B4+ CD8+ T cells stimulated with HIV peptides were significantly decreased when compared to influenza peptide stimulated 2B4+ CD8+ T cells. The expression of the signaling adaptor molecule SAP was downregulated in 2B4+ CD8+ T cells upon HIV peptide stimulation. These results suggest that 2B4+ CD8+ T cells play an inhibitory role against constrained HIV epitopes underlying the inability to control the virus during disease progression.

Longer survival associated with HLA-A*03, B*14 among 212 hemochromatosis probands with HFE C282Y homozygosity and HLA-A and -B typing and haplotyping.

BACKGROUND: Human leukocyte antigen (HLA) haplotypes may influence iron phenotypes in patients with HFE hemochromatosis and could affect survival. METHODS: We tabulated general characteristics of HLA-A and -B types and haplotypes of HFE C282Y/C282Y probands diagnosed in medical care and analyzed these data to identify HLA survival modifiers. RESULTS: There were 212 probands (130 men, 82 women). Mean follow-up was 12.0 ± 6.4 yr (0.1-41.2 yr; 34 deaths). HLA-A*03 was more prevalent in men (76.9% vs. 61.0% women; P = 0.0129); 35.4% of men and 29.3% of women had A*03, B*07; and 7.7% of men and 8.5% of women had A*03, B*14. Twenty-three probands had cirrhosis; none had A*03, B*14. Positivity for A*03 or A*03, B*07 was not a significant predictor or modifier of survival. In multiple regression analyses, A*03, B*14 predicted longer survival (P = 0.0004). Kaplan-Meier analysis confirmed longer survival in probands with A*03, B*14 (P = 0.0199, log-rank test). After excluding the 23 non-A*03, B*14 probands with cirrhosis, survival of probands with A*03, B*14 was still greater than that of probands without A*03, B*14 (P = 0.0254; log-rank test). Twenty-four years after diagnosis, cumulative survival of probands with and without A*03, B*14 was 100% and 58%, respectively. The percentage of deaths due to iron overload was lower in probands with A*03, B*14 (0% vs. 21.9%; P = 0.0392). CONCLUSIONS: In hemochromatosis probands with HFE C282Y/C282Y, survival was longer in those with HLA-A*03, B*14. Earlier age at diagnosis and less severe iron overload in probands with A*03, B*14 could explain this difference.

Disparate folding and stability of the ankylosing spondylitis-associated HLA-B*1403 and B*2705 proteins.

OBJECTIVE: To investigate the folding, assembly, maturation, and stability of HLA-B*1402 and B*1403, which differ by 1 amino acid change and are differentially associated with ankylosing spondylitis (AS), and to compare these features with those of B*2705. METHODS: Stable transfectants expressing B*1402, B*1403, and B*2705 were used. Folding rates were estimated from the ratio of unfolded heavy chains to folded heavy chains that had been immunoprecipitated with specific antibodies in pulse-chase experiments. Heavy chain misfolding was measured as the half-life of endoglycosidase H (Endo H)-sensitive beta2-microglobulin-free heavy chains. Maturation/export rates were measured by acquisition of Endo H resistance. Association with calnexin or tapasin was analyzed by coprecipitation with chaperone-specific antibodies, and surface expression was estimated by flow cytometry. Thermostability of HLA-peptide complexes was assessed by immunoprecipitation after incubation at various temperatures. Heavy chain expression was quantified by Western blotting. RESULTS: The folding rates of B*1402 and B*1403 were similar, and both were faster and more efficient than B*2705, but some unfolded heavy chains from both B14 subtypes remained in the endoplasmic reticulum (ER) with a long half-life. The export rates of B*1402 and B*1403 were slow, and the heterodimers partially dissociated after exiting the ER, as revealed by significant amounts of Endo H-resistant and surface-expressed free heavy chains. Both interaction with tapasin and thermostability were higher for B*2705 than for B*1402 and higher for B*1402 than for B*1403, suggesting that the repertoires of the B*1402-bound peptide and especially the B*1403-bound peptide were less optimized than that of B*2705. CONCLUSION: Our results indicate that the folding, maturation, and stability of B*1403 differ more from B*2705 than from B*1402. Thus, these features cannot account for the fact that only the 2 former allotypes are associated with AS.

HLA association is different in children and adults with severe acquired aplastic anemia.

BACKGROUND: Severe aplastic anemia (SAA) is defined as pancytopenia caused by bone marrow failure. The pathogenesis of SAA is thought to involve autoimmune processes. Increased susceptibility to autoimmunity has been shown to be associated with several different HLA alleles. In SAA, few large studies based on data mainly from adults describe a positive HLA correlation with HLA-DR2 (DRB1*15) and HLA-B14. PROCEDURE: This study explored the HLA constitution of 181 children with SAA who were enrolled in the prospective multi-center study SAA94 between January 1994 and January 2002. The control group consisted of 303 healthy individuals of comparable demographic background. Allelic frequencies between patients and controls are compared using Fisher's exact test. RESULTS: In our pediatric cohort, we describe a positive association with HLA-B14 (P = 0.0039), but no association of HLA-DR2 with SAA. CONCLUSION: HLA associations appear to be different in children and adults with SAA. This might point towards a difference in pathophysiology between at least part of the children and adults.

Human leukocyte antigen and esophageal cancer in the northwestern region of Iran.

Esophageal squamous cell carcinoma is the 6th most commonly occurring cancer worldwide. A relationship between HLA A1 and B40 and esophageal cancer was described in patients examined in China. The aim of this study was to investigate the relation of HLA class 1 and esophageal carcinoma in the northwestern region of Iran. Using specific monoclonal antibodies, different human leukocyte antigens (HLA) were quantified in 100 patients suffering esophageal carcinoma in Tabriz, a major city located in the Northwestern region of Iran. These data were compared to those of 100 healthy matched individuals as a control group from the same region. HLA B14 and A24 were increased and showed statistically significant correlation in squamous cell carcinoma. These findings may also indicate the association between genetic factors and esophageal carcinoma. Further studies are suggested for detecting correlation of HLA and esophageal carcinoma in other regions.

HLA-dependent hypersensitivity to nevirapine in Sardinian HIV patients.

BACKGROUND: Hypersensitivity reaction to nevirapine, which in some cases can be fatal, shows a higher prevalence in Sardinia in comparison with other Italian regions. OBJECTIVE: This study demonstrates that hypersensitive reaction to nevirapine in Sardinian HIV-infected patients is associated with the HLA Cw8-B14 haplotype. These two HLA class I antigens are in strong linkage disequilibrium in the Sardinian population. METHODS: Forty-nine Sardinian HIV-positive patients treated with nevirapine were studied. Thirteen (26%), developed a hypersensitive reaction thus requiring the drug to be discontinued. HLA class I and II molecular typing was performed in both nevirapine-hypersensitive and nevirapine-tolerant patients. To avoid biased representation of the allele frequencies in the two groups of treated patients, molecular typing was also performed in 82 HIV-positive patients who had not been treated with nevirapine. RESULTS: Considerable overlap was observed for the clinical, immunological and demographic characteristics of the 13 hypersensitive patients and 36 tolerant patients. Clinical parameters included viral load, status of HIV infection, CD4 and CD8 cell counts, hepatitis C virus/hepatitis B virus co-infections. Forty-six percent (6/13) of the nevirapine-hypersensitive subjects had the HLA-Cw8 and HLA-B14(65) antigens compared with 5% (2/36) of the nevirapine-tolerant group (P = 0.004; Pc = 0.05). CONCLUSION: In agreement with other recent reports, the utility of HLA typing in HIV patients to identify genetic factors that may confer susceptibility to drug-induced hypersensitive reaction was confirmed. A careful choice of antiretroviral therapy in susceptible individuals should significantly reduce the risk of severe hypersensitive reaction.

HLA-A and HLA-B distribution in Toto - a vanishing sub-Himalayan tribe of India.

The frequency of HLA-A and HLA-B locus alleles was studied by using polymerase chain reaction-based sequence-specific primer method in a very primitive and vanishing sub-Himalayan Indian Tribe, the Toto population of North Bengal. The Toto, a Mongoloid tribe with a population size of 1172 reside only in the Totopara of Jalpaiguri district of North Bengal. We studied 40 individuals and observed some high frequency alleles when compared to other Indian tribal, non-tribal, and major world populations. Particularly, the frequency of HLA-B14 was 32.5% in the Toto population, the highest known frequency reported in any population in the world. This indigenous tribal population may harbour novel HLA alleles and unique haplotypes which extensive HLA genotyping will help to reveal, and thus further our understanding of their genetic admixture and migration patterns.