U. Shankarkumar

Cytolytic T Lymphocytes (CTLs) from HIV-1 Subtype C–Infected Indian Patients Recognize CTL Epitopes from a Conserved Immunodominant Region of HIV-1 Gag and Nef

Analysis of the human immunodeficiency virus type 1 (HIV-1) cytolytic T lymphocyte (CTL) epitopes recognized by the targeted population is critical for HIV-1 vaccine design. Peripheral blood mononuclear cells from 47 Indian subjects at different stages of HIV-1 infection were tested for HIV-1 Gag-, Nef-, and Env-specific T cell responses by interferon (IFN)- gamma enzyme-linked immunospot (ELISPOT) assay, using pools of overlapping peptides. The Gag and Nef antigens were targeted by 83% and 36% of responders. Five immunodominant regions, 4 in Gag and 1 in Nef, were identified in the study; these regions are conserved across clades, including the African subtype C clade. Three antigenic regions were also found to be recognized by CTLs of the study participants. These regions were not identified as immunodominant regions in studies performed in Africa, which highlights the importance of differential clustering of responses within HIV-1 subtype C. Twenty-six putative epitopes--15 Gag (10 in p24 and 5 in p17), 10 Nef, and 1 Env (gp 41)--were predicted using a combination of peptide matrix ELISPOT assay and CTL epitope-prediction software. Ninety percent of the predicted epitopes were clustered in the conserved immunodominant regions of the Gag and Nef antigens. Of 26 predicted epitopes, 8 were promiscuous, 3 of which were highly conserved across clades. Three Gag and 4 Nef epitopes were novel. The identification of conserved epitopes will be important in the planning of an HIV-1 vaccine strategy for subtype C-affected regions.

Evidence for novel DRB1*15 allele association among clinically definite multiple sclerosis patients from mumbai, india

Multiple sclerosis (MS) is a clinically heterogeneous demylinating disease and an important cause of acquired neurologic disability. MS has been reported from different regions of India and its infrequency has been attributed to have genetic implications. Further, a high incidence of MS and its human leukocyte antigen B12 (HLA-B12) associations have been reported among highly inbred Parsi population from Mumbai. However, consistent HLA associations have not been reported from India. We analyzed the HLA-B, -Cw, and -DRB1 allele associations among 23 clinically definite Western Indian non-Parsi MS patients and compared them with 146 ethnically matched clinically normal individuals. HLA serologic (A, B, and Cw) as well as molecular (DRB1) typing methodology was followed. The study revealed a significant increase of HLA-A11 (24% vs. 13%; OR = 2.6; EF = 0.14; 95%CI = 1.1-3.05), B16 (4.3% vs 0.3%; OR = 13.8; EF = 0.03; 95% CI = 1.19-134.44), Cw7 (15.2% vs 3.7%; OR = 5.46; EF = 0.12; 95% CI = 0.944-17.86), and DRB1*15 (21.7% vs 2.2%; OR = 16.15; EF = 0.19; 95% CI = 1.33-68.64). Further molecular subtyping of HLA-DRB1*15 among the patients revealed two novel alleles, DRB1*1506 (20%) and DRB1*1508 (30%), along with the commonly reported DRB1*1501 (50%) for the first time in MS patients that were hitherto unidentified from other parts of India and world as well. This study reveals that there is a complexity of the genetic susceptibility to MS in different populations studied and reported.

Human leukocyte antigen allele associations in type-1 autoimmune hepatitis patients from western India.

Abstract Background and Aims:  The immunogenetic basis of autoimmune diseases has become more and more evident. We have analyzed the human leukocyte antigen (HLA) associations with type‐1 autoimmune hepatitis (AIH) among patients from western India.

Chronic synovitis and HLA B27 in patients with severe haemophilia

Chronic synovitis affects about 10% of patients with severe haemophilia in India. This disease has some features in common with ankylosing spondylitis, which has been linked to HLA B27. We therefore aimed to test whether there is an association between HLA B27 and chronic synovitis. We studied 473 patients with severe haemophilia (33 of whom had chronic synovitis), and 1175 healthy controls using a standard serological technique and the reverse line strip assay. 64% (21 of 33) of patients with haemophilia and chronic synovitis were positive for HLA B27, compared with 5% (23 of 440) of those with severe haemophilia, but not chronic synovitis (odds ratio 31.6 [95% CI 9.28-39.38], p<0.0001), and 9% (100 of 1175) of healthy controls (18.81 [9.6-27.7], p<0.0001). We conclude that there is a strong association between HLA B27 and chronic synovitis in Indian patients with severe haemophilia and screening in this population could allow treatment and prevention of the complication.

HLA A*02 allele frequencies and B haplotype associations in Western Indians

The population of Western India is described as Australoid or Proto-Australoid elements with admixture from Caucasian, Mongoloid, and Aryan races. We investigated the frequencies of human leukocyte antigen (HLA) A*02 alleles and their B* allele haplotype associations among 664 healthy unrelated Western Indians. Fifty-one of 204 serologically typed A2 individuals were analyzed for 56 molecular A*02 subtypes using high resolution polymerase chain reaction-reverse line strip-sequence-specific oligonucleotide hybridization (PCR-RLS-SSOP). A total of seven different A*02 alleles were identified, A*02011 (16%), A*0203 (16%), A*0205 (2%), A*0206 (2%), A*0211 (52.9%), A*0222 (4%), and A*0236 (8%). The most common HLA B allele associated with A*02 was B*40. Among the 42 subtypes HLA B*4006 (37.22%) was the most frequent subtype. HLA A*0211 was highly frequent in this population, A*0206 and A*0203 are common alleles observed among Asian populations, whereas A*0205 occurs in Caucasians and Africans and A*0222 has been observed among Hispanics. A*0236 has been observed among the western Indians exclusively. Most of the HLA A*02 subtypes observed were associated with B*4006 haplotype, although A*0236 was with B*0702 or B*1302 among the western Indians. The prevalence of A*0211 at high frequencies, A*0222, A*0236 novel alleles along with A*02 related haplotypes, demonstrate a substantial heterogeneity, which may be a consequence of founder effect, racial admixture, or selection pressure due to environmental factors.

Common human leucocyte antigen haplotypes in Indians – its implications in finding unrelated compatible bone marrow donors

Summary All over the world there have been efforts to make unrelated stem cell registries to cater for patients who do not have a compatible family donor and are in need of allogenic stem cell transplantation. Donors of Indian origin are poorly represented all these registries. Approximately 10 million Indians live outside India, and a substantial number of them live in the developed West. Hence when some of these patients of Indian origin need unrelated stem cell donor, they search the available National Marrow Donor Program (NMDP) registry database and invariably do not get a human leucocyte antigen (HLA) matched donor. They come to India, where a haphazard search for the donor ensues and it invariably ends in failure. Hence, we have compiled the data of our laboratory and other published reports in population HLA studies from India and abroad to show several common haplotypes from these studies. It is hoped that this will give the busy clinician an idea whether a search for prospective unrelated stem cell donor for an Indian patient is likely to succeed or not.

Defining the allelic variants of HLA A19 in the western Indian population

The population of western India is described as Australoid or proto-Australoid (elements) with Indo-Aryan racial admixture. The present study was undertaken to investigate the genetic diversity of human leukocyte antigen (HLA A19) in Western Indians, and to determine the frequency distribution of its molecular subtypes at the population level. The study revealed a high occurrence of A*3303 (56%) in this population along with other common oriental alleles. A*33 has been commonly observed in Asian Indians (18.1%), Hanza-Burush (15.7%), Punjabis (13.9%), and Japanese (11.2%) populations. A*33 has been reported with low frequencies among the Australasians, East European (Czech), North African (Noba), and Eastern Europeans (Slovenian). Significantly we observed a low frequency of A*29 and A*74 when compared with other populations among the A19 repertoire. Prevalence of HLA A*3303 at very high frequencies among Western Indians may be a consequence of the founder effect, racial admixture, or selection pressure due to environmental factors among this population.

HLA Antigen Distribution in Maratha Community from Mumbai, Maharastra, India

Abstract Two hundred and eighty nine unrelated Marathas residing in Mumbai, Maharastra, (Western India) were studied for HLA A, B, C and DR locus antigen profiles. The HLA antigen maximum likelihood gene frequencies of HLA A1, A2, A9 (24), A11, A19 (33), B5, B7, B35, B40 (61), Cw3, Cw6, DR2, DR5, DR7, DQ1 and DQ2 were increased while that of HLA A3, A10 (26), A36, B8, B13, B16 (38), B18, B21, B22 (55), B53, B73, Cw5, Cw7, DR3, DR4, DR9, and DQ3 were decreased in the Marathas. HLA antigens A25 (10), B14, B39 (16), B54 (22), B56 (22), B58 (17) and Cw8 were not identified in the present investigation. Two Locus haplotype analyses revealed the presence of A10-B8, A1-B17, A24-B52, B5-Cw9, B13-Cw3, B15-Cw2, B35-Cw4, DR2-DQ1, DR5-DQ3 and DR1-DQ9 haplotypes with positive linkage disequilibrium among the marathas. Haplotype A2- B12 was the only haplotype identified in negative linkage disequilibrium. The observed maximum likelihood gene frequencies, haplotype frequencies and linkage disequilibrium in Marathas suggest the influence of genetic drift caused by selection, geography and culture. Further the study reveals that the Hindu population of India cannot be considered as a single panmictic population due to vast allelic diversity and immense heterozygosity in haplotypes.

Autoantibody profile and other immunological parameters in recurrent spontaneous abortion patients

Background: An autoimmune cause and related immunological alterations resulting in recurrent spontaneous abortion (RSA) have been suggested in patients with unknown etiology. Materials and Methods: This study evaluated the autoantibody profile and other immunological parameters among RSA patients and normal pregnant women from Mumbai western India. Fifty RSA patients with unknown cause and greater than three consecutive abortions along with 50 normal pregnant women were studied for various auto antibodies such as ANA, anti-dsDNA, ANCA, AECA, 2 micro globulin, anti-HLA antibodies and ACLA using immunofluorescence microlymphocytotoxicity and ELISA. Immunological parameters such as HLA class I monoclonal antibody expression, CD3 (T cell), CD19 (B cell), and CD56 (NK cell) were estimated by flow cytometry. Results: The results revealed 34% positivity of all auto antibodies tested among patients. ANA(12%), ANCA (20%), AECA (24%), ACLA (8%), anti-dsDNA(0%), β2 microglobulin (14%), and anti-HLA antibodies(10%) among RSA patients were identified. An increased expression of HLA class I specific monoclonal antibody (10%) with HLA A3 (16%) specificity were found to correlate with shared HLA alleles among the RSA couples. Among normal pregnant (control) group ANA (2%), ANCA (2%), AECA (3%), ACLA (4%) and increased expression of CD56 with reduced HLA class I monoclonal were observed. Conclusion: Our findings suggest a possible role of various autoantibodies along with the related immunological parameters underlying RSA.

HLA-B27 allele diversity in Indians: impact of ethnic origin and the caste system.

Abstract HLA-B27 is a serological specificity which encompasses an increasing number of subtypes that show varied racial/ethnic prevalence in the world. Here, data from 5129 Indians (4500 population and caste; 629 tribal) is compiled from the literature. In addition, HLA-B27 subtyping of 58 positive individuals from Maharastra is presented. Analysis revealed an increased B27 antigen frequency among the north Indian groups (>5%) compared to the south Indian groups (<5%). HLA-B27 subtyping identified B*2704 (34.48%), B*2705 (36.2%), B*2707 (15.51%), B*2708 (10.34%) and B*2714 (3.44%) alleles in the population groups from Maharastra, but these differed in their distribution among the caste and tribal groups studied. The study showed that more extensive subtyping in other Indian caste groups will be necessary to resolve the evolutionary implications of HLA-B27 subtypes and their relationship to disease association in the Indian context.