Short tandem repeat technology has diverse applications: individual identification, phylogenetic reconstruction and chimerism based post haematopoietic stem cell transplantation graft monitoring.

BACKGROUND: Short Tandem Repeat (STR) loci are widely considered to be effective for variety of applications including forensic applications, phylogenetic reconstruction and chimerism based post Haematopoietic Stem Cell Transplantation (HSCT) graft monitoring. For each application, specific sets of STR loci are used. AIMS: In the present study, we have attempted to use same set of STR loci for varied purposes based on their efficacy and informativity. SETTINGS AND DESIGN: Population and patient based study. MATERIALS AND METHODS: We have analyzed 5 STR loci--vWA, Tho1, FES, F13 and TPOX in 1000 North Indians. All five markers were also analyzed for chimerism based graft monitoring after HSCT in 42 HLA matched pair of patient-donor to predict the outcome of transplantation. STATISTICAL ANALYSIS: The analysis was done for Hardy Weinberg equilibrium (HWE), Heterozygosity, Polymorphism information content (PIC) and Power of Exclusion and Phylogenetic assessment. RESULTS AND CONCLUSIONS: High allelic variability in term of Heterozygosity (0.68-0.76), PIC (0.66-0.74) and high Power of exclusion (0.28-0.38) indicating high forensic utility. The ensuing PC plots finely resolved three basal clusters corresponding to three geo-ethnic groups of African, Orientals, and Caucasians. In post HSCT chimerism analysis, it was found that together these markers were informative in 38 pairs (98%) and were able to predict the chimerism status successfully. There is a possibility that these STR loci along with forensic and phylogenetic importance, can predict the outcome of HSCT successfully.

Association of human leucocyte DR and DQ antigens in Crohn's disease in Asian Indians: a family study.

The pathogenesis of Crohn's disease (CD) involves an abnormal immune response to enteric bacteria in genetically susceptible individuals. There are no family studies regarding the association of CD with human leucocyte antigens (HLA) class II. In the present study, we have studied the association of HLA class II antigens in patients with CD and their first-degree relatives. Nine patients with CD and their first-degree relatives were studied. A group of 110 healthy unrelated and ethnically matched subjects were used as controls. Molecular HLA typing was done using the sequence-specific primer-based method. The transmission disequilibrium test (TDT) was used to analyze the results. A total of 65 individuals were included in the study; 52/56 first-degree relatives (92.8%) of 9 patients with CD consented to the study. The median age of patients was 40 years. When the distribution of the HLA class II antigens in patients was compared to that in controls no significant differences were observed even after applying the Yates correction. As the sample size of the population was small, the association of CD with DR and DQ alleles was further analyzed by using the TDT. Even after applying TDT, no significant association was observed. Familial aggregation of CD is uncommon in India. Crohn disease is not associated with HLA class II antigens in Indian patients. Genes of the major histocompatiblity complex are likely to contribute little to the susceptibility to Crohn disease in Indian patients.

Evidence for activation of cellular immune responses in patients with acute hepatitis E.

INTRODUCTION: Although acute hepatitis E virus (HEV) infection is known to induce IgM and IgG humoral host immune responses, little is known about occurrence of cellular responses in this infection. We looked for evidence of lymphocyte sensitization to HEV peptides in patients with acute HEV infection. METHODS: peripheral blood lymphocytes were obtained from patients with acute hepatitis E and healthy controls. Proliferation of these lymphocytes in the presence of each of seven peptides with amino acid sequences corresponding to open reading frames 2 and 3 proteins of HEV (3 and 4 peptides, respectively) were studied; no peptide was added to control wells. Proliferative responses with stimulation indices exceeding 3.0 were taken as positive. RESULTS: More patients showed reactivity to two or more HEV peptides than did controls (11/21 vs 5/22, p<0.05). Reactivity to one peptide corresponding to open reading frame 2 of HEV was more frequent in patients than in controls (7/21 vs 1/22, p<0.05). CONCLUSION: Our results show that lymphocytes of patients with acute hepatitis E show sensitization to HEV peptides. This may have significance in understanding the pathogenetic mechanisms of liver injury in this infection.