Tumour necrosis factor alpha (-238 and -308) and beta gene polymorphisms in pulmonary tuberculosis: haplotype analysis with HLA-A, B and DR genes.

SETTING: A study of tumour necrosis factor alpha and beta (TNFalpha and beta) gene polymorphism and haplotype analysis with HLA in pulmonary tuberculosis. OBJECTIVE: To determine whether TNFalpha (-238 and -308) and TNFbeta (Nco I polymorphism in intron 2) genes either alone or in combination with human leucocyte antigens (HLA) as haplotypes afford susceptibility or resistance to pulmonary tuberculosis as well as bacteriological relapse of the disease. DESIGN: Tumour necrosis factor alpha -238, -308 (TNFalpha -238, -308) and TNFbeta (Nco I) gene polymorphisms were carried out in HLA-A,B and DR typed pulmonary tuberculosis patients (n=210) and 120 normal healthy control subjects. RESULTS: No difference in the genotype frequencies of TNFalpha-238 and -308 and TNFbeta was seen between control subjects and pulmonary tuberculosis patients. Of the HLA-TNF haplotypes analysed, the infrequent allele (A) of TNFalpha238 was in strong linkage disequilibrium with HLA-A1 (P corrected: Pc=0.001), B17 (Pc<0.0001) and DR7 (Pc=0.01) in control subjects and with B17 (Pc<0.0001) in pulmonary tuberculosis. The infrequent allele 2 of TNFalpha-308 and the infrequent allele 2 of TNFbeta were in strong linkage disequilibrium with HLA-B21. An increased haplotype frequency of HLA-B17-TNFalpha-238/A (P=0.05), B17-TNFalpha308/2 (P=0.03) and B17-TNFalpha308/2 (P=0.01) was observed in bacteriological relapse patients than quiescent patients. CONCLUSION: The present study suggests that TNFalpha (-238 and -308) and TNFbeta gene variants are not associated independently with the susceptibility to pulmonary tuberculosis. However, in combination with the HLA genes/gene products such as HLA-A1, B17, B21 and DR7, the TNFalpha and beta genes as haplotypes are associated with protection against the disease as well as an increased susceptibility to bacteriological relapse.

HLA-DR2 subtypes & immune responses in pulmonary tuberculosis.

BACKGROUND & OBJECTIVES: HLA-DR2 has been shown to be associated with the susceptibility to pulmonary tuberculosis and altered antibody and lymphocyte response in pulmonary tuberculosis. In the present study, the influence of DR2 subtypes on antibody titre and lymphocyte response to Mycobacterium tuberculosis culture filtrate antigens (10 micrograms/ml) was studied in 22 patients with active pulmonary TB (ATB), 50 inactive (cured) TB (ITB) patients and 36 healthy control subjects. METHODS: HLA-DR2 gene was amplified by polymerase chain reaction (PCR) and dot-blotted. Genotyping of DRB1*1501, *1502, *1503, *1601 and *1602 was carried out using sequence specific oligonucleotide probes (SSOPs) and detected by chemiluminescence method. Antibody titre as well as lymphocyte response to M. tuberculosis antigens were measured by enzyme linked immunosorbent assay (ELISA) and lymphocyte transformation test (LTT) respectively. RESULTS: The allele frequency of DRB1*1501 was significantly increased in pulmonary tuberculosis patients as compared to controls (P < 0.05). No marked difference in the antibody titre and lymphocyte response to M. tuberculosis antigens was observed between the DRB1 *1501, *1502 and *1503 positive or negative controls, ATB and ITB patients. DRB1 *1501 and *1502 positive as well as negative ATB patients showed a higher antibody titre as compared to controls and ITB patients. ITB patients with *1502 showed a higher lymphocyte response as compared to *1502 positive controls (P < 0.001) and ATB patients (P < 0.05). Similarly, an increased lymphocyte response was observed in *1501, and *1503 negative ITB patients compared to *1501 and *1503 negative controls and ATB patients. INTERPRETATION & CONCLUSION: The present study revealed that DRB1 *1501 may be associated either alone or with other DR2 alleles, with the susceptibility to pulmonary tuberculosis. None of the DR2 alleles influenced the antibody and lymphocyte response to M. tuberculosis culture filtrate antigens. This suggested that HLA-DR2 gene/gene products as a whole may influence the immune response in pulmonary tuberculosis.

A tale of three diseases of the bone.

Paget's disease is a relatively rare disorder of the bone with only a few reports and case series observations from India. Hypocalcaemia is rare in Paget's disease, usually occurring as a consequence of therapy with bisphosphonates. We report a 65-year-old woman with Paget's disease who had hypocalcaemia secondary to vitamin D deficiency. On further evaluation, she also had severe osteoporosis. How vitamin D deficiency affects the diagnosis and monitoring of Paget's disease and the relationship between the three diseases are discussed. This case illustrates an interesting situation with abnormal bone turnover, remodelling and mineralisation in the form of Paget's disease with osteomalacia and osteoporosis.

Longitudinal analysis of B cell repertoire and antibody gene rearrangements during early HIV infection.

In chronically HIV infected individuals, a number of functional B cell abnormalities have been described. However, the immediate changes that occur in the B cell compartment following viral exposure and how they affect the long-term course of infection are not well understood. We report the longitudinal analysis of B cell repertoires during early infection in untreated and treated individuals receiving highly active antiretroviral therapy (HAART). Analysis was based on IgG heavy chain gene utilization and CDR3 length measurement and relationship with CD4/CD8 counts, viral load, and total serum IgG, and anti-HIV antibodies levels. Repertoires were assessed at baseline and at weeks 2, 4, 12, 24, and 72 after initiation of therapy. The findings indicate a stable peripheral B cell repertoire during the first 72 weeks following infection, particularly in the HAART treated patients. A modest association between B cell repertoire integrity and viremia levels as well as treatment was detected.

Pharmacogenomic analysis of interferon receptor polymorphisms in multiple sclerosis.

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system characterized by progressive neurological dysfunction. No curative therapy is currently available, and approximately 80-90% of afflicted individuals are ultimately disabled. Interferon beta (IFNbeta) has been shown to decrease clinical relapses, reduce brain disease activity, and possibly slow progression of disability. However, the overall effect of treatment is partial and a substantial number of patients are considered poor or nonresponders. For this report, we tested the pharmacogenomic effects of eight polymorphisms in the interferon receptor genes (IFNAR1 and IFNAR2) in a group of 147 patients undergoing open-label IFNbeta therapy. Overall, no significant differences in the distribution of responders and nonresponders, classified based on prospectively acquired primary and secondary clinical end points, were observed when stratified by any of the studied IFNAR gene polymorphisms. A trend detected with a single nucleotide polymorphism SNP 16469 (A/T) located at the third intron of the IFNAR1 gene, suggesting modest association with relapse-free status, will require confirmation in an independent data set. In addition, no significant association was observed of any of the IFNAR gene polymorphisms with susceptibility to MS, as studied by a family-based association analysis.