Influence of HLA-DR antigens on macrophage phagocytosis with live Mycobacterium tuberculosis in pulmonary tuberculosis.

Rajeswari, D.N.; Selvaraj, P.; Jawahar, M.S.; Alagarasu, K.; Raghavan, S.; Narayanan, P.R.

57 th TB Seal Campaign, The TB Association of India; 2006; 1-9.

Summary: Background: Our earlier studies revealed that while Human Leucocyte Antigen HLA-DR2 is associated with susceptibility to pulmonary tuberculosis, HLA-DR2 and –DR3 influence antibody and lymphoproliferative response to Mycobacterium tuberculosis antigens.

Objectives: The present study was aimed to understand the regulatory role played by HLA-DR antigens on the macrophage phagocytosis with live M. tuberculosis.

Methods: The study was carried out in 65 normal healthy subjects (NHS) and 66 pulmonary tuberculosis patients (PTB). Peripheral blood monocyte derived macrophages were infected with live M. tuberculosis and phagocytic index calculated. DNA isolated from lymphocytes was used for HLA-DR typing using Polymerase Chain Reaction and Sequence Specific Oligo Probes.

Results: A significantly decresed macrophage phagocytosis was observed in NHS positive for HLA-DR3 (p=0.04) and –DR10 phenotypes (p=0.00006) as compared to non-DR3 and non-DR10. However, PTB patients showed no difference between variant HLA-DR groups in the Phagocytic efficiency of macrophages. In normal subjects, among the various diplotypic combinations of HLA-DR3 and –DR10 analysed, HLA-DR2/DR3, -DR3/DR6 and –DR6/DR10 combinations are associated with decreased and –DR1/DR2 with increased phagocytosis.

Conclusion: The present study suggests that HLA-DR3 and –DR10 antigens play an important role along with other HLA-DR anigens, especially with HLA-DR2, on macrophage phagocytosis of live M. tuberculosis , a first line of defense in tuberculoimmunity.

Keywords: HLA-DR, M. tuberculosis , macrophage phagocytosis, pulmonary tuberculosis.

Back to List of publications / Home