HLA-DR phenotypes and IgG, IgA and IgM antibody responses to Mycobacterium tuberculosis culture filtrate and 30 kDa antigens in pulmonary tuberculosis.

Selvaraj, P.; Raja, A ; Kurian, S.M.; Uma Devi, K.R.; Narayanan, P.R.

Current Science; 2004; 87; 771-775.

Abstract : The role of HLA-DR genetic make up on the IgG, IgA and IgM antibody response to Mycobacterium tuberculosis culture filtrate and 30 kDa antigens was studied in pulmonary tuberculosis. The study was carried out in HLA-DR typed active pulmonary tuberculosis (ATB) patients ( n = 37), inactive (cured) pulmonary tuberculosis (ITB) patients ( n = 79) and normal healthy subjects (NHS; n = 46). In ATB and ITB (cured) patients, IgG antibody (optical density at 490 nm for 1:3200 dilution) as measured by enzyme-linked immunosorbent assay was the predominant one than IgA and IgM antibodies. Increased IgG antibody titre to culture filtrate ( P = 0.03) and decreased titre to 30 kDa antigen were observed with HLA-DR1 positive ATB patients than non-DR1 (ATB) patients. Moreover, HLA-DR4- and HLA-DR6-positive ATB patients showed trends toward an increased IgG antibody response to 30 kDa antigen than HLA-DR4- and HLA-DR6-negative (ATB) patients respectively. Significantly increased IgA antibody to 30 kDa antigen was observed with HLA-DR1-positive ATB patients than non-DR1 patients ( P = 0.03). The study suggests that multiple HLA-DR molecules may regulate the IgG and IgA antibody responses to various proteins of M. tuberculosis . Moreover, HLA-DR phenotypes and increased IgG and IgA antibody titres may be useful to differentiate M. tuberculosis- infected subjects from normal subjects and cured patients with the same HLA-DR phenotypes or genetic make-up

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