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 HLADR6-
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
