HLA-DR2 phenotype and circulating immune complex level in pulmonary tuberculosis.

Sunil Mathan Kurian; Selvaraj, P.; Uma Sriram; Chandra, G.; Narayanan, P.R.

Biomedicine; 2000; 20; 282-287.          

Our earlier studies revealed that Human Leucocyte Antigen -DR2 (HLA-DR2) is associated with the susceptibility to pulmonary tuberculosis (PTB). Since, antigen-antibody complexes play a role in the immunopathogenesis, in the present study, we have attempted to find out whether HLA-DR2 influence the circulating immune complex (CIC) level in PTB. Circulating immune complex levels were measured (using Polyethylene Glycol precipitation method) in normal healthy laboratory volunteers (n=19) as control subject and active pulmonary-TB patients (ATB) (n=28). Significantly increased CIC levels were seen in ATB patients than the laboratory volunteers (P<0.02). Moreover, HLA-DR2 positive patients showed a significantly (P<0.01) increased immune complex level compared to HLA-DR2 positive healthy control subjects. Non-DR2 (DR2 negative) patient and control subjects showed similar immune complex level. Among the HLA-DR2 positive and -DR2 negative patients, a trend towards an increased CIC level was seen in HLA-DR2 positive ATB patients; however this was not significant. The present study suggests that increased circulating immune complex levels in ATB patients may be detrimental to the lung. Moreover, HLA-DR2 gene/gene products may play a role in augmenting the CIC level in pulmonary-TB. This inturn may be associated with severity of the disease.

Key words : HLA-DR2, PEG, Immune complex, pulmonary tuberculosis patients

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