Lymphocytotoxic antibodies & immunity in pulmonary tuberculosis

To understand whether the presence of cold reactive lymphocytotoxic antibod ies (LCA) (reactive at 15 degrees C) in the system has any effect on immuni ty to tuberculosis lymphocytotoxic antibodies to adherent cells (enriched-B cells) and non-adherent cells were studied in active-TB (n=42) and inactiv e-TB (cured) patients (n=49) and healthy controls (n=32). The plasma sample s of inactive-TB patients showed higher percentage of positivity for lympho cytotoxic antibodies (36.7%) than the active-TB patients (21.4%) and contro l subjects (18.8%). No significant difference on antibody and lymphocyte re sponse against Mycobacterium tuberculosis culture filtrate antigens was obs erved between LCA positive and LCA negative active-TB patients and normal h ealthy controls. Further, determination of HLA-DR phenotype of the patients and control subjects showed that individuals positive for lymphocytotoxic antibodies were more among HLA-DR2 positive and DR7 positive active-TB pati ents and control subjects than non-DR2 and non-DR7 subjects. The present st udy suggests that the cold reactive lymphocytotoxic antibodies may be again st B-lymphocytes and persistent for a longer time. HLA-DR2 and -DR7 may be associated with the occurrence of LCA activity. Further, the presence of LC A has no immunoregulatory role on immunity to tuberculosis.