Cold reactive lymphocytotoxic antibodies in pulmonary tuberculosis: correlation with disease activity and HLA.

Cold reactive lymphocytotoxic antibodies (LCA) are more reactive in cold than at 37 degrees C and occur following infection, immunization or vaccination and in various autoimmune diseases. In the present study, LCA activity against T and B-lymphocytes has been investigated in patients with pulmonary tuberculosis (PTB), their various clinical sub-groups and consanguineous relatives. Further, the relevance of HLA factors in LCA activity was analyzed. The sera from 144 PTB patients, 52 family contacts and 52 healthy individuals were tested for presence of LCAs by a modified two-stage NIH microlymphocytotoxicity assay. A significant increase in LCA activity against both T (32.6% vs 5.7%, P < 0.0001) and B (59.7% vs 13.4%, P < 0.0000001) cells was observed in PTB patients as compared to healthy controls. There was no correlation between serum LCA activity and sputum acid-fast bacilli status. However, only B cell LCAs revealed significant increase in parallel to disease advancement as assessed by X-ray chest examination. Further, LCA activity was more pronounced in drug responders than drug failure group of patients. No significant difference in the distribution of HLA class I and class II antigens was observed between LCA positive and LCA negative patients. However, panel cells carrying HLA-A1, -A11 and -DR3 were often found reactive in LCA positive patient sera. In household family contacts, LCAs were significantly increased only against B cells as compared to healthy controls (38.4% vs 13.4%, P < 0.01). This study suggests that Mycobacterium tuberculosis infection/exposure could account for the occurrence of LCAs in pulmonary tuberculosis and the strength of these antibodies is related to disease severity and the extent of lung involvement.

Lymphocytotoxic antibodies & immunity in pulmonary tuberculosis.

To understand whether the presence of cold reactive lymphocytotoxic antibodies (LCA) (reactive at 15 degrees C) in the system has any effect on immunity to tuberculosis lymphocytotoxic antibodies to adherent cells (enriched-B cells) and non-adherent cells were studied in active-TB (n = 42) and inactive-TB (cured) patients (n = 49) and healthy controls (n = 32). The plasma samples of inactive-TB patients showed higher percentage of positivity for lymphocytotoxic antibodies (36.7%) than the active-TB patients (21.4%) and control subjects (18.8%). No significant difference on antibody and lymphocyte response against Mycobacterium tuberculosis culture filtrate antigens was observed between LCA positive and LCA negative active-TB patients and normal healthy 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 patients and control subjects than non-DR2 and non-DR7 subjects. The present study suggests that the cold reactive lymphocytotoxic antibodies may be against 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 LCA has no immunoregulatory role on immunity to tuberculosis.

Lymphocytotoxic antibodies in patients with systemic lupus erythematosus & their household contacts.

Twenty patients with systemic lupus erythematosus (SLE) and their 51 household contacts were screened for the presence of lymphocytotoxic antibodies. A high prevalence of lymphocytotoxic antibodies (LCTAB) was observed in the patients (80% against T cells and 100% against B cells). The antibodies carried specificity for HLA-B5/35 and HLA-DR2/DR3. A high prevalence of LCTAB was also observed in contacts (55% LCTAB-T cells, 88% LCTAB-B cells) with no difference being seen between consanguineous and non-consanguineous male or female relatives.