Effects of isoniazid treatment on human lymphocyte proliferative response, lymphocyte subsets and natural killer cell activity.

The effect of isoniazid on proliferative response, natural killer (NK) cell activity and lymphocyte subset distribution of blood mononuclear cells (BMNC) was investigated. To evaluate the effect of treatment with isoniazid in pharmacologic concentrations, twenty healthy HIV-seronegative volunteers were randomized into two groups: one group received isoniazid tablets plus pyridoxin tablets once a day for 30 days, the other group received pyridoxin only. Blood samples were collected on day 0 and day 30. Inhibition of the PHA-induced proliferative response was demonstrated in lymphocyte cultures from isoniazid-treated volunteers (p < 0.001). However, no effect was seen on the IL-2- or antigen (PPD)-induced proliferative response or the NK cell activity of isolated BMNC. Inhibition of the PHA-induced proliferative response could not be related to changes in the distribution of CD3+, CD4+, CD8+, CD14, or CD19+ lymphocyte subsets. The effects, in vitro, were investigated by addition of isoniazid to cultures of BMNC isolated from either HIV-seroposive or HIV-seronegative donors who did not receive any treatment. We found that isoniazid did not influence the mitogen- or antigen-stimulated proliferative response or the NK cell activity.