The present study describes the immune status of 41 patients with rheumatoid arthritis from India. The results showed a high level of immunoglobulins, normal levels of C3, less proportion of seropositivity (54%) than that reported from the west and 26% having antinuclear antibody in their serum. T lymphocyte proportion in the blood was found to be low in acutely ill patients only. Mantoux and streptokinase-streptodornase skin tests for delayed hypersensitivity were positive only in about 50% of that of controls. However, all the patients could be sensitized to DNCB. For testing the humoral antibody response TAB vaccine was given. The levels of antibody produced against O and H antigens of "Salmonella typhi" were comparable in patients and controls. However, the level of IgM rose significantly in the patients in comparison to that of controls. The cause of this, at least partially, was found to be due to a very significant rise of rheumatoid factor after TAB vaccine in the patients. Also 3 out of 8 patients converted to a seropositive state after TAB vaccination. Controls did not show the development of rheumatoid factor.