Effect of sulphasalazine on antibody response to oral antigen.

Cholera toxin was orally administered to mice concurrently receiving sulphasalazine (SASP) dissolved in L-lysine, or a control substance (L-lysine alone). Circulating antibodies to cholera toxin of IgM, IgG and IgA class were determined by direct ELISA at day 7, 14, 21 and 28. Although both groups made a significant antibody response to the antigen, mice receiving SASP tended to produce lower levels. These were significant for IgA on day 21 (P = 0.013), and for days 7-28 (P = 0.009), and 14-28 (P = 0.007). Overall, considering all antibody classes together from day 7 to 28, there was a significant effect in the SASP treated group (P = < 0.04). It appears that SASP exerts a mild immunomodulatory effect on the mucosal immune system. Further work is obviously required to substantiate these findings. The effect on the gut mucosal immune system of a drug known to ameliorate rheumatoid arthritis may offer an insight into the aetiopathogenesis of this disease.