THE EFFECT OF SULFASALAZINE ON NEUTROPHIL SUPEROXIDE GENERATION IN RHEUMATOID-ARTHRITIS

The production of superoxide by the peripheral blood neutrophils of 19 patients with active rheumatoid arthritis was measured during treatme nt with sulphasalazine (SASP). The response to drug treatment was dete rmined by change in plasma viscosity, CRP, early morning stiffness and articular index over a 10-point scale. Of the 19 patients studied, ei ght were considered to have responded well to SASP and seven to have r esponded poorly or not at all. Over the treatment period, plateau leve ls of superoxide production fell in seven of the eight responders (P = 0.028) compared with a non-significant fall in 3/7 of the non-respond er groups. The initial rate of superoxide production also fell in the responder group, but this was not statistically significant. Initial v alues in both the responder and non-responder groups were comparable w ith those seen for normal controls. Analysis of drug levels showed all patients to be compliant with drug treatment; however, drug levels an d neutrophil activity were not correlated. Studies of the effect of SA SP and sulphapyridine on superoxide production in vitro showed no diff erence between good and poor responders. These results suggest that th ere is no inherent difference between good and poor responders regardi ng the susceptibility of their neutrophils to SASP. SASP's action on n eutrophils, therefore, appears not to be its main mechanism of disease -modifying activity in RA.