Co-Trimoxazole in Wegener's Granulomatosis

To the Editor: In their study of treatment with co-trimoxazole (trimethoprim–sulfamethoxazole) to prevent relapses of Wegener's granulomatosis (July 4 issue), 1 Stegeman et al. do not report the cumulative doses of cyclophosphamide and prednisolone in their two groups of patients during the study period. Although this omission does not undermine their conclusion, it is relevant because the information may shed light on the mechanism by which co-trimoxazole prevents relapses. If, as Stegeman et al. speculate, co-trimoxazole either prevents infections that would have triggered relapses or has a direct antiinflammatory effect, then one would expect a lower cumulative dose of immunosuppressive agents . . .