Relapses in Wegener's granulomatosis: the role of infection.

Out of 20 relapses that occurred in patients with Wegener's granulomatosis, nine were provoked by bacterial or viral infection. Seven of these occurred during maintenance treatment in response to infection with common pathogens, and treatment of the infection alone was insufficient to produce remission. Circulating immune complexes were seen only in relapses due to infection and rarely in infections that occurred without relapse. A possible mechanism for infection-provoked relapses is that infection-derived complexes reactivate disease; alternatively, the acute-phase or cellular response to infection may enhance quiescent disease. Infection may exacerbate Wegener's granulomatosis and other autoallergic diseases, but whether it does so by a common mechanism is not known and further study is required.