We determined the incidence of herpes zoster (HZ) in 119 patients with systemic lupus erythematosus (SLE). HZ occurred in 56 patients (47%), and 9 patients had had HZ even before SLE developed. After diagnosis of SLE, an incidence of zoster was high, 5.45 cases per 100 person-years.
It was found that the susceptibility to HZ was not related to the presence of renal disorder or maximum dose of corticosteroids. The patients with SLE who had had HZ showed significantly higher antibody titers than those without a history of HZ and normal subjects as assayed by both complement fixation technique and neutralization test. On the other had, only 17 of 55 patients (31%) with SLE showed positive skin reactions to varicella zoster virus (VZV) antigen, whereas all 15 normal subjects had positive reactions. In the patients who were receiving less than 10 mg/day of prednisolone, 11 of 17 (65%) had positive skin reactions to VZV antigen, whereas only 4 of 31 (13%) patients who were receiving 10 mg/day or more prednisolone showed positive reactions. It was of interest that in 7 patients with SLE who had not received corticosteroids, only 2 (29%) patients showed positive skin reactions to VZV antigen.
These results suggest that high incidence of HZ in patients with SLE is probably due to an impaired cellular immunity because of both underlying disease and corticosteroid treatment.