Relationship between herpes simplex virus ulceration and CD4+ cell counts in patients with HIV infection

Objective: To establish the incidence of herpes simplex virus (HSV) ulceration in relation to CD4+ cell counts in HIV-infected patients. Design: Swabs were taken from all ulcerated lesions in HIV-infected patients and cultured for HSV. CD4+ cell counts were performed at regular intervals. Setting: The HIV unit at a London teaching hospital (the Royal Free Hospital, London, UK). Patients: All HIV-infected patients (n = 500) attending the HIV unit. Results: Two hundred and twenty-three swabs were obtained from 118 patients; 83 (37.2%) swabs from 62 (52.5%) patients were positive for HSV. Of 96 swabs taken from patients with CD4+ cell counts < 50 x 10⁶/l, 56 (58.3%) were positive for HSV, compared with 27 of 127 (21.2%) swabs from patients with higher CD4+ cell counts (P < 0.0001). Of patients with CD4+ cell counts < 50 x 10⁶/l, 37 of 47 (78.7%) had positive cultures compared with 25 of 71 (35.2%) of patients with higher counts (P < 0.0001). This trend was observed with swabs from all body sites; sufficient samples were available from oral and perianal lesions to demonstrate statistical significance (P < 0.0001 and P = 0.007, respectively). Conclusions: These results show a sharp rise in the incidence of HSV with CD4+ cell counts < 50 x 10⁶/l and thus provide important data for the design of studies of anti-HSV prophylaxis. Furthermore, since nearly 60% of all ulcers in patients with such low CD4+ counts are HSV-positive, we suggest appropriate empirical therapy on presentation.