Defining the population of human immunodeficiency virus-infected children at risk for Mycobacterium avium-intracellulare infection.

We reviewed the 22 cases of Mycobacterium avium-intracellulare (MAI) infection that occurred among 196 human immunodeficiency virus-infected children seen at the National Cancer Institute Pediatric Branch from December 1986 through April 1991, and an additional 65 charts from children with cultures negative for MAI. All patients with proven MAI were receiving antiretroviral therapy with zidovudine, dideoxyinosine, or a combination of zidovudine and dideoxycytidine. All patients had disseminated MAI infection, except one adolescent who had only evidence of localized lymphadenitis. All cases of MAI but one were diagnosed before death. The overall incidence of MAI was 11% in our patients but increased to 24% in patients whose absolute CD4 cell counts were < 100 cells/mm3. Symptoms most commonly associated with MAI infection included recurrent fever (86% of patients), weight loss or failure to thrive (64%), neutropenia (55%), night sweats (32%), and abdominal pain (27%). Children infected with MAI had a mean CD4 percentage of 2% (range, 0% to 7%) and a mean absolute CD4 count of 12 cells/mm3 (range, 0 to 48 cells/mm3), significantly lower than in the remainder of the clinic population or the group of children with cultures negative for MAI. Of 20 patients with MAI infection who were tested, 10 had measurable p24 antigen with a mean value 939 pg/ml (range, 77 to 3270 pg/ml) compared with 19 of 59 patients without MAI infection in whom the mean positive value was 413 pg/ml. There was no difference in survival time between those children with documented MAI infection (median survival time, 45.5 weeks) and those with similarly low CD4 counts and cultures negative for MAI (median survival time, 50.4 weeks). Future improvements in therapeutic options may make screening of pediatric human immunodeficiency virus-infected patients with low CD4 counts a reasonable plan.