IgA antibodies to human immunodeficiency virus in serum, saliva and urine for early diagnosis of human immunodeficiency virus infection in Ugandan infants

The value of HIV-1 IgA antibodies for early diagnosis of HIV infection in infants in serum, saliva and urine was investigated at Mulago Hospital, Kampala. Sensitivity and specificity in serum of HIV-infected infants at different ages were: 0 to1 months, 88 and 95%; 1 to 3 months, 88 and 97%; 4 to 6 months, 80 and 96%. They decreased between 67 and 77% and 80 to 91%, respectively, in older age groups. Sensitivity for saliva was lower (53 to 79%) and urine only 37 to 62%, although specificity was reasonably high (>85%). The high proportion of infants with raised HIV IgA in the first months of life (88%) may represent prenatal infection. Sensitivity of serum and especially salivary and urinary HIV IgA is too low to be of practical value for early diagnosis of HIV infection in infants.