HIV antibody responses in children of HIV-infected mothers

About 25% of the children of untreated HIV-infected mothers are later determined to be HIV-infected. At birth, all of the children of HIV-infected mothers have HIV-IgG antibody, which is transferred transplacentally from the mothers to their children, and infected children produce HIV-IgG antibody in response to their infection. Most infected children have detectable HIV-IgA by 3 months of age. We have studied HIV antibody responses in three groups of children of HIV-infected mothers at 9 to 12 months and 15 to 24 months of age. The groups were classified by Centers for Disease Control and Prevention (CDC) criteria and included: (I) HIV seroreverters (SR); (II) HIV-infected; Non- to mildly symptomatic (N+A); and (III) HIV-infected; Moderately to Severely Symptomatic (B+C). HIV-IgG antibody was detected in some SR children at low titer levels (10 to 20) through 11 months of age but not at 12 or later. For both the N+A and B+C groups, there were no significant changes in the mean HIV-IgG titers from 9-12 to 15-24 months of age. Also, no significant difference in titers were found between the two infected groups for both age groups. HIV-IgA antibody responses were more frequently positive at 15 to 24 months for all seven antigens studied for the N+A than the B+C patients; however, statistical significance was attained only for gp41 (p < or = 0.01). N+A children showed more responses to the viral antigens at 15-24 months than at 9-12 months. This increase in HIV-specific IgA among the N+A children may be important in restricting their HIV infections. Total IgG levels were significantly higher in the HIV-infected groups than in the SR (p < or = 0.0001), but no differences were detected between the N+A and B+C groups. Total IgA increased over time in the N+A patients from 9-12 to 15-24 months. A similar trend was apparent in the B+C group, but did not reach statistical significance. Both N+A and B+C patients at 15-24 months had significantly higher total IgA levels than did the SR at 9-12 months of age. The B+C group had significantly lower CD4 counts for both age groups than did the N+A or SR groups (p < or = 0.0001).