Immune Reconstitution to Measles Virus of HIV-1-Infected Zambian Children Initiating Antiretroviral Therapy

This is a prospective, observational cohort study of 230 HIV-1-infected children initiating ART at public clinics in Lusaka, Zambia to measure the magnitude and quality of general immune reconstitution and pathogen-specific immune reconstitution to measles virus. Non-specific immune reconstitution will be assessed by serial measurements of the number and percentages of CD4+ and CD8+ T-lymphocytes, number and percentages of activated CD4+ and CD8+ T-lymphocytes (using cell surface staining for HLA-DR and CD38), changes in the proportions of naïve and memory CD4+ and CD8+ T-lymphocyte subsets (using cell surface staining for CD45RA and CCR7), and changes in thymic output as determined by TREC levels. Virologic responses to ART will be assessed by serial measurements of plasma HIV-1 RNA levels.

Within the observational study, there is a nested study of revaccination against measles virus of HIV-1-infected children receiving ART who lack protective antibody titers to assess the proportion of revaccinated children who develop protective immunity and the duration of protective immunity. Anti-measles virus IgG antibodies will be measured 9 months after initiation of ART. The results will be available at the 12-month follow-up visit and measles revaccination will be recommended to those children lacking protective antibody levels to measles virus.