"Thus, the bimodal pattern of progression in pediatric AIDS may largely be explained by differences in the potential of (certain) HIV strains (with particular affinity to the thymus and which can cross the placenta during gestation) to cause early thymic disruption... "In addition to their pathogenetic importance, our findings have clinical implications that include the need for prompt identification of patients in whom AIDS progresses early and who have the thymic-defect profile," the authors report.
High-risk infants may be identified currently by blood test measurements of the joint distribution of their CD4+ and CD8+ T cells counts, as well as by obtaining CD5+ B cell counts, as early after birth as possible. Newer tests being developed by the Emory group involving the virus may provide other, even earlier, methods of identification.
"The recent recommendations (made by the U.S. Centers for Disease Control and Prevention) for early prophylaxis against P. carinii pneumonia in all HIV-exposed children may prove particularly beneficial in children under the age of six months," the authors conclude. "Therapeutic approaches will need to be more aggressive among these infants, with earlier use of antiviral agents and perhaps even immune reconstitution with thymic transplantation (currently being explored by the Emory group)."
Other Emory authors of the study included Christian Ibegbu, Ph.D.; Francis K. Lee, Ph.D.; Mary K. Sawyer, M.D.; and Steven Nesheim, M.D., all of the Division of Infectious Diseases, Epidemiology and Immunology of Emory's Department of Pediatrics, and W. Scott Clark, Ph.D., of Emory's Rollins School of Public Health.