Loss of cytomegalovirus-specific CD4 T cell responses in human immunodeficiency virus type-1-infected patients with high CD4 T cell counts and recurrent retinitis [Komanduri KV, et al. JID 2001;183:1285]: The authors report two patients who had CD4 cell responses to over 400/mm³ with HAART and a history of CMV retinitis. One patient had CMV retinitis with a nadir CD4 cell count of 225/mm³, developed CMV retinitis, responded to HAART, but relapsed with an attempt to withdraw foscarnet when his CD4 cell count was 989/mm3. The second patient had a CD4 nadir of 12/mm³, developed CMV retinitis which responded to foscarnet, received HAART, and had four recurrences with attempted withdrawal of CMV therapy when the CD4 cell count was 400-700/mm³. Both patients had laboratory-demonstrated defects in CMV-specific CD4 T cell responses as the presumed explanation.
Comment: The ability to suspend secondary prophylaxis for virtually all OIs has been convincingly demonstrated for PCP, disseminated MAC, toxoplasmosis, CMV retinitis and, to a lesser extent, cryptococcal meningitis. There are, however, a few exceptions. There are now about six case reports of CMV retinitis relapse when treatment was discontinued due to immune reconstitution. This report accounts for two of these and was reported at the 7th CROI meeting in San Francisco (Abstract B51e). A particularly strong feature of the present report is the presumed explanation ascribed to a deficit in CMV-specific CD4 T cell responses. By contrast, the authors reported a control group of 14 patients who successfully discontinued treatment for CMV retinitis showed and good CMV-specific responses. Both patients with recurrent retinitis in this report had multiple relapses indicating that, despite a robust CD4 cell response, there was not only the lack of a baseline response, but failure to generate this response with repeated antigenic stimulation. The authors describe this as a "hole" in the immunologic repertoire.
posted 4/25/2001

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