The question of how effective the repopulation of CD4 lymphocytes is in the prevention of reactivation of opportunistic infections in patients with advanced AIDS who have been placed on highly active antiretroviral therapy (HAART) was addressed by a report from the University of California at San Francisco. Mark Jacobson, a leading researcher from this institution reported on 5 cases of AIDS patients with CMV retinitis who had CD4 counts over 200 cells/mm3 at the time of diagnosis. Previous natural history studies have shown that CMV retinitis occurs almost exclusively in patients with CD4 counts < 50 cells/mm3. Up to two months prior to the CMV diagnosis all the patients had initiated HAART, mostly protease inhibitor containing combination therapies.
In another analysis of 76 consecutive patients enrolled in a prospective treatment trial for patients with newly diagnosed CMV retinitis from March 1996 to August 1996 a larger percentage of patients had CD4 counts > 50 cells/mm3 at the time of the CMV diagnosis than similar patients enrolled from July 1995 to February 1996, prior to the general availability of HAART. These findings suggests that the immunological benefits of HAART may not fully protect against CMV retinitis which may now occur more commonly in patients with CD4 counts > 50 cells/mm3.
Another report from France also noted the onset of acute CMV infections among 8 patients with low CD4 counts (mean = 37) who were started on combination therapy including protease inhibitors. Acute CMV infection (retinitis, submaxillitis, pseudotumoral colitis, pneumonitis, CMV viremia) occurred despite clinical improvement of the patients and an increase by more than 5 fold in mean CD4 counts. The average time from the first administration of protease inhibitors and the onset of the CMV event was 37 days. In contrast most other studies presented at the conference noted declines in the incidence of other major opportunistic infections, and even resolution of some without specific antiinfective and antitumor therapy, including chronic cryptosporidiosis, progressive multifocal leukoen- cephalopathy and Kaposi's sarcoma, wasting syndrome and Parvo virus infections. One study however reported that HAART could unmask subclinical Mycobacterium avium complex infections localized to lymph nodes or skin by way of enhanced immune responses.