CD3+, CD56+ non-MHC restricted cytotoxic T lymphocytes in two fraternal AIDS patients: a case report

We describe two brothers with hemophilia and AIDS, with an unusually large percentage of CD3+, CD56+ lymphocytes. They experienced no major complications with opportunistic infections (OI) and infrequent secondary infections, even though they had nearly 0% CD4 lymphocytes for 3 years. Both patients died in 1991 of progressive cardiomyopathy. The patients' lymphocytes were immunophenotyped by flow cytometry and analyzed for functional cytolytic activity against K562 and HIV infected HUT 78 cell lines. Single color CD4 counts were 2-9% for 4 years. Dual color CD4 counts at our laboratory demonstrated 0-1% CD4 for the last 6 months. When CD3+ lymphocytes were examined, both patient 1 and patient 2 demonstrated a significantly higher proportion and absolute number of CD3"bright"+, CD56+ double-positive cells, 47% and 22%, respectively, compared to other HIV-positive children with hemophilia (< or = 2%). Functional studies with the K562 target cell line demonstrated the highest natural killer (NK) lymphocyte activity in patient 1 that could not be augmented by in vitro addition of IL-2, whereas patient 2 had no NK activity unless IL-2 was added. Functional studies with HIV-infected HUT-78 cells demonstrated patient 2 had cytolytic activity against HIV-infected cells and patient 1 had high nonspecific cytolytic activity even against uninfected HUT-78 cells, whereas controls had minimal activity to HUT-78 cells or HIV-infected HUT-78 cells. The case report raises a speculative question requiring a larger database, whether the anti-HIV activity and/or unusual clinical course without typical O.I. of some AIDS patients may be related to the presence of CD3"bright"+, CD56+ lymphocytes of their immune system.