HIV-infected subjects have an increased frequency of T cells that stain for the cytolytic granule protease grnA. (A) CB9 MoAb stains about 25% of the circulating lymphocytes of a healthy donor but stains the majority of circulating lymphocytes in HIV-infected subjects. (B) An increased number of circulating CD4 (□), CD3 (▪), and CD8 (⊡) T cells in HIV-infected subjects (graphed for representative subjects in order of increasing immunodeficiency) contain the cytolytic effector molecule, grnA. CD16⁺(▧) NK cells from healthy and HIV-infected donors uniformly contain grnA.