Generalized immune activation in pulmonary tuberculosis: Co-activation with HIV infection

Parameters of immune activation/differentiation were studied in a group of newly diagnosed HIV^- and HIV⁺ pulmonary tuberculosis (TB) patients. Compared with controls, HLA-DR expression on both CD4 and CD8 T cells from the HIV^- TB patients was approximately doubled; HLA-DR on T cells from the HIV⁺ group was tripled. The monocytes from both groups of patients expressed abnormally high levels of the Fcγ receptors I and III. Serum levels of tumour necrosis factor-alpha (TNF-α), neopterin and β₂-microglobulin were increased in HIV^- and even more so in HIV⁺ TB patients. The expression of HLA-DR on T cell subsets and of FcγR on monocytes correlated with each other, but not with serum activation markers. This pattern of non-specific activation during TB infection may be associated with enhanced susceptibility to HIV infection.