Capacity to produce interleukin 2 is impaired in haemophilia in the absence and presence of HIV 1 infection.

Capacity to produce interleukin-2 (IL-2) was measured in haemophiliacs from a well-defined treated cohort. Patients were selected on the basis of HIV-1 antibody status, mean annual dose of clotting factor and liver disease severity. T-cell subsets and peripheral blood mononuclear cell proliferation to Mycobacterium tuberculosis purified protein derivative (PPD) were also measured. Haemophiliacs had reduced IL-2 production, independent of HIV-1 antibody status, mean annual dose of clotting factor concentrate used and liver disease severity. In HIV-1 antibody positive patients reduced levels correlated with PPD proliferative responses (r = 0.6, P = 0.04) and CD8 + ve (r = 0.5, P = 0.05) but not CD4 + ve cell numbers (r = 0.3, P = 0.2). No such correlations were seen in HIV-1 antibody negative patients. Reduced IL-2 production in HIV-1 antibody negative haemophiliacs was due to a qualitative defect. In HIV-1 positive patients a qualitative defect in T lymphocytes that selectively proliferate in response to PPD was observed. CD4 + ve cell numbers were reduced in HIV-1 positive patients.