Alterations in the concentrations and binding properties of sex steroid binding protein and corticosteroid-binding globulin in HIV+patients

The abnormal concentrations of steroid hormones and free fatty acids in the plasma of HIV-infected subjects are associated with qualitative and quantitative alterations in two of the major steroid hormones carrier proteins, sex steroid-binding protein (SBP) and corticosteroid-binding globulin (CBG). The properties of SBP and CBG in the sera of two age-matched groups of 67 men healthy blood donors (controls) and 64 HIV+subjects: 11 CDC group II and III (ASY), 6 CDC group IVA and 47 groups IV C1+D (AIDS) were analyzed. The HIV+patients had SBP concentrations 39-51% above those of controls. The sera of AIDS patients had higher SBP association constants (Ka) for testosterone than did those of the II, III and IVA groups and controls. In contrast, the CBG concentrations in all the HIV+subjects were similar to those of the controls. However, the binding properties of HIV+CBG were abnormal: the Ka's for cortisol and 17 alpha hydroxyprogesterone binding were 50% below normal, while the number of binding sites was significantly higher. Such changes in these carrier proteins could result from conformational transitions; they may cause abnormal transfer of hormonal information and/or steroid hormones metabolism, thus modifying the impact of steroids on the immune response in HIV+subjects.