FALLING CD4 COUNTS IN HIV-INFECTION - RELATIONSHIP TO THYROID-HORMONE AND THYROID-HORMONE BINDING GLOBULIN (TBG) - A REVIEW AND NEW FINDINGS

CD4 counts are routinely used to mark the progression from asymptomatic human immunodeficiency virus (HIV) infection to AIDS. Tests of thyroid function have been reported to be higher, lower, and unchanged from normal during this progression. In this study, we examinined HIV-infected individuals and compared these laboratory parameters to general measures of health status such as body mass index and age. Using CD4 counts as a marker, we found that thyroid function tests are normal even in patients with very low CD4 levels. Thyroid binding globulin, by contrast, rises as CD4 counts fall. Liver disease confounds the correlation of low CD4 and high thyroxine-binding globulin (TBG), which is still present, albeit more weakly. In summary, the practicing endocrinologist should look for a primary thyroid disorder in HIV positive patients with abnormal thyroid tests, but view an elevated TBG as another sign of HIV disease progression.