Relationship Between CD4 Lymphocyte levels and PPD skin test Measurement in Adult Aids Patients with pulmonary tuberculosis

Abstract

A simple and inexpensive procedure lilke the purified protein derivative (PPD) skin test may be alternative marker of disease progression in human immunodeficiency virus (HIV) infected individuals. The correlation between the PPD induced skin induration and the CD4 T lymphocyte levels (absolute CD4 counts and percentages was evaluated in acquired immunodeficiency syndrome (AIDS) patients with pulmonary tuberculosis. This pilot study was carried out at the Chonburi General hospital and the zonal tuberculosis (TB) center in Chonburi, thailand. A total of 22 AIDS patients with pulmonary tuberculosis and 20 HIV seronegative pulmonary tuberculosis patients with (controls) were skin tested with 5 tuberculin unit (TU) of PPD. Anergy was observed in 82% of AIDS cases, all with very low CD4 counts. Teh remaining 18% showed skin reactions ranging between 1mm and 9mm. The parsons correlation coefficient test showed a good correlation between the PPD induration measurement and the absolute CD4 counts. Teh coefficient r = 0.79 (p< 0.001) with the absolute CD4 counts, and  r = 0.60 (p<0.001) with the percentage of CD4 lymphocytes. In the control group, no such correlation was found and anergy was not observed in any of the patients. With a larger smaple size, the association may be better established and may predict the level of CD4 T lymphocytes and hence disease progression, especially in areas of high case load of AIDS and Tuberculosis.