Frequency of positive purified protein derivative test in those infected with human immunodeficiency virus

The objective of this study was to determine the frequency of positive purified protein derivative (PPD) skin test in those infected with human immunodeficiency virus (HIV) and to investigate its association with CD4-positive T cell count, demographic factors, and possible routes of transmission in Iran.

Fifty-one (36 males and 15 females) patients from an HIV clinic were selected and tested by a 5-tuberculin unit PPD.

The mean +/- SD age of patients was 32.2 +/- 7.9 years. The probable route of HIV transmission was intravenous drug using in 21 (41%, CI95%: 28 - 54%) and sexual transmission in 17 (33%, CI95%: 20 - 46%) patients. Thirteen (26%, CI95%: 14 - 38%) patients had other risk factors. There were 13 (25%; 10 males and 3 females) PPD-positive patients among HIV-infected patients when a cut-off value of 5 mm was used; there were 15 (29%; 11 males and 4 females) when a cut-off point of 2 mm was employed. In addition, there was no significant correlation between the PPD test using both cut-off values of 5 and 2 mm, and none of the three probable routes of HIV transmission including intravenous drug using, sexual, and others. The mean +/- SD CD4+ T cell count was 674 +/- 487/mm3 in men and 573 +/- 327/mm3 in women (P > 0.05). No significant correlation could be demonstrated between the patient's PPD positivity rate and CD4+ T cell count.

Considering the high rate of tuberculin reactivity, more attention should be paid to the importance of PPD test and isoniazid preventive therapy against tuberculosis in HIV-infected patients.