The effect of tuberculin skin testing on viral load and anti-mycobacterial immune responses in HIV-1-infected Ugandan adults.

OBJECTIVE

To determine whether tuberculin skin testing (TST) is associated with an increase in human immunodeficiency virus (HIV) viral load, and to examine the effect of TST on anti-mycobacterial immune responses.

DESIGN

A nested cohort study of HIV-1-infected adults.

METHOD: Forty-two participants (21 TST-positive and 21 TST-negative) from a larger cohort were recruited to the study. Blood was collected for CD4+ T-cell count, whole blood was cultured, and plasma saved for viral load. These measurements were taken before, 3 days after, 3 months after, and 3 months plus 3 days after TST. Cytokine responses to culture filtrate proteins (CFP) of Mycobacterium tuberculosis and phytohaemagglutinin (PHA) were examined in the whole blood assay.

RESULTS

Twenty-nine participants attended all four visits. No statistically significant change in viral load, CD4+ T-cell count, or cytokine response to PHA was observed at any visit. However, TST was associated with a transient increase in the interferon-gamma response to CFP and a lasting increase in the interleukin-5 response to CFP.

CONCLUSION

There appeared to be a systemic effect of TST on the anti-tuberculosis immune response.