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Tuberculin Skin-Test Reactions Are Unaffected by the Severity of Hyperendemic Intestinal Helminth Infections and Co-Infections

2010; American Society of Tropical Medicine and Hygiene; Volume: 83; Issue: 2 Linguagem: Inglês

10.4269/ajtmh.2010.10-0073

1476-1645

Karine Zevallos, Katherine C. Vergara, Antonio Vergara, Carlos Vidal, Héctor H. García, Carlton A. Evans,

Diagnosis and treatment of tuberculosis

The tuberculin skin test (TST) quantifies cell-mediated immunity to tuberculosis antigens. Helminths suppress cell-mediated immunity, so we studied the effect of helminth infection and deworming on the TST in a randomized, double-blind, placebo-controlled study in an indigenous Amazon community ( N = 195). Stool microscopy diagnosed helminths in 98% and co-infection with multiple species in 24% of study subjects. The TST was positive (≥ 10 mm) for 49%, and responses increased with age ( P < 0.001), Bacille Calmette Guerin (BCG) vaccination ( P = 0.01), and tuberculosis contact ( P = 0.05). TST results had no association with helminth-egg concentrations, species, or co-infections (all P > 0.1). One month after deworming with albendazole (three daily 400-mg doses), helminths were reduced, but 63% remained infected with helminths. Albendazole did not cause a change in TST size ( P = 0.8) or positivity ( P = 0.9) relative to placebo. Thus, TST reactions were unaffected by albendazole therapy that partially cured intestinal helminth infections, and TST interpretation was unaffected by high-burden helminth infections and co-infection with multiple helminth species.