title: Tuberculin skin-test reactions are unaffected by the severity of hyperendemic intestinal helminth infections and co-infections.
abstract: 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 (> or = 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.
authors.affiliation: Department of Microbiology, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Karine
authors.initials: K
authors.lastname: Zevallos
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Vergara
authors.forename: Antonio
authors.initials: A
authors.lastname: Vergara
authors.forename: Carlos
authors.initials: C
authors.lastname: Vidal
authors.forename: Hector H
authors.initials: HH
authors.lastname: Garcia
authors.forename: Carlton A
authors.initials: CA
authors.lastname: Evans
mesh_terms: D000328:Adult; D015766:Albendazole / Q000627:therapeutic use*; D000871:Anthelmintics / Q000627:therapeutic use*; D004311:Double-Blind Method; D019353:Endemic Diseases; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007411:Intestinal Diseases, Parasitic / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis*
chemical_list: D000871:Anthelmintics; D015766:Albendazole