Shirin Sayyahfar1, Abdollah Karimi2, Alireza Fahimzad2, Ahmad Reza Shamshiri3. 1. Division of Pediatric Infectious Diseases, Department of Pediatrics, Ali Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran. Electronic address: sayyahfar.sh@iums.ac.ir. 2. Division of Pediatric Infectious Diseases, Pediatric Infectious Research Center(PIRC), Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 3. Dentistry Research Institute, Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Abstract
BACKGROUND: The aim of this study is to compare Tuberculin Skin Test (TST) result and interferon gamma response to human PPD (purified protein derivative), in scar positive and scar negative BCG-vaccinated children. METHODS: Between August 2007 and May 2008 a total of 236 children aged 1-168 months (mean 21 months) admitted to Mofid Children's Hospital, Tehran, Iran, were enrolled in a cross-sectional study. Each patient was examined for BCG vaccine scar and tested with TST and human PPD-based Interferon Gamma Release Assay (IGRA). RESULTS: Two hundred and twenty one cases out of 236 (44% female, 1-168 months, mean age 21 months) were scar positive of whom 95% TST result was negative. Human PPD-based IGRA was positive in 110 (49.8%), negative in 85 (38.4 %) and indeterminate in 26 (11.8%) of scar positive patients. Fifteen children (40% female, 1-156 months; mean age 42 months) were scar negative. All the scar negative cases were TST negative. Human PPD-based IGRA was positive in 10 (66.7%), negative in 4 (26.7%) and indeterminate in 1 (6.7%) of scar negative patients. CONCLUSIONS: Immune responsiveness to human PPD antigens in scar positive and negative children may not correspond with results of the Tuberculin Skin Test.
BACKGROUND: The aim of this study is to compare Tuberculin Skin Test (TST) result and interferon gamma response to humanPPD (purified protein derivative), in scar positive and scar negative BCG-vaccinated children. METHODS: Between August 2007 and May 2008 a total of 236 children aged 1-168 months (mean 21 months) admitted to Mofid Children's Hospital, Tehran, Iran, were enrolled in a cross-sectional study. Each patient was examined for BCG vaccine scar and tested with TST and humanPPD-based Interferon Gamma Release Assay (IGRA). RESULTS: Two hundred and twenty one cases out of 236 (44% female, 1-168 months, mean age 21 months) were scar positive of whom 95% TST result was negative. HumanPPD-based IGRA was positive in 110 (49.8%), negative in 85 (38.4 %) and indeterminate in 26 (11.8%) of scar positive patients. Fifteen children (40% female, 1-156 months; mean age 42 months) were scar negative. All the scar negative cases were TST negative. HumanPPD-based IGRA was positive in 10 (66.7%), negative in 4 (26.7%) and indeterminate in 1 (6.7%) of scar negative patients. CONCLUSIONS: Immune responsiveness to humanPPD antigens in scar positive and negative children may not correspond with results of the Tuberculin Skin Test.