Ihab Hamed Nourein, Hussain Gadelkarim Ahmed, Hassan Elsiddig Hassan, Mohammed Ayed Huneif, Abdelrahman Mohamed Abdelrahman, Abuobieda Balla Abusharib
Abstract: Background: The clinical and histological criteria used to diagnose lymphadenitis caused by MTB organisms have low sensitivity, and poor specificity. We report a novel method for diagnosis of pediatric tuberculosis that uses Monoclonal anti 38-KD immunohistochemistry (IHC) to detect the 38- KD antigen on formalin-fixed tissue biopsies. This antigen has not been detected in non- tuberculous mycobacteria. Polymerase chain reaction (PCR) for amplification of IS6110 from DNA obtained from the biopsies was used as a gold standard in this Study. Methodology: Of 718 lymphadenopathy cases, 42 pediatric cases of granulomatous lymphadenitis with histologically suspected tuberculosis obtained from Sudan were evaluated. Z.N stain, IHC and PCR techniques were used for diagnosis. Positive and negative control for IHC and PCR were used to standardize the assays. Result: Z.N stain, IHC, and PCR positivity were observed in 1/42 (2.4 %), 33/42 (78.6 %), and 33/42 (78.6 %) of granulomatous lymphadenitis cases respectively. Z.N stain had sensitivity, specificity, sensitivity, specificity, PPV and NPV of 2.9 %, 100 %, 100 %, and 55 % respectively, while IHC had sensitivity, specificity, PPV and NPV of 100 %, 100 %, 100 %, and 100 %, respectively. Conclusion: IHC with anti-38-KD antiserum is a rapid, sensitive, and specific method for establishing an etiological diagnosis of Pediatric tuberculosis in histologic specimens. It can be standardized and performed by trained technicians in routine laboratory.
Keywords: Tuberculosis, Pediatric, Immunohistochemistry, Sudan