Immunohistochemical localization of mycobacterium tuberculosis complex antigen with antibody to 38 kDa antigen versus Ziehl Neelsen staining in tissue granulomas of extrapulmonary tuberculosis.
BACKGROUND
Extra-pulmonary tuberculosis often presents a diagnostic challenge because of its diverse clinical manifestations and low yield of acid fast bacilli in tissue sections.


OBJECTIVE
The aim of the present study is immuno-histochemical localization of tuberculous bacilli or their components that persist in the granulomas but have lost the property of staining with acid fast stains and to assess the advantage of immuno-staining over conventional Ziehl Neelsen staining.


METHODS
Immuno-histochemical staining using species-specific monoclonal anti-body to 38 kDa protein of Mycobacterium tuberculosis complex and Ziehl-Neelsen staining for acid fast bacilli (AFB) was done on 69; 36 cases of confirmed extra-pulmonary tuberculosis and 33 non-tuberculous cases, in archival formalin fixed paraffin embedded tissue sections OBERVATIONS: AFB positivity was observed in only 36.1% of tuberculous granulomas while immuno-histochemical staining was positive in 100% of tuberculous granulomata with zero false positivity and negativity.


CONCLUSIONS
The immuno-hiostochemical localization of tuberculous bacilli and their components in tissue sections may be an efficient diagnostic adjunct to conventional ZN staining for the diagnosis of granulomas of extra-pulmonary tuberculosis. The technique is simple, sensitive and specific. It can be standardized and performed by trained technicians in routine laboratory. This will also help in clinical decision-making and in reducing the usual practice of prescribing empirical anti-tubercular treatment based on clinical suspicion alone in the absence of demonstrable evidence of tuberculous infection.
Goel
Madhu Mati
MM
Department of Pathology, King George's Medical University, Lucknow, U.P. madhukgmc@rediffmail.com
Budhwar
Puja
P
D000907:Antibodies, Bacterial / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000032:analysis*; D000942:Antigens, Bacterial / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D003937:Diagnosis, Differential; D005260:Female; D006099:Granuloma / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000302:isolation & purification; D013194:Staining and Labeling / Q000379:methods*; D014376:Tuberculosis / Q000382:microbiology* / Q000473:pathology
D000907:Antibodies, Bacterial; D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial; D001324:Autoantigens; C089731:islet 37k antigen