High Expression Apoptotic Proteins; P53, FAS, and BAX Associated with Down Regulation BCL-2 in Tuberculosis Granulomas: An Immunohistochemistry Study

Apoptosis can be stimulated or inhibited by different signals or cell-cycle arrest proteins, each plays a specific role during Mycobacterial infection. This study analyses the expression and co-relation of apoptotic and anti- apoptotic proteins (P53, FAS, BAX and BCL-2) in human Tuberculosis granulomatous tissue reactions by immunohistochemistry. The formalin fixed paraffin embedded blocks of different biopsy specimens from 40 documented TB patients were studied by immunohistochemical staining for expression of P53, FAS, BAX and BCL-2 proteins; 28, 26, 12, 32 paraffin blocks, respectively. In epithelioid macrophages of TB granulomas, high positivity for P53 (100%), BAX (83.3%), and FAS (57.7%) was associated with down regulation of BCL-2 (12.5%). Although, the reaction of surrounding small lymphocytes was vice versa. The multinucleated giant cells also revealed positive reaction for P53 (92.8%) and BAX (83.3%) proteins. In comparison to previous findings, our studies revealed immunolocalization of P53, FAS, and BAX in MTB granulomas by a simple routine pathological method. These findings also re-emphasize the value of immunohistochemical studies in regard to the role of apoptotic proteins in MTB infection pathogenesis. These studies may lead to further effective and better therapeutic strategies in TB patients.(Tanaffos 2005; 4(13): 11-19)