Analysis of apoptosis and Bcl-2 expression in polar forms of leprosy.
Apoptosis eliminates pathogen-infected cells. Its modulation can influence the course of infections, permitting the survival of intracellular pathogens. In leprosy, which presents several clinical manifestations related to bacillary burden and host immune status, the mechanisms responsible for the persistence of the bacillus are unknown. Few studies have focused on apoptosis over the disease spectrum and as a defense mechanism against Mycobacterium leprae. We evaluated apoptosis using terminal transferase dUTP nick end labeling and the expression of Bcl-2 by immunohistochemistry in skin lesions from 11 tuberculoid and 15 lepromatous leprosy patients. Each specimen was evaluated by determining the number of positive cells in 10 fields at × 400 magnification. We observed a higher number of apoptotic cells in tuberculoid lesions in comparison with lepromatous leprosy (42.5 cells per 10 fields vs. 11.5 cells per 10 fields, P<0.0001). Expression of Bcl-2, conversely, was larger in lepromatous than in tuberculoid samples (172.0 cells per 10 fields vs. 17.7 cells per 10 fields, P<0.0001). These observations suggest modulation of apoptosis in leprosy, primarily in lepromatous patients, for which the decrease in cell death could support M. leprae survival and contribute to the success of infection. Conversely, in tuberculoid patients, apoptosis could contribute to reducing propagation of the bacillus.
Equipe Técnica de Imunologia, Instituto Lauro de Souza Lima, Bauru, São Paulo, Brazil. vbrito@ilsl.br
Vânia Nieto
VN
Brito de Souza
Maria Esther Salles
ME
Nogueira
Andréa de Faria Fernandes
Ade F
Belone
Cleverson Teixeira
CT
Soares
D017209:Apoptosis; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D015440:Leprosy, Lepromatous / Q000473:pathology*; D015441:Leprosy, Tuberculoid / Q000473:pathology*; D009166:Mycobacterium leprae / Q000472:pathogenicity*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D012867:Skin / Q000473:pathology*
D019253:Proto-Oncogene Proteins c-bcl-2