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Expression of B7‐1 costimulatory molecules in patients with multibacillary leprosy and reactional states
Author(s) -
Santos D. O.,
Castro H. C.,
Bourguig S. C.,
Bastos O. M.,
Rodrigues C. R.,
Van Heuverswyn H.,
Nery J. A.,
Miranda A.
Publication year - 2007
Publication title -
clinical and experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 78
eISSN - 1365-2230
pISSN - 0307-6938
DOI - 10.1111/j.1365-2230.2006.02291.x
Subject(s) - flow cytometry , peripheral blood mononuclear cell , cd14 , immune system , mycobacterium leprae , immunology , antigen , lepromatous leprosy , immunohistochemistry , antibody , leprosy , medicine , biology , pathology , in vitro , biochemistry
Summary Background. The expression of B7 as a costimulatory molecule on the surface of antigen‐presenting cells such as macrophages and on dendritic cells characterizes the efficiency of the cell‐mediated immune response. Aims. Our purpose was to evaluate B7‐1 expression in peripheral blood mononuclear cells (PBMCs) immediately after cell isolation (‘spontaneous’ B7 expression), and in inflammatory cells from cutaneous lesions of patients with multibacillary leprosy (MB‐L) without and during the reactional states of erythema nodosum leprosum (ENL) or reversal reaction (RR). Methods. Peripheral blood samples and skin biopsies of eight patients without (MB‐L) and with reactional episodes (ENL and RR) were studied using antibodies against B7‐1, CD1b, DR and CD14 in flow‐cytometry and immunohistochemistry experiments. Results. The flow‐cytometry studies (mean ± SD% of fluorescent cells) revealed significant B7‐1 expression on PBMCs isolated from patients with ENL (8.0 ± 0.6%) and RR (15.0 ± 1.4%) compared with that observed for patients with MB‐L (0.4 ± 0.2%). Similar results were observed for cutaneous lesions of these patients by immunohistochemical assays. One patient studied before and during ENL revealed weak B7 expression before the reactional episode (0.3% of cells) compared with the marked level of B7‐expressing cells detected during ENL (8.5% fluorescent cells). Interestingly, an even higher B7 expression (15% of cells) was observed in patients with RR. Conclusions. Our results strongly suggest that B7 expression precedes reactional episodes in MB‐L, which could be related to the acquisition of effective immunity to Mycobacterium leprae during reactional episodes in leprosy. We propose B7 expression as a marker of CMI response in reactional episodes in leprosy.