Paper # 096

Thymic microenvironmental changes in human congenital syphilis

Eliene C. Fonseca, Mônica P. Almeida, Évlin H. Maia, Dora M. F. Menezes and Wilson Savino*
Departament of Pathology, Fluminense Federal University, Niterói, Brazil.

Address: Rua Marquês do Paraná, 303
Niterói - RJ - Brazil - CEP:24.030-210

[Introduction] [Materials and Methods] [Results] [Discussion] [Pictures] [Bibliography]

Summary

We investigated fourteen human thymus obtained from necropsies of stillborns and neonates dying of congenital syphilis by histological and immunohistochemical methods for extracellular matrix components (types I, III and IV collagens, fibronectin and laminin), thymic epithelial (TEC) networks and B cells. Important changes on thymic ECM and epithelial network alterations beside thymocyte depletion were observed. We found an uncommon pattern of abnormal intra-thymic ECM distribution and anti-ECM B cell autorreactivity, evidenced by circulanting anti-ECM antibodies as well as intrathymic immunoglobulin bound to basement membrane . Thymic tissues severely affected by fibrosis showed an increased cortical B cells population, plasmocytes and hematopoietic precursor widespread in septal areas.

Our findings together with others experimental and human diseases suggest that intrathymic events, particularly thymocyte death, can be abnormally modulated by these microenvironmental changes.

References :

Savino W.: The thymic microenvironment in infectious diseases. Mem. Inst. Oswaldo Cruz 85: 255, 1990.

Savino W., Leite de Morais M.C., Silva Barbosa S.D., Fonseca E.C., Cotta-de-Almeida V. & Hontebeyrie-Joscowics M.: Is the thymus a taget organ in infectious diseases? Mem. Inst. Oswaldo Cruz, 87(suppl.5) : 73, 1992.

Savino W., Villa-Verde D.M. & Lannes-Vieira J.: Extracellular matrix proteins in intrathymic T-cell migration and differentiation. Immunol. Today 14(4): 158, 1993

Dra. Eliene C. Fonseca is immunopathology professor at Fluminense Federal University and works with immunohistochemistry, in situ hybridization, congenital infections and thymus. Dr. Wilson Savino is head of hymic research laboratory of the Immunology Department at Fiocruz, RJ.

Antônio Pedro Universitary Hospital is a public hospital situated in Niterói, the 4 th. city in life quality in Brazil. It has more than a million habitants an is less than 15 Km away from the city of Rio de Janeiro.

Key Words: Thymus, Congenital syphilis, Extracellular matrix.