Purpura cerebri in Gram-negative septicaemia. A histological and immunohistochemical study

Abstract

Two cases with brain purpura following Gramnegative septicaemia were examined morphologically and immunohistochemically. The brain lesions, including ball and ring haemorrhages, a few days old, with some microglial cells accumulated around the older foci, were restricted to the white matter. Immunohistochemically, scanty deposits of IgG, IgA and IgM mainly in the macrophages in brain, kidneys and lungs were found, whereas staining with antibodies directed against IgE and complement (C3, C4) remained negative. In the brain, immunoglobulin deposits were located mainly in the macrophages, furthermore, in and around the walls of a few intact (non-haemorrhagic) vessels; within the perivascular haemorrhagic foci no deposits could be demonstrated. The relevance of these observations to the pathogenesis of brain purpura is discussed.