Immunological aspects of immunodeficiency diseases part 85

A number of genetic defects that affect the efficiency of T-cell- and NK-cell-mediated cytolysis can predispose to the development of HLH. Cytolysis by T cells and NK cells is initiated by the secretion of contents of cytolytic granules at the immunological synapse between the T cells and the target cells. The process involves the translocation of perforin-containing lytic granules onto the target cell interphase, followed by fusion of these granules with the plasma membran of the T cell, with release of perforin onto the surface of the target cell. Perforin punches holes in the target cell membrane, causing cytolysis.