[Familial hemophagocytic lymphohistiocytosis]

7 cases of familial hemophagocytic lymphohistiocytosis were investigated by morphology and immunohistochemistry. Typical infiltrates composed of macrophages and lymphoid cells were found in various locations such as lymph nodes, spleen, liver, brain, and skin. The macrophages were positive for typical macrophage antibodies (Ki-M1, Ki-M1P) and showed features of activation by displaying a strong reaction with antibodies against lysosomal antigens (Ki-M1P, Ki-M6, Ki-M7, Ki-M8). In addition, they showed antigenic similarity to antigen-presenting cells (Vit-6 pos., S 100 pos.) and no conclusive evidence of in situ proliferation (Ki-67 neg). The lymphoid cells were mainly composed of more or less proliferating T-cells and a few B-cells.