Vasculatures in the extranodal B cell lymphoma.

11 cases received operation for primary B cell lymphoma of the gastrointestinal tract were studied immunohistochemically to clarify vascular endothelial cell (EnC) function in extranodal lymphoma tissues. Microvasculature in primary B cell lymphoma of the gastrointestinal tract, based on the morphological characteristics, were devided into high endothelial cell vessels (HEV) and flat endothelial cell vessels (FEV). HEV were characterized as HLA-DR- OKM1- OKM5- F VIII RAg+ IL-1-, accompanied by the cluster of non-neoplastic T lymphocytes, and FEV were HLA-DR- OKM1- OKM5+ F VIII RAg+ IL-1- not by T lymphocyte infiltration. In contrast, microvascular EnC in the surrounding non-lymphoma tissue, normal gastric and ileal tissues showed HLA-DR+ IL-1+. Our results suggest that microvascular EnC in primary B cell lymphoma of the gastrointestinal tract lack a fuction as antigen presentation, and that HEV regulate non-neoplastic T cell migration.