Interleukin 4 and gamma-interferon may play a role in the histopathogenesis of peripheral T-cell lymphoma.

The first demonstration of cytokine expression in T-cell lymphoma by immunohistochemical methods is reported. Lymph node biopsy specimens were obtained from 18 patients with peripheral T-cell lymphoma. Interleukin 4 (IL-4) and gamma-interferon were each detected in 7 lymph nodes. Lymph node specimens diagnosed as angioimmunoblastic T-cell lymphoma and angiocentric lymphoma having distinctive histopathological features expressed IL-4 more frequently than other T-cell lymphomas, and all 7 patients expressing IL-4 had hypergammaglobulinemia. Lymph nodes with gamma-interferon expression showed an increase in histiocytes and/or epithelioid cells. Thus, IL-4 may play an important role in the development of hypergammaglobulinemia as well as in the growth and histopathogenesis of T-cell lymphoma, and gamma-interferon may be responsible for the development of Lennert's lesion.