Immunohistochemical identification of adult and fetal haemopoiesis in the spleen in lymphoma, leukaemia and myeloproliferative disease.

Antisera to adult and fetal haemoglobins were used in the immunoperoxidase method to identify haemopoietic cells in spleens from patients with lymphoproliferative and myeloproliferative disorders. Splenic extramedullary haemopoiesis in adults often contains a major fetal component. Spleens infiltrated by Hodgkin's lymphoma are invariably negative, but other lymphomas, leukaemias and myeloproliferative diseases are commonly associated with splenic fetal haemopoiesis. Immunoperoxidase staining for haemoglobins is a useful way of determining the haemopoietic origin of round cell infiltrates in tissue sections.