HTLV-I associated and non-associated primary T-cell lymphoma of gastrointestinal tract.

The gastrointestinal (GI) tract is the common extranodal site for non-Hodgkin's lymphoma (NHL), and primary lymphoma of GI tract are mostly of B-cell origin. We have treated 16 patients with primary lymphoma of GI tract between 1981 and 1991, of whom 10 (62%) were of B-cell origin, while 6 (38%) were of T-cell origin. The incidence of T-cell phenotype in our hospital was considered to be much higher than that of previous reports and these 6 patients with primary T-cell lymphoma of GI tract were carefully studied. The primary sites were stomach in 4, ileocecum in 1, and duodenum in 1 case. Their T-cell nature was confirmed by immunohistochemical methods. All were peripheral T-cell lymphomas; one was CD 3+ 4- 8- and the other 5 were CD 3+ 4+ 8-. The antibody against human T-cell leukemia virus type I (HTLV-I) was positive in 3 cases (HTLV-I associated), but negative in 3 (HTLV-I non-associated). The integration of HTLV-I proviral DNA in HTLV-I associated patients was demonstrated by Southern blot analysis after DNA amplification by means of polymerase chain reaction (PCR). The clinical features of the HTLV-I associated and HTLV-I non-associated primary T-cell lymphoma of the GI tract were quite different. HTLV-I associated patients showed leukemic manifestations and tumor involvement of the skin at a later stage of the disease. These observations indicated that HTLV-I can play an important role in the occurrence of primary T-cell lymphoma of GI tract.