STUDY OF THE IMMUNOHISTOCHEMISTRY AND T-CELL CLONALITY OF ENTEROPATHY-ASSOCIATED T-CELL LYMPHOMA

Specimens from 23 patients with enteropathy-associated T cell lymphoma were studied by immunohistochemistry after antigen retrieval Specimen s from 14 of these patients were investigated for the presence of clon al T cell gene rearrangements in both the tumor and the adjacent enter opathic intestine by the polymerase chain reaction. Primers for T cell receptor beta and gamma genes were used in a combination that permits the identification of approximately 90% of T cell receptor rearrangem ents. Clonal rearrangements of the T cell receptor were found in 13 of the 14 tumors studied Specimens of enteropathic bowel resected with t he tumor, but showing no morphological or immunohistochemical evidence of tumor involvement, showed clonal T cell receptor gene rearrangemen ts in 11 cases. In 10 of these, the amplified DNA was of the same mole cular weight in the enteropathic bowel as in the corresponding tumor. In 2 cases, sequencing the polymerase chain reaction product showed id entical T cell receptor gene rearrangements in the tumor and in the ad jacent intestine. Uniform staining for p53 was seen in 22 of the 23 tu mors, In 9 of 19 cases studied, collections of small lymphocytes in th e enteropathic bowel expressed p53. In all but one of these specimens, a clonal rearrangement of the T cell receptor genes was identified. W e interpret these findings as support for the concept that enteropathy -associated T cell lymphoma arises on a background of gluten-sensitive enteropathy with evolution of neoplastic T cell clones from the react ive T cell population present in the enteropathic bowel.