Enteropathy‐associated T‐cell lymphomas have a cytotoxic T‐cell phenotype

AIMS: Enteropathy-associated T-cell lymphoma (EATCL) is a rare complication of coeliac disease. We investigated whether EATCLs are the neoplastic counterparts of activated cytotoxic T-cells (CTLs). METHODS AND RESULTS: Eight cases, clinically and histologically defined, were stained with monoclonal antibodies against components of the cytotoxic granules of CTLs, granzyme B and T-cell restricted intracellular antigen (TIA-1). It was found that all cases had a cytotoxic phenotype, i.e. expression of TIA-1 in most of the tumour cells, whereas granzyme B was found in six of eight cases, mostly in a smaller number of tumour cells compared to TIA-1. Since TIA-1 and granzyme B are expressed at different stages of activation of CTLs it is hypothesized that differences in expression between granzyme B and TIA-1 in EATCL represent different stages of activation in which the tumour cells are arrested. Clinically, seven of the eight patients died within 10 months after diagnosis of EATCL. CONCLUSIONS: EATCL is a clinicopathological entity with a grim prognosis and with tumour cells representing a unique neoplastic equivalent of CTLs arrested in varying stages of activation.