Evidence of T-Cell Oligoclonality in a Retrospective Series of Enteropathy-Associated T-Cell Lymphomas (EATLS) and Ulcerative Jujunitis Using RNA Extracted from Formalin-Fixed Paraffin-Embedded Tissue

Aims: To analyse the T-cell receptor Vβ (TCR Vβ) repertoire in a series of formalin- fixed paraffin embedded tissue blocks from patients diagnosed with enteropathy associated T-cell lymphoma (EATL) or with ulcerative jejunitis (UJ), by reverse transcription polymerase chain reaction (RT-PCR) and by complementarity determining region 3 (CDR3) spectratyping.

Methods: Intestinal tissue blocks (n=61) were obtained from (a) 4 normal (n=11), (b) 5 EATL patients (n=42) and (c) 4 patients with UJ/EATL (n=6). RNA and DNA were simultaneously isolated from 56 blocks. The TCR Vβ repertoire was analysed using semi-nested RT-PCR and the products were further analysed by CDR3 spectratyping. DNA was also analysed using TCR γ primers.

Results: The normal controls contained oligoclonal populations comprising a number of TCR Vβ families. Oligoclonal T-cell populations comprising fewer T cell families were observed in the EATL blocks, with TCR Vβ 9,15 and 21 being the most common. Significantly, TCR Vβ9 was expressed in 81% of the EATL blocks. All blocks of ulcerated tissue from both UJ or EATL patients expressed TCR Vβ9.

Conclusions: Oligoclonal T cell populations were observed in all groups tested but with fewer TCR Vβ families in the EATL patients and even fewer in the ulcerated tissue from both the EATL and UJ patients. Significantly, a TCR Vβ9 expressing family was observed in the majority of the EATL blocks and in all of the ulcerated tissue blocks. This T cell subpopulation may be of importance in the pathogenesis of EATL.