Preferential type 1–1 cytokine gene expressions in peripheral T‐cell lymphomas

In this study, we have investigated whether a pattern of cytokine gene expression can be found in non-Hodgkin's peripheral T-cell lymphoma (PTCL). By using RNase protection assays and RT-PCR, we have systematically studied IL1α, IL1β, IL1-Ra, IL2, IL4, IL5, IL6, IL9, IL10, IL12p35, IL12p40, IL13, IL14, IL15, IFNγ, IFNβ, TNFα, TNFβ, LTβ, and TGFβ1, TGFβ2 and TGFβ3. Twenty-two cases of PTCL inclusive of three nasal NK-cell lymphomas were selected for the study; three cases of reactive lymphoproliferation were included for comparison. Results show that IFNγ gene expression (key Type 1 cytokine) was frequently detected [18/22 (82 per cent)]. In contrast, IL4 (key Type 2 cytokine) was only detected in 4/22 (18 per cent) of cases (weaker than IFNγ in three cases). This distinction was also found at the protein level by immunohistochemistry. In addition, TNFβ and TNFα (strongly expressed by Type 1 cells) were almost complimentarily detected [4/19 (21 per cent)] and 12/19 (63 per cent), respectively). In contrast, neither IL5 nor IL13 (strongly expressed by Type 2 cells) were detected at all. However, 14/22 cases expressed IL10, another Type 2 cytokine, which suggests that the autoregulatory feedback loop is stimulated. Compared to the tumour types, the cytokine profiles in the reactive lymphoproliferative types also resembled a Type 1‒like pattern but was less striking. The overall result suggested a preferential expression of certain cytokines, and these cytokines may play an important role in pathophysiologic progression in these T-cell disorders. Copyright © 1999 John Wiley & Sons, Ltd.