Refractory coeliac disease type II (RCDII) is characterized by a continuous
gluten-independent duodenal immune activation with an extremely high risk of malignant transformation. It is therefore considered as an indolent
lymphoma. RCDII is characterized by the presence of villous
atrophy (Marsh III A-C) in combination with an aberrant intra- epithelial lymphocyte (IEL) population consisting of >20% sCD3-CD7+iCD3+ IELs. The sCD3-CD7+iCD3+ IELs are a heterogeneous lineage-negative cell population, consisting of cells that do or do not express CD127/IL7Rα. Experiments using IEL from non-RCDII patients have indicated that while the CD127- cells are
IL-15 responsive, the CD127+ cells are not. Together with the observation that some patients express an aberrant (monoclonal) TCRγδ phenotype, this confirms the heterogeneity of the aberrant IEL population in RCDII and suggests that the aberrant cells are heterogeneous with respect to their response to common γ-chain
cytokines. Although
cladribine with or without autologous
stem cell transplantation is effective in the treatment of signs and symptoms of RCDII and improves survival as compared to symptomatic topical
steroid therapy,
cladribine failures still bear a high risk of malignant transformation, and the rate of
enteropathy-associated T-cell lymphoma (EATL) development in this subgroup is extremely high. It might be hypothesized that the heterogenous nature of aberrant IEL and the high risk of malignant transformation require a treatment strategy which is effective despite this heterogeneity. RCDII should be seen more in the light of a low-grade/no mass
lymphoma or pre-EATL. We would suggest an upfront combination
therapy approach integrating inhibition of downstream Jak-STAT signalling pathways with conventional
therapy (2-CDA) to hopefully effectively treat signs and symptoms of RCDII and accomplish a more effective EATL prevention.