Approach to patients with refractory coeliac disease

Refractory coeliac disease (RCD) is a recognised complication, albeit very rare, of coeliac disease (CD). This condition is described when individuals with CD continue to experience enteropathy and subsequent or ongoing malabsorption despite strict adherence to a diet devoid of gluten for at least 12 months and when all other causes mimicking this condition are excluded. Depending on the T-cell morphology and T-cell receptor (TCR) clonality at the β/γ loci, RCD can be subdivided into type 1 (normal intra-epithelial lymphocyte morphology, polyclonal TCR population) and type 2 (aberrant IELs with clonal TCR). It is important to differentiate between the two types as type 1 has an 80% survival rate and is managed with strict nutritional and pharmacological management. RCD type 2 on the other hand has a 5-year mortality of 50% and can be complicated by ulcerative jejunitis or enteropathy-associated T-cell lymphoma (EATL). Management of RCD type 2 has challenged many experts, and different treatment approaches have been adopted with variable results. Some of these treatments include immunomodulation with azathioprine and steroids, methotrexate, cyclosporine, alemtuzumab (an anti CD-52 monoclonal antibody), and cladribine or fludarabine sometimes with autologous stem cell transplantation. In this article, we summarise the management approach to patients with RCD type 2.

Therapy in RCDII: Rationale for Combination Strategies?

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.