High myeloid‐derived suppressor cell frequencies in the duodenum are associated with enteropathy associated T‐cell lymphoma and its precursor lesions

Enteropathy-associated T-cell lymphoma (EATL) is an extra-nodal T-cell non-Hodgkin lymphoma originating from intestinal intraepithelial T-lymphocytes (IEL). EATL is associated with coeliac disease (CD), which is a gluten sensitive enteropathy that is normally successfully treated with a gluten free diet (GFD). However, 2–3% of adult onset CD patients develop refractory CD type II (RCDII), which is characterized by clonal expansion of surface CD3 negative, cytoplasmic CD3 positive IEL (Rubio-Tapia et al, 2009). This aberrant cell population is believed to be at the origin of EATL (Daum et al, 2000), developing in c.50% of RCDII patients. Despite aggressive therapy, clinical outcome of EATL patients is poor, with a 5-year survival rate of 15%. Therefore, it is important to identify patients at risk for EATL development to justify early aggressive treatment, before EATL arises (Al-Toma et al, 2007). Myeloid-derived suppressor cells (MDSC) are immature myeloid cells that fail to terminally differentiate into granulocytes, monocytes or dendritic cells, but rather acquire immune suppressive abilities. Human granulocytic (gr-) MDSC are CD11bCD15CD33 and monocytic (mono-) MDSC are CD14HLA-DR . MDSC exert immunosuppressive capabilities via the expression of, among others,