Genes within the human IBD ‘Immune effector’ module were found to be largely expressed in the ‘B cells 1’, ‘macrophage/myeloid leukocyte’, ‘T cells Ctla4 high’ and ‘T cells Icos high’ in the mouse LPL scRNA-seq clusters from infected Prdm1fl/fCd4Cre mice and to a greater extent the Maffl/flCd4Cre and double-deficient Prdm1fl/fMaffl/flCd4Cre mice (Fig. 7d). The gene discussed is ICOS; the disease is inflammatory bowel disease.