Cell therapy with IL-10-producing group 2 innate lymphoid cells suppresses Graft-versus-Host disease

IL-10 producing group 2 innate lymphoid cells (ILC210) have immunoregulatory functions, and limit harmful immune responses across various tissues. Despite their crucial roles in maintaining immune homeostasis, the cell therapy potential of human ILC210 has not been demonstrated, due to both limited numbers in human peripheral blood and lack of definitive markers for identification. Here, we isolate and expand circulating human ILC210, and assess their cell therapy potential in a humanized model of Graft-versus-Host Disease (GVHD). Cell therapy with human ILC210 decreased GVHD severity and prolonged survival of NOD- scid IL2Rγnull (NSG) mice. Adoptive transfer of ILC210 inhibited pathogenic T cell proliferation and intestinal infiltration, and suppressed CD4+ Th1 and CD8+ Tc1 cells in an IL-4 and IL-10 dependent manner. Critically, increased proportions of ILC2s did not correlate with higher rates of cancer relapse in HSCT recipients, and adoptive transfer of ILC210 did not compromise graft-versus-leukemic (GVL) effects in a humanized model. Finally, we identify CD49d and CD86 as novel markers that discriminate ILC210 from conventional ILC2s. Collectively, these findings demonstrate the potential of harnessing ILC210 in cell therapies for GVHD and other immune-driven pathologies. ### Competing Interest Statement Authors declare that they have no competing financial interests. KTR, SJC, JAM, JMM and SQC have filed a provisional patent for human ILC expansion methods (Provisional Patent Application#: 63/353,823) and KTR, SJC, WC and SQC have filed a provisional patent for marker combinations for ILC210 isolation (Provisional Patent Application#: 63/469,234) * ADT : Antibody derived tags aGVHD : Acute Graft-Versus-Host Disease AML : Acute myeloid leukemia BMT : Bone marrow transplant CBA : Cytometric Bead Array CITE-Seq : Cellular Indexing of Transcriptomes and Epitopes by Sequencing EOMES : Eomesodermin FACS : Fluorescence Activated Cell Sorting GVL : Graft-Versus-Leukemia Effect HSCT : Hematopoietic Stem Cell Transplant IHC : Immunohistochemistry IL : Interleukin ILCs : innate lymphoid cells ILC1 : Group 1 innate lymphoid cells ILC2 : Group 2 innate lymphoid cells ILC210 : IL-10-producing ILC2s ILC3 : Group 3 innate lymphoid cells KIR : Killer Cell Immunoglobulin-like Receptors LTi : Lymphoid Tissue Inducer Cells MDSC : Myeloid derived suppressor cell MSC : Mesenchymal stromal cell NK Cells : Natural Killer cells NSG : NOD-scid-IL2Rgnull PMA : Phorbol 12-myristate 13-acetate RT : Room Temperature S.I. : Small Intestine sLT : Surface Lymphotoxin Tc1 : Cytotoxic T cell type 1 TGF-β : Transforming Growth Factor Beta Th1 : T helper 1 Th17 : T helper 17 Tc1 : Type 1 CD8+ cytotoxic T cell Tr1 : Type 1 Regulatory T cell Treg : Regulatory T cell XenoGVHD : Xenogeneic Graft-versus-Host Disease