Abstract
Background
Acute graft-versus-host disease (aGVHD) is one of the most common causes of morbidity for patients undergoing allogeneic stem cell transplantation. There is preliminary evidence that activated Group 2 innate lymphoid cells (ILC2s) from wild type (WT) mice reduces the lethality of aGVHD and is effective in treating lower gastrointestinal (GI) tract manifestations of aGVHD. This raises the prospect that ILC2s may be used for cell-based therapy of aGVHD but vigorous investigation is necessary to assess their impacts on different aspects of aGVHD. Genetically engineered mice which either express Id1 protein (Id1tg/tg), an inhibitor of E protein transcription factors or have E protein genes knocked out (dKO) in the thymus produce massive numbers of ILC2s, thus allowing extensive evaluation of ILC2s. We investigated whether these ILC2s have protective effects in aGVHD as WT ILC2s do using an established mouse model of aGVHD.
Results
bone marrow transplant was performed by irradiating BALB/c strain of recipient mice and transplanting with bone marrow and T cells from the MHC-disparate C57BL/6 strain. We isolated ILC2s from Id1tg/tg and dKO mice and co-transplanted them to study their effects. Our results confirm that activated ILC2s have a protective role in aGVHD, but the effects varied depending on the origin of ILC2s. Co-transplantation of ILC2s from Id1tg/tg mice were beneficial in aGVHD and are especially helpful in ameliorating the skin manifestations of aGVHD. However, ILC2s from dKO mice were less effective at the protection and behaved differently depending on if the cells were isolated from dKO mice were pre-treated with IL-25 in vivo.
Conclusion
These findings support the notion that thymus-derived ILC2s from Id1tg/tg mice are protective against aGVHD, with a significant improvement of skin lesions and they behave differently from dKO mice in the setting of aGVHD.
Type 2 innate lymphoid cells treat and prevent acute gastrointestinal graft-versus-host disease
