A Simple and Efficient Method for the Robust Expansion of Human ILC2s to Prevent Acute GvHD Open Access

• Activated human ILC2 limit GvHD and increase survival in xenograft models.

• IL-4 reduces ex-ILC2 generation during human ILC2 expansion.

Reconstitution of stem cells and enhancement of the barrier function of the gastrointestinal (GI) tract is critical to the resolution of intestinal acute graft-versus-host disease (aGvHD). Previously, our group has shown in murine models that type II innate lymphoid cells (ILC2) cells generate proteins in the GI tract that enhanced GI tract barrier function and diminished the expansion and function of pro-inflammatory donor cells when given to allogeneic stem cell transplant recipients. Therefore, the infusion of donor ILC2 cells could treat or prevent GI tract acute GvHD, but for this approach to be clinically applicable, robust expansion of a homogenous population of human ILC2 cells is needed. Here, we describe a method for the rapid expansion of a uniform population of human ILC2 cells which decrease GvHD in (NOD scid gamma mouse) NSG mice. The addition of IL-4 to the culture was critical to prevent the expansion of pro-inflammatory ILC1-like cells. Our approach should allow for the evaluation of human ILC2 cells to treat therapy-resistant GI tract acute GvHD.