PQA-18, an inhibitor of p21-activated kinase 2 (PAK2; IC50 = 10 nM), is derived from Ppc-1 (product number 42352) and exhibits immunosuppressive properties. It inhibits IL-2 production in Jurkat T cells induced by Concanavalin A (product number 14951) with an IC50 of 400 nM. Topically applied at 0.1%, PQA-18 reduces the severity of atopic dermatitis, serum IgE levels, and skin thickness in the NC/Nga mouse model. A lower concentration of 0.05% also decreases skin nerve fiber density in NC/Nga mice. Additionally, PQA-18 administered at 4 mg/kg improves graft survival in a rat small intestine transplantation model.