PQA-18 is a unique PAK2 inhibitor (IC50: 10 nM) . PQA-18 has immunosuppressing effects. PQA-18 suppresses IL2, IL4, IL6, and TNFα. PQA-18 inhibits the population of a subset of regulatory T cells and the immunoglobulin (Ig) production against T cell-dependent antigens as well as alleviates dermatitis in mice[1].