- Cutting edge: susceptibility to psoriatic arthritis: influence of activating killer Ig-like receptor genes in the absence of specific HLA-C alleles. Martin, M.P., Nelson, G., Lee, J.H., Pellett, F., Gao, X., Wade, J., Wilson, M.J., Trowsdale, J., Gladman, D., Carrington, M. J. Immunol. (2002)