- Increased C5a receptor expression in sepsis. Riedemann, N.C., Guo, R.F., Neff, T.A., Laudes, I.J., Keller, K.A., Sarma, V.J., Markiewski, M.M., Mastellos, D., Strey, C.W., Pierson, C.L., Lambris, J.D., Zetoune, F.S., Ward, P.A. J. Clin. Invest. (2002)