The haemolysis rates of C. perfringens septicaemia clinical isolates were shown to strongly correlate with PFO expression alone, regardless of α-toxin production (whereas a pfoA-deficient strain did not induce haemolysis), with proinflammatory cytokine production (TNF-α, interleukin IL-5 and IL-6) significantly stronger than α-toxin40. The gene discussed is IL5; the disease is Sepsis.