Our study revealed that the monocyte expression of CR3 (CD11b), CR4 (CD11c) and CD59 is significantly reduced in DENV-infected patients, whereas plasma levels of SC5b-9 are elevated, markedly so in patients with pronounced haemorrhagic manifestations and vascular leakage, suggests that complement activation is strongly linked to unfavourable outcomes in dengue. The gene discussed is CD59; the disease is dengue disease.