Objective To investigate potential mechanisms by which CD40-CD40 ligand (CD40L, CD154) interaction may be involved in the pathogenesis of immunodeficiency and renal injury in haemodialysis patients. Methods Soluble CD40 and CD154 on CD4+T cells was detected in the serum of haemodialysis patients (n=22) and healthy donors (n=10) by the method of ELISA and two color flow cytometry, respectively. Results Soluble CD40 was detected in the serum of haemodialysis patients with a mean of(781.22± 203.03)pg/ml，significantly higher than healthy donors(30.28±11.09)pg/ml, P<0.01; CD154 on CD4+T cells was detected in the serum of haemodial ysis patients with a mean of （41.41±5.54）%，elevated comparing with healthy donors (29.24±3.99)%, P<0.05. CD40-CD40 ligand (CD40L) interaction may be actiatved in haemodialysis patients. Conclusion CD40-CD154 may be involved in the pathogenesis of uremia by the means of immunodeficiency and renal injury.