Objectives To analyze CPn0308 immunogenicity in the CPn infected patients with ICVD. Methods ①Clinical blood samples and separate plasma from blood and extract the DNA from PBMC were collected. ②The CPn IgG and CPn IgM were detected by using CPn specified diagnose kit. ③CPn DNA from PBMC was assayed by using PCR.④Imunogenicity of the endogenous CPn0308 was analyzed by Western Blotting. Results①Among the 70 patients with ICVD, the positive rate of CPn IgG was 51.43%, and it was higher than that of control; The positive rate of CPn IgM was 2.86%, and that of control was 8.47%. ②The positive rate of CPn DNA in PBMC from patients with ICVD was 81.08%，and it was higher than that of control. ③After plasma samples were diluted as 1:500, the antibodies to endogenous CPn0308 were still detected by using Western Blotting. The reaction was blocked after the plasma was pre-absorbed with GST-CPn0308 beads ahead, but not pre-absorbed with GST-CPn0186 beads. Conclusion ①There is an increase in the positive rate of CPn IgG in the patients with ICVD. ②The positive rate of CPn DNA in PBMC from the patients with ICVD is higher than that of the control. The positive rate for CPn by PCR is higher than that of EIA, and CPn DNA detection is a more sensitive method. ③The studies preliminarily demonstrate that CPn0308 has immunogenicity in the individual infected with CPn.