Background: The present study was undertaken to develop an in-house enzyme-linked immunosorbent assay (ELISA) using human leukocyte antigen class II restricted epitopes to test circulating autoantibodies to CD25 as a biomarker for esophageal cancer.
Methods: A total of 97 patients with esophageal squamous cell carcinoma (ESCC) and 226 healthy subjects were recruited for this study and their plasma samples were collected for antibody analysis with the ELISA approach.
Results: Mann-Whitney U test showed that the IgG anti-CD25 antibody level was significantly higher in the patient group than the control group (P < 0.001) while the IgA antibody level was not significantly different between these two groups (P = 0.361). Spearman correlation analysis failed to reveal a significant correlation between the levels of anti-CD25 IgG and IgA antibodies in either the patient group (r = -0.027, P = 0.797, n = 94) or the control group (r = 0.055, P = 0.429, n = 209). The sensitivity against >90 % specificity was 37.2 % for the IgG assay with an inter-assay deviation of 9.4 %, and 8.2 % for the IgA assay with an inter-assay deviation of 13.0 %. Based on a cut-off value determined by the 99th percentile of control IgG levels, the positive rate was 7.4 % in patients with ESCC, in which patients at stage I had the highest positivity (11.5 %) (χ (2) = 11.10, P = 0.001, OR = 12.12, 95 % CI 1.93-75.94).
Conclusions: This work suggests that circulating IgG autoantibody to CD25 may be a potential biomarker for early diagnosis of esophageal cancer.