2026 Volume 15 Issue 2 Article ID: 25-050
We compared the positivity rates of Chlamydia pneumoniae (Cpn) IgA and IgG antibodies in a total of 158 patients from a group with idiopathic pulmonary fibrosis (IPF), a control group, a group with bacterial pneumonia, and a group with non-IPF interstitial lung disease (non-IPF ILD). The Cpn IgA antibody positivity rate was significantly higher in the IPF group than in the control group, and this difference remained significant even after adjusting for age, sex, and smoking history. The non-IPF ILD group also showed elevated levels after adjustment. However, there was no significant difference in the Cpn IgG antibody positivity rate between the groups. The involvement of the elevated Cpn IgA antibody positivity rates in the pathogenesis requires further investigation.
