In the early stage of the disease (4 dpi), elevated amounts of CXCL8 transcripts could be detected in BALF cells of infected animals, thus corroborating the hypothesis that IL-8 is produced in C. psittaci-infected tissue to recruit and activate neutrophils [51], as in other chlamydial infections [52–54]. This evidence concerns the gene CXCL8 and chlamydia trachomatis infectious disease.