IL17A and chlamydia trachomatis infectious disease: In koalas, PBMC’s from those with chlamydial disease had greater gene expression for IL17A, but not IL10, IFNγ or TNFα, when stimulated with inactivated Chlamydia pecorum20, which may indicate that the Th17 response also plays an important role in immune-mediated chlamydial pathogenesis in that species.