Thread by @BASHH_UK

Time for the keynote speech from #PaddyHorner: Is there a hidden burden of disease as a result of epigenetic epithelial-to-mesenchymal transition following chlamydial genital infection? #vBASHH21

Life cycle of Chlamydia trachomatis:

Not a trifling STI: #chlamydia #vBASHH21

What causes persisting problems? Probably a prolonged pro-inflammatory state but evidence unclear. #vBASHH21

*All* PID has gone down since introduction of national <25 Chlamydia screening in 2008. But why? Incidental treating of mixed organisms in upper genital tract? #vBASHH21

But *any* hx of previous CT is a risk factor for future PID, tubal infertility. Why? Confounders? Or has the damage already been done early on in infection? #vBASHH21

The higher the anti-chlamydial antibody titre, the higher the risk of tubal/pelvic damage. Immunological cause? #vBASHH21

The research revealed 4 categories of antibody titres, corresponding with history:

Associations described between CT history and cervical/ovarian cancers - though unclear re causality (likely confounder of increased sexual partner number for cervical Ca etc)

An explanation of epithelial to mesenchymal transition as part of tissue healing #vBASHH21

Epigenetics: hot topic of much research, how genes are 'switched on' or 'off' #vBASHH21

So Chlamydia invades host cells and changes the cell architecture and DNA transcription, inducing this EMT process. Clever! #vBASHH21

The host's epithelial homeostatic defences can clear the Chlamydial infection eventually, but epigenetic alteration may persist long after the infection is gone. Is this how longterm adverse sequelae come about? #vBASHH21

These pro inflammatory changes may explain why some people suffer chronic post-infection pain and symptoms, better than the historic belief that damage arises from years-long undiagnosed infection

Similarly with increased risk of ectopics: #vBASHH21

EMT phenotypes seen in ovarian Ca precursors. Could also be a cofactor in anorectal carcinoma and trachoma. So should we be scaling up our prevalence reduction measures? Time and research will tell. #vBASHH21