Langevitz et al. RA with Minocycline. Higher doses more effective. M Kloppenburg, H Mattie, N Douwes, BAC Dijkmans, FC Breedveld. Short-term antibiotic treatment has no effect in manifest ReA, whereas a tendency to improvement has been seen with treatment over months, at least after chlamydia infection.
Doxycycline disrupts chondrocyte differentiation and inhibits cartilage matrix degradation.
Best summary article with 39 references. Kloppenburg M et al. Minocycline in Rheumatoid arthritis. AM Beutler, HR Schumacher. Viruses and childhood arthritis.