Finally, CDH11<sup>+</sup>neutrophils were identified in close proximity to synovial fibroblasts by confocal microscopy in knee-surgery-obtained rheumatoid synovium.<h4>Conclusions</h4>Combining our findings with previous data showing circulating pre-inflammatory mesenchymal cells preceding rheumatoid arthritis flares, we propose that a chemokine-orchestrated process, that seems to not being affected by short-term Disease-Modifying Antirheumatic Drug (DMARD) treatment, may contribute to 'arthritis spreading' in both RA and PsA. This evidence concerns the gene CDH11 and arthritic joint disease.