A total of 27 (57.4%) RA patients, two (9.1%) with UPIA and one (3.2%) with other arthritides (one out the 10 affected by PsA), were positive for at least one tested autoantibody [ACPA, IgM rheumatoid factor (RF), and IgA RF]. Here, CD40LG is linked to rheumatoid arthritis.