DOES SERUM RHEUMATOID-FACTOR HAVE AN INFLUENCE ON THE CLINICAL PICTURE OF ANKYLOSING-SPONDYLITIS

Objective: To describe the influence of serum rheumatoid factor (RF) o n the clinical and radiological picture of definite ankylosing spondyl itis (AS). Methods: In a retrospective chart review of 281 AS patients typed for RF, the clinical picture of RF positive patients (Group 1) was compared with RF negative patients (Group 2); mode of onset, disea se duration, and treatment were recorded. All patients were examined t o determine their clinical status; the blood cell count, HLA-B27, seru m IgG, IgM, IgA, and erythrocyte sedimentation rate (ESR) were determi ned, and radiological studies of the entire spine, pelvis and affected peripheral joints were carried out. In patients from Group 1 the HLA- DR was also determined. Results: Fifteen of 281 patients (8 men, 7 wom en) with AS were RF+ (1:64 to 1:1024) (5.3%) and 11 were HLA-B27+. Sev en patients in Group 1 had spine involvement and chronic arthritis of the knees. Four out of these 7 were tested for DR, and none was positi ve; in 6, AS and rheumatoid arthritis (RA) coexisted, 2 were DR1 and 2 were DR4 (test not carried our in 2). In two others we found spinal i nvolvement only, and one of them had both DR1 and DR4. The onset of AS was similar in both groups. Group 1 was characterized by a chronic di sease of moderate intensity with chronic arthritis of the metacarpopha langeal and proximal interphalangeal joints (p=0.0008 and p=0.04, resp ectively), no valvulopathy (p=0.04) and fewer uveitis sequelae (p=0.00 7) than Group 2. The ESR (p=0.01), IgG (p=0.008) and IgM (p=0.0001) we re higher in Group 1 than in Group 2. Conclusions: The presence of RF in AS is associated with a chronic disease of moderate intensity with chronic peripheral arthritis and fewer extra-articular manifestations, The presence of RF, not always associated with HLA-DR, seems to affec t the course of AS and does not necessarily indicate an association wi th RA.