HLA B27 in rheumatoid factor-negative polyarthritis.

Eighty-three consecutive patients with rheumatoid factor-negative polyarthritis seen during a 1-year period were evaluated clinically, radiologically, and with the B27 test. Patients with definite spondylitis, juvenile chronic polyarthritis, a collagen disease, a known metabolic arthropathy, or primary generalized osteoarthritis were excluded. The patients could be classified into two groups independent of any knowledge of B27 testing. Twenty-five had a spondylitic "variant" syndrome. These could be diagnosed on clinical grounds, and included a male preponderance and a high frequency of B27 positivity. Fifty-eight patients, who could generally be classified by American Rheumatism Association criteria as having definite or classic rheumatoid arthritis, included a female preponderance and a normal prevalence of B27. Thus the B27 test was not more helpful than clinical diagnosis in the classic spondylitic variant syndromes, nor did it separate out a population of patients from among the seronegative rheumatoid arthritis group.