... M,Nagasaki M, Nakayama-Hamada M, Kawaida R, Ono M, OhtsukiM, Furukawa H, Yoshino S, Yukioka M, Tohma S, Matsubara T,Wakitani S, Teshima R, Nishioka Y, Sekine A, Iida A, Takahashi A, Tsunoda ... Silman AJ: The perfor-mance of the 1987 ARA classification criteria for rheumatoidarthritis in a population based cohort of patients with earlyinflammatory polyarthritis. American Rheumatism Associa-tion. ... [6].Also, rheumatoid nodules are very rare in the early phases of RA, and rheumatoid factor is present in only 50% of the patients with early RA [7].Conversely, the serological factor that has the...