Synovial membrane in early rheumatoid arthritis: clinicomorphological comparisons

Aim. To evaluate implications of pathomorphological alterations of synovial membrane at an early stage of rheumatoid synovitis (RS) for further course of rheumatoid arthritis (RA) and prognosis of the disease.
Material and methods. 92 new cases of RA (22 males, 70 females, mean age 31.1 + 10.5 years, mean duration of RA 5.99 ± 3.27) subjected to puncture biopsy of the synovial membrane of the knee joint in 1967-1983. At admission to hospital 54.3, 45.7 and 29.3% patients had polyarthritis, monoand oligoarthritis, rheumatoid factor, respectively. The RA diagnosis was confirmed in 68 (73.9%) patients, 26 (28.3%) of them were observed for 1-2 years, 42 (45.6%) -for 11.8 + 8.8 years, on the average. In 9 (9.8%) patients the diagnosis was changed for Bechterew's disease (n = 6), polymyositis (n - 1), rheumatism (n = 1), reactive arthritis (n = 1), 15 (16.3%) patients with seronegative oligoarthritis of large joints were lost for follow-up. Now (the beginning of 2002) synovial biopsies were investigated in "blind" mode by one morphologist (using the semiquantitative method) and compared to clinical and x-ray evidence.
Results. The most frequent changes were the following: proliferation of lining synovial cells (82.6%), lymphoid infiltration (64.1%), angiomatosis (60.9%), fibrinoid changes (60.9%). Accumulation of large amounts of macrophages and lymphocytes in the infiltrate was detected in RA significantly more often than in non-RA patients. Among 68 patients with definite RA morphological picture in biopsies obtained from the knee joints with manifest synovitis (69.1%) and from clinically intact joints (30.9%) was practically the same. The most important morphological sign was angiomatosis associated with early polyarticular involvement, early development of joint erosions and early disability (patients with marked angiomatosis were disabled after 4 years of illness, on the average, without angiomatosis - after 11 years). Statistically significant associations of parameters of RA development with other histological signs of synovitis were not detected.
Conclusion. Angiomatosis in the synovial membrane occurs at early (including preclinical) stages of RA and, as a manifestation of angiogenesis, is an unfavorable prognostic factor of early polyarticular involvement, early development of joint erosions and early disability. Synovial biopsy at an early stage of arthritis is of differential-diagnostic value and helps to define a long-term outcome. Therefore, synovial biopsy of the knee joint must be in the list of standard examinations of patients with early RA.

rheumatoid arthritis, synovitis, angiogenesis, prognosis