Abstract
Although rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are intractable diseases due to persistent chronic inflammation, AS showing close association with HLA-B27, negative test for rheumatoid factor and radiologic sacroilitis was demarcated from RA in the newest classification of the rheumatic diseases by the American Rheumatism Association. However, histopathological differences between RA and AS remain unclear.
For purposes of comparison of inflammatory features in the joints from both diseases, 28 autopsies and 35 biopsies from patients with seropositive RA and 1 autopsy and 4 biopsies from patients with AS were studied histopathologically.
The following results were obtained: villous hyperplasia of the synovium, synovial lining cell hyperplasia, superficial fibrin deposition were found in both diseases. But scanty plasma cell infiltration around lymphoid cell aggregation, strong tendency to granulomatous inflammation accompanied by ossification and absence of rheumatoid nodules in the articular tissues of AS were distinct from RA.
These studies suggest that histopathological differences between RA and AS may be due to disparity of immunological background in both diseases.
