Histology of the synovial tissue: value of semiquantitative analysis for the prediction of joint erosions in rheumatoid arthritis.

Routine histologic techniques are still the main procedure in the study of the synovial biopsy. The relationship between the typical histological changes of rheumatoid synovium and clinical manifestations has not been studied in detail.With the aim of determining whether a simple semiquantitative method of evaluating the changes in closed synovial biopsies was of clinical value in assessing both the diagnosis and prognosis of rheumatoid arthritis (RA) patients, we evaluated retrospectively 72 synovial biopsy specimens (26 RA patients, 30 patients with other inflammatory diseases and 16 osteoarthritis patients). Scores (0-10) were assigned to each biopsy specimen for each of 6 histologic features: synoviocyte hyperplasia; fibrosis in the subsynovial layer; proliferating blood vessels; perivascular infiltrates of lymphocytes; focal aggregates of lymphocytes; and diffuse infiltrates of lymphocytes. Scores were compared between the 3 groups and also between the RA subgroups with early and late disease; positive and negative rheumatoid factor; with and without joint erosions; and with and without systemic disease.Significant differences in the mean global score (mean of the 6 scores) were found both between RA and osteoarthritis and between other inflammatory diseases and osteoarthritis (p < 0.01). The mean global score for RA was higher than the mean global score obtained for the other inflammatory diseases, but the difference was not significant. We found a significantly higher mean global score in the RA patients with erosions in comparison to the RA patients without erosions, this difference being particularly evident for the lymphocyte perivascular infiltrate (p < 0.05). There were no significant differences between the other RA subgroups.In this study we have identified differences, using routine histologic techniques, between the rheumatoid synovial membrane of patients with and without erosions. Based on our present observations we suggest that the intensity of inflammatory histological features and, in particular, a high percentage of vessels with perivascular lymphocyte infiltrate might be of prognostic value in RA.