MICROSCOPIC MEASUREMENT OF SYNOVIAL-MEMBRANE INFLAMMATION IN RHEUMATOID-ARTHRITIS - PROPOSALS FOR THE EVALUATION OF TISSUE SAMPLES BY QUANTITATIVE-ANALYSIS

Previous studies have used various techniques for microscopic analysis of rheumatoid synovium, ranging from rapid analysis of limited areas of tissue to detailed quantification of extensive areas. The sensitivi ty and reproducibility of these methods have not been tested. This stu dy sought to determine the minimum area of rheumatoid synovium needed to allow accurate microscopic analysis of synovial inflammation. Multi ple synovial tissue samples were obtained from patients with rheumatoi d arthritis at knee arthroplasty (n = 10), knee arthroscopy (n = 10) a nd by blind needle biopsy (n = 23). Lining layer thickness, sublining T-cell infiltration and vascularity were measured in all high-power fi elds (hpf) throughout every sample obtained from each patient. These c omplete measured results were compared with estimated results from lim ited numbers of hpf from each patient. It was observed that lining lay er thickness estimated from as few as five readings from 3 samples/pat ient correlated significantly with the measured results obtained from as many as 85 readings/patient [Tau (T) = 0.70-0.94 for the three grou ps, all P < 0.005). Estimated measures of T-cell infiltration and vasc ularity derived from only 17 randomly selected hpf from 3 samples/pati ent (equivalent to 1 mm(2)) correlated significantly with the measured results obtained from up to 150 hpf/patient (T = 0.65-0.94, all P les s than or equal to 0.002). Quantitative analysis of inflammation in sy novial tissue samples is both accurate and practical when restricted t o an evaluation of a limited number of microscopic fields. It is propo sed that lining layer thickness may be confidently quantified from fiv e randomly selected readings from three tissue samples, and that subli ning T-cell infiltration and vascularity may be quantified from 17 ran domly selected hpf from the same samples.