EOSINOPHILS ARE AN INSIGNIFICANT CELLULAR-COMPONENT OF RHEUMATOID SYNOVIUM IN PATIENTS WITH LATE-STAGE DISEASE - COMPARATIVE DISTRIBUTIONS WITH MAST-CELLS AND MACROPHAGES

Objectives-To examine the distribution of eosinophils in rheumatoid sy novial tissue and to determine whether or not their tissue distributio n is related to that of mast cells or macrophages. Methods-Consecutive tissue sections from 31 specimens of rheumatoid synovial tissue and c artilage-pannus junction were stained for eosinophils, mast cells, and macrophages with monoclonal antibodies and immunolocalisation techniq ues. Results-Eosinophils were absent in 28 of the 31 specimens; the re maining three showed only the occasional eosinophil. By contrast the m ean values for mast cell and macrophage (CD68/KP1 marker) distribution s were 24 (SD 22) and 104 (SD 66) per mm(2), respectively. Conclusion- There are very few eosinophils in inflamed rheumatoid sites of cartila ge and the presence of appreciable numbers of macrophages and mast cel ls, the mast cells showing various states of activation. Such findings are at variance with those in allergic inflammation, in which the pre sence of eosinophils has been reported to regulated by specific chemok ines adhesion molecules.