Electron microscopy of the microangiopathy and immunohistochemistry of the inflammatory infiltrate in eosinophilia-myalgia syndrome

Abstract

The ingestion of L-tryptophan (LT) was linked with the eosinophilia-myalgia syndrome (EMS) in the fall of 1989. The pathology is a microangiopathy consisting of endothelial cell dysfunction and invasion of blood vessels by lymphocytes. Perimysial, fascial, and dermal perivascular lymphocytes and eosinophils are present. A contaminant in the manufacturing process of LT has been identified as the di-L-tryptophan aminal of acetaldehyde. This report describes the electron microscopic appearance of the microangiopathy and the phenotyping of the inflammatory infiltrate by immunohistochemistry.Muscle, fascia, and skin biopsies from 21 affected individuals were rapidly frozen for light microscopy, histochemistry, and immunohistochemistry. For electron microscopy tissues were preserved in 4% formaldehyde-1% glutaraldehyde with post-fixation in osmium tetroxide. Thin sections were stained with uranyl acetate and lead citrate and examined in a JEOL 100CX electron microscope. Eight anlisera were used for the immunohistochemistry to identify lymphocyte subsets and macrophages. The markers were CD-2 (pan T), CD-3 (pan T), CD-4 (T helper), CD-5 (T helper), CD-8 (T suppressor), CD-19 (B cell), CD- 22 (B cell), and CD-68 (macrophage). Three high power fields were examined from the dermis, fascia, and muscle from eight biopsies counting the immunoperoxidase labelled cells for each marker.