Formation of Charcot-Leyden crystals by human basophils.

Abstract

Basophils obtained from the peripheral blood of normal individuals were shown to form CLC [Charcot-Leyden crystals] and basophils were shown to contain a protein that is immunochemically indistinguishable from eosinophil CLC protein. These conclusions are based on the findings that crystal formation in basophils was demonstrated by specific histochemical staining of crystal-containing cells in highly enriched basophil suspensions prepared by fluorescence-activated cell sorter (FACS) purification of surface IgE-positive cells, that enrichment for surface IgE-positive cells (primarily basophils) by the FACS also enriched for cells staining positively by immunofluorescence for eosinophil CLC protein and that CLC protein was measured by radioimmunoassay in cell extracts prepared from purified basophil suspensions containing 97-99% basophils and absolutely no contaminating eosinophils. These basophil extracts contained a protein immunochemically indistinguishable from eosinophil CLC protein. Thus, the CLC or the protein comprising the crystal (lysophospholipase) can no longer be considered as distinctive to the eosinophil. The possibility that the presence of CLC in tissues, sputum or stool may also represent basophil involvement in disease processes must now be considered.