Formation of Charcot-Leyden crystals by human basophils in sputum and peripheral blood

To confirm the formation of Charcot-Leyden crystals (CLC) in basophils, we observed basophils in sputum and peripheral blood. Sealed slide and suspension culture methods were used to observe the process of CLC formation in peripheral blood basophils and eosinophils under electron microscopy. CLC formation was observed in basophils and eosinophils, and was found to be augmented by sealed slide method. A temperature of 4 degrees C was better than 37 degrees C for promoting the formation of crystals. There was no correlation between the degranulation of these cells and the formation of CLC after stimulation with anti-IgE or anti-IgG antibodies. CLC were initially detected in the cytoplasmic granules of basophils where they continued to enlarge. No CLC were identified in mast cells under any conditions studied. These findings confirm that CLC in sputum are not exclusive to eosinophils and that CLC appear to be present in basophil-rich sites under the cell damage.