ULTRASTRUCTURAL IDENTIFICATION OF EXOCYTOSIS OF GRANULES FROM HUMAN GUT EOSINOPHILS IN-VIVO

Twenty-two percent of 117 biopsies of human intestinal tissues had ult rastructural images of classical regulated secretion from eosinophils in vivo i.e. eosinophil granule extrusion (EGE). Replicate intestinal biopsies that were positive for bacteria had EGE more often than not ( p < 0.05); 77% of the isolates were Staphylococci. Some of the intesti nal biopsies also had damaged nerves; all that had EGE and damaged ent eric nerves also had positive bacterial cultures. The EGE that we obse rved could not account for all enteric nerve damage, suggesting multif actorial mechanisms for nerve damage in gut tissues. Among the possibi lities are release of neurotoxic eosinophil granule proteins by an alt ernate secretory route, i.e., piecemeal degranulation, direct toxicity of tissue invasive bacteria and/or damaged nerves of unknown etiology such as those that are regularly present in uninvolved tissues of pat ients with Crohn's disease.