Eosinophil infiltration and degranulation in normal human tissue

Abstract

Localization of eosinophil granule major basic protein by immunofluores-cence permits recognition of both eosinophil infiltration and degranulation. Over the past decade and a half, our laboratory has shown that eosinophil infiltration and degranulation occur in many diseased tissues in humans; among normal tissues studied as controls, only the gut showed striking eosinophil infiltration and degranulation. Using an indirect immunofluores-cence procedure for the detection of major basic protein, we extended our analyses of normal human tissues to include tissues from essentially all body organs; a total of 117 biopsy/autopsy specimens were analyzed. To determine whether the method of tissue procurement affected the level of eosinophil degranulation in the normal gastrointestinal tract, normal proximal jejunum from six patients was biopsied using either an endoscopic forceps or a scalpel at the time of elective surgery and examined by immunofluorescence. Spleen, lymph node, and thymus tissues showed eosinophil infiltration with scant evidence of degranulation, but the only organ showing both eosinophil infiltration and remarkable degranulation was the gastrointestinal tract. Eosinophil degranu-lation was significantly increased in specimens obtained by endoscopic forceps compared to those obtained by scalpel (P 0.021). These results indicate that tissue procurement methods affect the degree of eosinophil degranulation in the gut. Thus, among normal human body organs, both eosinophil infiltration and appreciable degranulation consistently occur only in the gut. Anat.

Cytokine mRNA abundance in intestinal biopsies from dogs with chronic diarrhea

“…The IL-5 stimulates and activates eosinophils (Lopez et al, 1988). Eosinophilic accumulation is a common feature of gastrointestinal disorders in human medicine (Rothenberg, 2004) and some categories of canine IBD (Allenspach and Gaschen, 2003), although eosinophilic infiltration can also be found in the normal gastrointestinal tract (Kato et al, 1998). Eosinophils have pleiotropic functions such as the release of preformed secondary granula, cytokines, chemokines, neuropeptides or lipid mediators.…”

Gastrointestinal Eosinophilia

“…[1] Notably, eosinophil infiltrations were only associated with eosinophil degranulation in the GI tract. Examination of eosinophils throughout the GI tract of conventional healthy mice (untreated mice maintained under pathogen-free conditions) has revealed that eosinophils are normally present in the lamina propria of the stomach, small intestine, cecum, and colon.…”

Established and Emerging Eosinophilic Gastrointestinal Diseases (EGIDs): Seeing Red and Looking Ahead

“…In an autopsy study, low-grade eosinophilic infiltration and degranulation in the gut was observed to occur in normal subjects although eosinophil counting (quantitative histology) was not performed [8]. In the present study by Alhmoud et al [1], the limit applied was [25 eosinophils/HPF in the proximal GI tract and 50/HPF in the colon.…”