Mast cells in surgically resected appendices.

Mast cells are known to be effector cells in various inflammatory reactions, but their role in appendicitis is unclear. The present study was undertaken to investigate the extent of mast cell involvement in appendicitis and evaluate their possible role. A total of 150 appendices including normal and inflamed appendices, were assessed for their histological changes and density of neutrophil, lymphocyte and eosinophil infiltration. The mast cells were counted in 1% toluidine blue-stained sections. It was found that eosinophil counts in all the layers were significantly low in normal appendices (P<0.01) and in chronic appendicitis (P<0.1) as compared to acute appendicitis. Mast cell counts were lowest in normal appendices, significantly higher in acute appendicitis (P<0.01) and highest in chronic appendicitis (P<0.001). Obstruction due to faecoliths or parasites were seen in only 20.1% and 2.1% of the inflamed appendices respectively. Hence a Type I hypersensitivity reaction with release of mediators by mast cells might be another triggering factor for the sequence of events leading to appendicitis.

Células enteroendocrinas intraepiteliales en ciego y apéndice de conejos sensibilizados con ovoalbumina / Intraepithelial enteroendocrine cells in cecum and appendix from ovalbumin sensitized rabbits

Las células enteroendócrinas se relacionan con la motilidad, secreción y absorción de nutrientes. Actualmente está en estudio su relación con la respuesta inmune. El ciego y el apéndice del conejo, contienen en su luz bacterias y nutrientes en distintas etapas de digestión, con potencial acción antígenica. En el presente trabajo se evalúan las modificaciones en número y distribución de las células enteroendócrinas intraepiteliales en ciego y apéndice cecal de conejos sensibilizados con ovoalbúmina (OVA). Se utilizaron conejos neozelandeses adultos divididos en dos grupos, G1: grupo control (n=10). G2: sensibilizados vía intraperitoneal con OVA (n=10). Muestra de ciego y apéndice se fijaron en formol buffer al 10 por ciento marcándose las células enteroendócrinas con anticuerpo monoclonal anti-cromogranina A. En cada animal se contaron 400 campos microscópicos a mayor aumento, refiriéndose el número de células enteroendócrinas cada 100 enterocitos. En ciego se consideró epitelio superficial y criptal, mientras que en apéndice, epitelio superficial, criptas superficiales y criptas profundas. En epitelio superficial de ciego se hallaron 1,6 CEI/100 enterocitos en epitelio superficial y 3/100 en criptas. En G2 6 CEI/100 en epitelio superficial y 12/100 en criptas. La diferencia entre G1 y G2 fue estadísticamente significativa (p<0,05). En apéndice el epitelio superficial del G1 mostró 5,2/100 mientras que en G2 fue de 5.4/100 (no significativo). Las criptas superficiales evidenciaron 8,5/100 (G1) y 11.3/100 (G2) (p<0,05). En criptas profundas 4,9/100 (G1) y 8,5/100 (G2) (p<0,05). En los animales sensibilizados se detectó aumento significativo en la cantidad de células enteroendócrinas en ambos órganos. Dicho incremento podría atribuirse a un aumento de los gránulos intracitoplasmáticos o a la diferenciación de células generatrices a células APUD, como respuesta a la sensibilización.

Eosinophils in acute appendicitis: possible significance.

120 consecutive appendicectomies and 20 appendices from medicolegal autopsies were studied. The cases were grouped as. A: Acute appendicitis. B: Acute presentation, not diagnostic of acute appendicitis C: Elective appendicectomies D: Normal appendices from autopsies. Eosinophils and mast cells were counted in the muscularis, in Giemsa stained sections. The mean eosinophil and mast cell counts per mm2 were--A. 215.9; 26.5. B. 66.0; 32.1. C. 6.7; 25.8. D. 4.2; 19.6 respectively. Eosinophil count is significantly higher in A compared to others (p < 0.0001) and there was no range overlap with C and D. B is a heterogenous group with 37.5% having eosinophil counts in the range seen in A. Cases with mural eosinophil showed histological evidence of mast cell degranulation. Eosinophil infiltration of the muscularis is an early event universally seen in acute appendicitis. It is possible that the disease is triggered by Type I Hypersensitivity, and that infection is a later consequence.