[Bowel parasites and faecal eosinophilia]. / Les parasites intestinaux et l'éosinophilie fécale.

The staining of polynuclear eosinophils (PE) in the stools, easily performed and adapted from the technique of WHEATLEY, presents important advantages over the May-Grünwald-Giemsa: less colouring of the bacteria, no dissolution of the lipids, less importance of the stools pH. The stools samples must show mucus or have a soft, loose or liquid consistency: the polynuclear eosinophils are preserved in stools for 1 year and more, which allows if necessary to postpone for a few days the direct examination. The PE are found among patients having a helminthiasis or an intestinal coccidiosis in half of the cases, whereas they are not found in other intestinal protozoosis. They are also found among patients having an intestinal allergy. Faecal eosinophilia reveals an intestinal eosinophilia of the tissue and is influenced by several factors in particular: importance, duration, repetition of the infestation. It allows the observation of many elements related to the mechanism of eosinophilia, not to be found in blood eosinophilia, in particular the release of the eosinophil granule, the formation of Charcot-Leyden crystals and the presence of lipid bodies similar to those of stearrhoea.

The demonstration, staining and prevalences, in pathological and non-pathological specimens, of eosinophils in faeces.

Although eosinophils are occasionally reported in mucus there has been no description of them in faecal samples. Attempts were made to demonstrate eosinophils in stool samples using several different staining techniques. Use of an acid dye, Acid Red 29, was found to be the simplest and most direct method of revealing eosinophils, producing very characteristic, orange-brown, sometimes red, staining of the intracellular granules that contain eosinophil cationic protein. In stool samples held at room temperature, without preservative, eosinophils remained demonstrable for a mean of 15 days and occasionally for a year. The peroxidase in the eosinophilic granules may help to preserve the cells. Eosinophils were found in 32 (14%) of 223 stool samples from patients with intestinal disease (including the results of several parasitic infections) but in none of 72 samples from apparently healthy hospital personnel (P<0.001). Eosinophils were never found in formed stool specimens that did not contain mucus. The demonstration of eosinophils in faecal samples may be a useful indicator of infection with intestinal helminths or of drug- or food-related digestive allergies.