[Enteropathogenic mechanisms involved in giardiasis in children (author's transl)].

23 patients with gastroenteritis and 9 with severe malabsorption syndrome related to giardiasis were investigated in a semi-prospective fashion as follows: (1) conjugated bile acid levels measured in duodenal aspirate (thin layer chromatography) in 6 patients with steatorrhea. (2) intraepithelial lymphocytes count (results expressed as the number of intraepithelial lymphocytes per 100 epithelial cells) in small intestinal biopsies from the 32 patients, 11 of which had immunoglobulin deficiency (9 IgA deficiency). The results indicate that there is no decrease in the percentage of conjugated bile acids (mean percentage 90%; normal = 80); a significantly increased percentage of intra-epithelial lymphocytes is documented in giardiasis (11.1% +/- 6.7), versus 2.3% +/- 0.5 in acute gastroenteritis (9 patients) and 6.3 +/- 0.5 in chronic diarrheas (6 patients) (p less than 0,001). This percentage, however, is significantly lower than in untreated coeliac sprue (23 patients) (12.17 +/- 11.6) (p less than 0,01). Conversely a high intraepithelial lymphocyte count does not correlate with the degree of intestinal villous atrophy (3 patients had severe and 6 partial villous atrophy) (r = 0.170). IgA deficiency should be suspected in patients with giardiasis presenting with intestinal villous atrophy (5 patients). Steatorrhea in our patients does not appear related to bile acid deconjugation. To explain enterotoxicity in giardiasis, more than a direct effect of the ventral disk of the parasite on intestinal mucosa, one should incriminate the host immune cell mediated response as shown by lymphocytic infiltration of the epithelium on small bowel biopsies.