Prolonged duodenal mucosal lymphocyte alterations in patients with and without post infectious functional gastrointestinal disorders after Giardia infection.

Objective: Persisting low grade inflammation is suggested to play a role in post-infectious functional gastrointestinal disorders (PI-FGID). The present study examined alterations in duodenal mucosal lymphocytes during and after Giardia gastroenteritis in patients who did, or did not, develop PI-FGID.

Design: Duodenal mucosal intraepithelial lymphocytes (IELs) and lamina propria CD3, CD4, CD8 and CD20 lymphocytes were quantified in 28 chronic giardiasis (CG) patients, 66 patients with persistent abdominal symptoms after acute Giardia infection (PI-FGID), 19 recovered controls (RC) and 16 healthy volunteers (HC). Associations with illness duration, abdominal symptoms and histology grade were assessed.

Results: Duodenal CD4 IEL were significantly elevated in CG, then decreased, followed by an upwards trend after one year in both the PI-FGID and RC groups. Duodenal lamina propria crypt CD4 T cells were decreased in CG, and stayed low for about 14 months before normalizing in both PI-FGID and RC groups. Lamina propria CD20 cells were persistently elevated in all three Giardia exposed groups. Biopsies with microscopic inflammation showed increased lamina propria CD20 levels.

Conclusions: Duodenal mucosa lymphocyte alterations were prolonged after Giardia infection, but similar in patients who developed PI-FGID and recovered asymptomatic controls.