Limited information is available on the systemic immunoglobulin response in patients infected with the emerging pathogen Campylobacter concisus. The aim of the present study was to detect anti-C. concisus antibodies in serum of 88 patients with C. concisus gastroenteritis. Specific IgG antibodies to C. concisus were measured in serum using an in-house enzyme-linked immunosorbent assay, and pooled donor serum was used as a control. The mean optical density was 0.135 (SEM: 0.020) for the 88 adult patients and 0.100 (SEM: 0.011) in controls. When using an optical density value equal to the mean +3 SEM for the control serum, 22 (25%) C. concisus-positive patients had increased IgG antibodies. patients with high IgG levels more often reported headache, and they had a trend toward more mucus in stools, whereas IgG levels were unrelated to age, duration of diarrhea, number of stools per day, and weight loss.
