Igm, IgA and IgG antibodies against Bordetella pertussis were measured by enzyme-linked immunosorbent assay (ELISA) with an ultrasonicate of formalin-killed bacteria (a mixture of strains 1, 2 and 1, 2, 3) as antigen and disposable polystyrene 9-cuvette blocks as the solid phase. The specificity properties of the assay were assessed by an inhibition technique. Of the microbes tested, only B. parapertussis was able to cause a significant inhibition. In addition, IgM and IgA antibodies against B. pertussis were only found in some sporadic cases of respiratory infections caused by other microbes. Sera, nasal swabs and cough plates were received from 198 patients with suspected whooping-cough. ELISA determinations were mostly made from only one serum sample of each patient. Paired sera were studied only from the culture-positive infants under 3 months of age. The number of positive cultures was highest in group under 3 months of age (41%), where the frequency of positive ELISA was lowest (20%). The use of paired sera strikingly increased the number of ELISA-positive individuals in this youngest patient group. In later life, the relationship between these tests changed: isolation was positive in only about 10% of the patients, whereas 29-64% yielded positive titres in ELISA. This study shows that pertussis ELISA is a valuable aid in the rapid diagnosis of pertussis, particularly of the atypical forms of the disease which mostly are culture-negative.
We evaluated the performance of new enzyme immunoassay (EIA) kits (Pyloriset; Orion Corporation, Orion Diagnostica, Espoo, Finland) for the detection of immunoglobulin G (IgG) and IgA antibodies to Helicobacter pylori in serum. Serum samples from 195 patients with upper abdominal complaints were collected. Biopsy specimens of the gastric mucosae were taken for histological analysis and bacterial culture. The sensitivity, specificity, positive and negative predictive values, and efficacy of the Pyloriset EIA-G in detecting IgG antibodies to H. pylori were 92, 84, 88, 90, and 89%, respectively, when compared with those of the reference methods used. The corresponding data for detection of IgA antibodies were 80, 89, 89, 79, and 84%, respectively. The overall prevalence of defined H. pyloni positivity was 54%. Moreover, the antibody tests showed a very good correlation with the biopsy findings. IgG antibodies were found in 93% of sera from patients with documented gastritis and H. pylori positivity, whereas only 4% of the sera from patients with documented gastritis and H. pylori-negative patients was positive. The results obtained for IgA antibodies were 81 and 6%, respectively. We conclude that the Pyloriset EIA-G, the test for IgG antibodies, is a good and reliable test for the detection of antibodies to H. pylori and as an indication of H. pyloni infection. The determination of IgA antibodies may be used as a test that complements the IgG antibody assay.
Helicobacter pylori infection is widespread among the Siberian populations with some trend in its prevalence to decrease northward. In Siberia age-specific prevalence rates of H. pylori infection are similar to those usual for developing countries.
The prevalence of seropositivity among adolescents in Russia is higher than in developed countries. The infection is associated with lower socioeconomic status.
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