Detection of antibodies against Helicobacter pylori

Anti-Helicobacter antibodies in serum can be detected by various immunological and serological techniques such as immunoblotting, immunofluorescence, hemagglutination, complement fixation, latex agglutination test and others. However the most common method is indisputably ELISA – simple, fast, cheap and reliable technique. Specificity and sensitivity of the method depend on the applied antigene – from the whole cells, through the ultrasound sonicator, glycine extract to protein purification. In the year 1989 was isolated the HM-CAP, high molecular weight cell-associated protein, which sensitivity and specificity reach 95 %.

Serological evidence of anti-Helicobacter pylori antibodies is clinically significant mainly for long term observation in treatment and monitoring of the succes of the Helicobacter pylori eradication. Decrease of the IgG to < 50 % after 6 months of the treatment evinces the specificity 95 % and the sensitivity 97 %. Indication includes screening in high-risk patients, for example in patients with kidney transplant, when helicobacter infection increases the risk of the peptic ulcer and bleeding.

Anti-Helicobacter antibodies can be also detected in saliva and urine samples with help of the imunological methods. There are many rapid tests which detect anti-Helicobacter antibodies in blood samples after the capillary blood sampling during a couple of minutes with help of the immunoaffinity chromatography. Sensitivity and specificity of these tests are relatively low – from 70 up to 85 %.

One of the methods of anti-Helicobacter antibodies serological evidence is detection of the antigenes cagA, vacA and iceA, which are present in Helicobacter pylori phyla with higher pathogenicity. These antigenes are detected with help of classic ELISA tests on the microtiter plates or PCR techniques. The evidence of Helicobacter pylori and its phyla by the PCR methods is now in clinical research and is not applied in routine investigation. Diagnostic value of anti-Helicobacter pylori antibodies detection is permanently a subject of research, not convenient for the screening programs.