Detection of IgA antibodies against Yersinia enterocolitica by Western Blot is used to validate the results of other serological methods to document yersinosis, reactive arthritis, and other complications of Yersinia infection. Western blot is a valuable tool for the detection of Yersinia enterocolitica antibodies, offering high specificity and detailed information about the immune response against the pathogen, having the following advantages:
- Sensitivity and Specificity: Western blotting is highly sensitive and specific, making it suitable for confirming serological test results. Compared to other serological tests, it minimizes cross-reactivity.
- Confirmation of Serological Tests: It is often used to confirm positive results from ELISA or other serological tests for Yersinia enterocolitica antibodies.
- Detailed Antigenic Profile: Western blotting can provide detailed information about which Yersinia antigens the patient's immune system recognizes.
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The genus Yersinia consists of two Gram-negative coccobacillus species known to cause enteric infections in humans: Yersinia enterocolitica and Yersinia pseudotuberculosis. Infections with Y. enterocolitica are transmitted primarily to humans through soil, water, animals, and food. Infections with Y. enterocolitica most often occur in young children. The disease manifests in the gastrointestinal tract, causing symptoms of diarrhea, loose, watery, or bloody stools, abdominal pain, and fever. Y. pseudotuberculosis is less pathogenic and causes a zoonotic disease with symptoms similar to those caused by Y. enterocolitica. Infections with Y. enterocolitica and Y. pseudotuberculosis can be asymptomatic, mild, or severe and resolve within a few weeks, with or without antibiotics, depending on the severity. Complications can occur, however, with the development of an inflammatory arthritis known as reactive arthritis, which can manifest 1 to 4 weeks postinfection. There is an increased risk of developing reactive arthritis if the individual is positive for the major histocompatibility complex HLA-B27 allele.
The incidence of reactive arthritis following Y. enterocolitica infection is very high among adults in Scandinavia, estimated at 10 to 30%. The incidence is much lower in most other countries. The most affected joints are the knees and ankles, but other joints, such as the toe, finger, and wrist, can be involved. In most cases, two to four joints become involved sequentially and asymmetrically over a few days to 2 weeks. Monoarticular arthritis occurs less commonly. In two-thirds of cases, the acute arthritis persists for 1 to 4 months. Chronic joint disease or ankylosing spondylitis occurs rarely. Subsequent complications of Y. enterocolitica infections that occur less often include reactive uveitis, iritis, conjunctivitis, glomerulonephritis, and urethritis. Reiter's syndrome (arthritis, conjunctivitis, and urethritis) is seen in only 5 to 10% of patients with yersinia-induced arthritis.
Serologic tests can be used to support a diagnosis of yersiniosis. With yersiniosis, antibody levels rise within the first week of illness, peak in the second week, and then return to normal within 3 to 6 months. Antibodies may also remain detectable for several years. Isolating a pathogenic Yersinia strain from feces is the most specific test for diagnosing yersiniosis. However, culture is not very sensitive for reactive arthritis, and serologic tests for Yersinia can be helpful diagnostically in cases with a high index of clinical suspicion.
Antibodies develop against the Yersinia outer membrane proteins (Yops) and usually persist at high levels for extended periods in cases with associated arthritis and chronic enteritis. It has been reported that the assays used to detect antibodies against Yops are more sensitive and specific than stool culture and other serologic methods for diagnosing Yersinia-associated complications.
Yersinia has been reported to cross-react with other bacterial species, such as Borrellia burgdorferi, Rickettsia rickettsii, and Brucella spp. Additionally, cross-reactivity between Yersinia and thyroid-stimulating immunoglobulin (TSI) in patients with Graves ' disease has been shown.
For all these reasons, testing and confirming yersinosis by Western Blot is an excellent laboratory tool.
