Antibodies IgA, IgM, IgG to CHLAMYDIA TRACHOMATIS in serum
Diagnostic AT titer for Chlamydia trachomatis in the blood: for IgM - 1: 200 and above, for IgG - 1:10 and above.
During acute Chlamydia infection and soon after it there is an increase in the titre of ATA IgA, IgM and IgG to Chlamydia trachomatis in the blood. Infected Chlamydia trachomatis organism synthesizes AT, however these AT have a weak protective effect: usually pathogens persist even in the presence of high AT titers. Early intensive treatment may inhibit AT synthesis. Due to the relatively large "antigenic mass" of chlamydia in genital infections, serum AT IgG is detected quite often and in high tiers. So, in children with chlamydial pneumonia they can be very high: 1: 1600-1: 3200.
ATM IgM is detected in the acute period of infection( already 5 days after its onset).The peak of Ig Ig occurs at 1-2 weeks, then a gradual decrease in their titer occurs( as a rule, they disappear after 2-3 months even without treatment).AT class IgM directed against the lipopolysaccharide and the main protein of the outer membrane of chlamydia. The presence of AT IgM indicates the activity of chlamydia. The IgM antibodies do not penetrate the placenta, they are synthesized by the fetus and belong to the newborns' own AT.Their presence indicates infection( including intrauterine) and indicates an active process. The titer of IgM-AT can increase with reactivation, reinfection or superinfection. The period of their half-life is 5 days.
АТ class IgA are synthesized to the main protein of the outer membrane and a protein with a molecular weight of 60,000-62,000 chlamydia. They are detected in the blood serum 10-14 days after the onset of the disease, their titer usually decreases by 2-4 months as a result of successful treatment. When reinfection, the titer of ATA IgA again increases. If after the course of treatment the ATA titer does not decrease, it indicates a chronic or persistent form of infection. The detection of a high titer of ATA class IgA often indicates a pronounced autoimmune process in the patient, most often seen in patients with Reiter's syndrome. In such patients, the presence of ATA class IgA suggests a severe course of the disease.
AT-class IgG appear 15-20 days after the onset of the disease and can persist for many years. Reinfection is accompanied by an increase in the existing titre of AT class IgG.The determination of the AT titer for chlamydia in the blood should be carried out in dynamics, the evaluation of the results of studies based on a single study is unreliable. AT class IgG penetrate the placenta and form anti-infectious immunity in newborns. High IgG-AT titers protect the fetus from infection, as well as women, from the appearance of salpingitis after abortion;in addition, provide a short-term protection
that( up to 6 months) from re-infection with chlamydia. The half-life of IgG-AT is 23 days.
To establish the diagnosis it is necessary to simultaneously determine the AT classes of IgA and IgG, with an unclear result of IgA - to further investigate the Ig IgM.
Newborns and their mothers are examined on the 1-3th day after birth, in case of a negative result in the presence of a clinical picture of the disease - again on the 5th-7th and 10th-14th day. The presence of ATM class IgM in a second study, indicates a congenital infection( maternal IgA class IgM through the placenta does not penetrate).The absence of antichlamydial antibodies in newborns does not mean the absence of chlamydia infection.
Determination of the AT titer for Chlamydia trachomatis in the blood is an auxiliary test for the diagnosis of chlamydia, because of low immunogenicity in 50% of patients with chlamydia, AT is not detected.
The determination of ATA classes of IgA, IgM and IgG for Chlamydia trachomatis in the blood is used to diagnose chlamydia infection in the following diseases:
■ urethritis, prostatitis, cervicitis, adnexitis;
■ pneumonia, inflammatory diseases of the lungs;
■ Reiter's disease, Behcet's syndrome, infectious arthropathy.
Express diagnosis of urogenital chlamydiosis
Chlamydia trachomatis in the material from the genito-urinary organs is normal.
The method is based on the detection of Arg Chlamydia trachomatis in scrapings from the urethra, cervical canal and conjunctiva by ELISA with a visual evaluation of the result( sensitivity is over 79%, specificity is more than 95%).This method is based on the presence in chlamydia of the rhodospecific lipopolysaccharide Ar. It allows rapid screening of the pathogen, but the final diagnosis is established using fluorescent AT or PCR.The results of the study are expressed in the form of a positive or negative answer. To obtain satisfactory results of the study, it is necessary to follow certain rules: the material( scraping) should be correctly taken and delivered to the laboratory in a timely manner( within 2 hours).
Express diagnosis of urogenital chlamydiosis is used for urethritis, prostatitis, cervicitis, adnexitis.