Immunoblot for the detection of IgG or IgA antibodies against Chlamydia trachomatis in serum

This test is to be used for the proof of chronic inflammations caused by Chlamydia trachomatis such as infertility and reactive arthritis.

 SUMMARY AND EXPLANATION OF THE TEST

Proof for:

Only with the aid of the C. trachomatis westernblot can references to chronic  inflammations that lead to the illnesses mentioned above be recognized. In cases of Chlamydia-induced salpingitis, which can lead to infertility, and in which an antigen is often not detectable in the genital region, serological tests can give crucial information for the diagnosis. The detection of IgG and IgA is an important indication of Chlamydia-induced reactive arthritis.

The test enables a clear differentiation to Chlamydia pneumoniae. Antibodies against heat shock proteins are a clear indication of infertility.

Chlamydia are obligatorily intracellularly growing bacteria. Three species are known:

In the progress of the development cycle of Chlamydia, two characteristic cellular forms appears:

All Chlamydia possess as a common group antigen a lipopolysaccharide.

Species specific determinants are found in the case of C. trachomatis and C. psittaci on the particular „Major Outer Membrane Proteins“ (MOMPS), in the case of C. pneumoniae on other surface proteins.

The strains of Chlamydia trachomatis can be divided into three biovars:

Trachome and Lymphogranuloma venereum are exclusively human pathogenic and can be classed into 15 particular characteristic signs of disease: 

Especially men with non-gonorrhoeal urethritis develop in about 1% of all cases reactive arthritis in some joints, whereby there is often an association with HLA-B27.

Chlamydia-induced reactive arthritis appears after urogenital infections with the serovars D – K, it is numbered to the post-urethritic reactive arthritis. Also after infections with the serovars L1-L3 sporadic reactive arthritis have been described.

The diagnosis is made by the detection of the pathogen (detection of the inclusion bodies in direct preparation), by antigen or antibody detection in IFT or ELISA and in the immunoblot and the PCR. Especially in cases of longer existing urogenital infections and the development of reactive arthritis an antigen is sometimes no longer detectable and a diagnosis is only possible by serological methods.

EVALUATION AND INTERPRETATION OF THE RESUTS

The following bands are characterized:

LPS (different molecular weights) characteristic of Chlamydia trachomatis and pneumoniae.

Heat shock proteins (HSP) 60 kD, 70 kD are not specific, but important for the recognition of chronic stages.

Chlamydia Trachomatis-specific bands:

Specificity:

There is often a cross reaction between C. trachomatis and C. pneumoniae. However, antibodies against C. pneumoniae appear faintly in the immunoblot for C. trachomatis (mostly by a faint reaction of the MOMP 1) so that one can neglect a singular faint MOMP 1 band. It is probably caused by a linkage of lower affine antibodies.

MOMP 1‘ only appears in correlation with MOMP 1 (very seldom singular).

The test kit is constructed in such a way that no acute primary infections are detectable. It is especially intended for the proof of chronic diseases (e. g. reactive arthritis, infertility and inflammations of the pelvis).

Interpretation:

IgG:

Possibly positive state – 1 specific band with a significant marked MOMP 1 band – 40 kD (Scanner intensity: 35 %).

Positive state  - 2 specific bands with 1 marked MOMP 1 band – 40 kD.

IgA:

Possibly positive state – 1 alone MOMP 1  – 40 kD with a significant marked (Scanner intensity > 35 %).

Positive state  - 1 MOMP 1 – 40 kD and 1 specific band with significant marked

Further aid for interpretation:

Significant for chronic diseases is the detection of antibodies against heat shock proteins.

Antibodies against HSP 60 are associated with infertility and primary abortion.

Reactive arthritis induced by C. trachomatis are often associated with the occurrence of a specific band 57 kD. Further the occurrence of IgA antibodies against C. trachomatis can be a reference to Chlamydia induced reactive arthritis.

Examples of interpretation

Long passed infection, remaining titer - IgA: negative and IgG: MOMP 1 and HSP 60, 70 positive

Normally concluded infection - IgA: negative and IgG: MOMP 1 and several specific bands positive

Chronic inflammable infection, Reference to reactive arthritis or inflammation of fallopian tube (salpingitis) - IgA: positive MOMP 1 + 1 specific band * HSP +    and   IgG: positive MOMP 1 + HSP +

Acute infection or re-infection -  IgA: MOMP 1 + several bands +   and    IgG: several bands +