Immunoblot for the detection of IgG/IgM/IgA-antibodies against Chlamydia Pneumonia in serum

SUMMARY AND EXPLANATION OF THE TEST

In some circumstances sensible to differentiate between a reaction of the antibodies against C. pneumoniae and C. trachomatis in women, because a seroprevalence against this pathogen can amount up to 50 %, but only C. trachomatis can be   dangerous during the pregnancy.

The same applies for both sexes in case of a Chlamydia-induced arthritis.

The Chlamydia pneumoniae immunoblot enables an exact differentiation to Chlamydia trachomatis.

The IgA antibodies determined in the blot suggest chronic Chlamydia pneumonia.

Besides that, a relation between the IgA antibody pattern and the risk of a cardiac infarct is discussed.

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

Two characteristic forms of cells appear during a development cycle:

All Chlamydia have as a common group antigen a lipopolysaccharide.

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

C. pneumoniae is only human pathogenic. The infection occurs by droplet infection. The seroprevalence in adults lies between 40 % and 70 %. C. pneumoniae belongs to the most frequent pathogens of pneumonia.

Reactive arthritis induced by C. pneumoniae has occasionally been described, but as a rule arthritis, induced by Chlamydia can be explained with the appearance of the serovars D-K of C. trachomatis. 

ANALYSIS OF BAND PATTERN AND INTERPRETATION OF THE RESULTS

 The following bands are characterized:

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

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

Chlamydia Pneumoniae specific bands

Specificity:

The cross reaction between antibodies against C. trachomatis and C. pneumoniae appear very often (antibodies against C. trachomatis lead in the C. pneumoniae often to a severe reaction), especially in the lower molecular range.

Nevertheless, the specific bands mentioned above appear only in cases of Chlamydia pneumoniae.

Notes:

The contamination of the population with C. pneumoniae is very high.

Therefore a reaction of persisting antibodies (IgG) is likely (LPS, weak MOMP or other not yet characterized bands, the significance of which is not yet clear).

Interpretation:

IgG:

If 2 specific bands are marked, it is a possibly positive IgG state

If 3 or more specific bands are marked, it is a positive IgG state.

IgM/IgA:

If at least 2 specific bands are marked, it is a positive state.

Further aid for interpretation:

IgA antibodies against C. pneumoniae appear in cases of chronic pneumonia.

According to literature, antibodies against antigens of 40 kD, 54 kD and 60 kD refer to a higher risk of arteriosclerosis.

Examples of interpretation

IgA/IgG several bands – 3 or more - Chronic active infection or reinfection

IgA few specific bands, e. g. 98 kD, 54 kD, 48 kD – Possible reference to chronic mild infection or reference to arteriosclerosis.

IgG few specific bands, e. g. HSP , 98 kD, 40 kD, 54 kD - Possible referance to chronic mild infection or reference to arteriosclerosis