Use of the LTT in other pathogenic bacteria
In other persistent bacterial infections as well, serology reaches its diagnostic limits. The detection of antibodies (positive test result) only shows that at some point in the past the patient contracted such an infection, but provides no information about whether this infection is active at the time of testing. The lymphocyte transformation test detects whether the cellular immune system at the time of testing is still interacting with the pathogen, i.e., whether the infection is active at this point.
The difference in information between the detection of antigen-specific antibodies und T cells is that the T cells detected in the LTT have a limited lifespan compared with antibodies which are likely to persist lifelong.
Therefore, a positive LTT result indicates an interaction of the immune system with the pathogen during the last 4-6 weeks.
| Currently, the LTT is offered for the following pathogens: | |
|---|---|
| LTT Chlamydia trachomatis | LTT Helicobacter pylori |
| LTT Chlamydia pneumoniae | LTT Streptococcus |
| LTT Yersinia | LTT Staphylococcus |
| LTT Giardia lamblia (lamblia) | LTT Candida albicans |
Herpes viruses are special
The pathogen-specific LTT is of particular importance in obligate latent infections (e.g. CMV, EBV or other herpes viruses), because it is almost normal to have experienced an infection with these pathogens at some point in the past and consequently testing for antibodies will always yield positive results. With these obligate persistent pathogens, serology can never differentiate between latent and active infections. When interpreting the “viral“ LTT results, it must be kept in mind that a positive reaction up to a certain level is normal.
The immune system is typically interacting with herpes viruses every day. This distinguishes herpes viruses from Borrelia or other persisting facultative or obligate intracellular bacteria.
The strength of the reaction, however, provides information about the intensity (frequency and duration) of the interaction between the immune system and the pathogen.
A high stimulation index indicates an increased tendency towards reactivation. A noticeably high stimulation index is most significant when the 6 herpes viruses of relevance in humans are considered at the same time, as the differences can then be recognised.
For the following viruses, the LTT can be performed individually or in combination (see profile herpes viruses):
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