Correspondence (letter to the editor): Comprehensive Literature

I cannot share the view that immunological tests have no relevance in the differential diagnosis of environmental-medical patients. Diagnostic tests to demonstrate allergic reactions to environmental agents that rely on the patient's history, do, however, prevent subsequent doctor hopping and save substantial costs.

The authors note that the lymphocyte transformation test (LTT) is currently not informative enough. They cite as a supporting reference a statement from the Robert-Koch-Institute. However, if methodologically carefully applied and validated within the laboratory, the LTT confirms type IV sensitization. For many allergens, more comprehensive literature is available than for the epicutaneous test. Professor Merck of RWTH Aachen University emphasized even in 2004 that in vitro tests are an important alternative when testing for toxic and sensitizing substances (1). The LTT for pharmacological substances was included in the guideline for the diagnosis of sensitization to medical drugs issued by the German Society for Allergology and Clinical Immunology, after many positive study reports had been published (2). All the RKI did was state, correctly, that the LTT as a laboratory test cannot show the current clinical manifestation of the sensitization, but in this does not differ from the IgE-RAST or skin tests. A diagnosis of allergy is for the doctor alone to make, aided by sensitization tests. I do not understand why the LTT is recommended to confirm sensitization to substances if they are ingredients of a medical drug but not if contact with the substance has occurred in a different context. And how come the tests conducted in the same specialized laboratory can prove sensitization if they are applied by allergologists, but cannot do so when an environmental medical specialist applies them? Patients consult environmental doctors with the same idea: that their complaint is comprehensively considered and dealt with.