Diagnostic Testing for Nickel Allergic Hypersensitivity: Patch Testing versus Lymphocyte Transformation Test

Abstract

This review evaluates the lymphocyte transformation test (LTT) as an in vitro alternative to the traditional patch testing. Patch test results require knowledge, practice and experience for correct biological and clinical interpretation, and in spite of long-term use, the method is fraught with technical and interpretative limitations. Nickel in particular is an allergen eliciting false-positive reactions in patch testing due to the irritancy of test materials; it is sometimes difficult to distinguish an irritant reaction from a true allergic response, and patients may need to be tested more than once. Also false-negative reactions can occur due to varying sensitivity of the patient. It therefore appears reasonable to search for a more objective, in vitro alternative; the LTT appears one procedure which gives relatively reliable results. Still, at this point this method can only be used in association with patch testing, and it has often given results inconsistent with the patch test.