IVPT: in vitro patch tests

The page has been noted! A report of the National Institute for Public Health and the Environment in Bilthoven (the Netherlands), commissioned by the Dutch Ministry of Health, Welfare and Sports and the Food and Consumer Product Safety Authority has indicated this website as the first source of information on the relevant literature (compare: Ezendam J, van Loveren H. "Detection of sensitization to low molecular weight chemicals. Inventory and evaluation of ex vivo methods". RIVM Letter Report 340300002, Bilthoven 2009, page 6; → download the report).

How far are we from reliable laboratory diagnosis of contact allergy?

At present, the mainstay of contact allergy diagnosis is the epicutaneous skin test, referred to as patch test (→ read more about patch test). Despite all efforts, there is still no laboratory test that could be used in routine diagnosis of contact allergy. Possible reasons are: high cost, technical difficulties, unsatisfactory sensitivity and specificity, and lack of validation. Yet another obstacle is the scarce and incomplete information regarding laboratory tests that have already been evaluated by various researchers. Therefore, this website has been launched to collect and collate available data on laboratory techniques used for in vitro detection of contact allergy, and to make this information available to all interested. We continuosly review published literature describing effectiveness of laboratory techniques in the detection of contact allergy, with particular attention to 28 haptens/mixes included in the European Baseline Series (EBS), which is the first line diagnosis of contact allergy in Europe.

Throughout history, the following laboratory tests (also referred to as in vitro or ex vivo tests) were used for the detection of specific response in contact allergy: migration inhibition test (MIF), lymphocyte blastic transformation test (LBTT), lymphocyte proliferation test (LPT), analysis of secreted cytokines and chemokines (ELISA, ELISPOT), cell markers (flow cytometry) and gene expression (PCR). One or more in vitro techniques were successfully used in the detection of contact allergy to 8 substances from the EBS: nickel, cobalt, chromium, methyl(chloro)isothiasolinone, fragrances, thiurams, 4-phenylenediamine, sesquiterpene lactones. Beyond the EBS, in vitro assays were applied with some success in the detection of hypersensitivity to gold, palladium, and methacrylates. Sensitivity of these tests ranged from 38-79%, and specificity from 81-93%.

Table: An overview of laboratory studies applied in the detection of contact allergy

Until now, in vitro tests have been successfully applied in only 8 of 28 substances from the European Baseline Series, however, even for these tests validation is still missing. Concerted efforts of all researchers active in this field are crucial for identification of optimal methods and protocols, leading to a validated laboratory test that would be as good as patch test. Discussion with colleagues indicate that journals refuse to publish reports with negative results, which leads to the risk of repeating expensive studies of ineffective assays by other investigators. In order to overcome this serious publication bias, this new Internet site www.ivpt.info was launched, where information from both published and unpublished studies with additional comments can be posted for the benefit of scientific community.

Important: If you are aware of a paper relevant to this topic that has not been included into this compilation, please let me know - you will find the contact email here. I will be more than happy to include previously unpublished negative results into this analysis - these are as important as "positive" results, yet we all know how difficult it is to get them published. In such case, please send me a description of your study for posting on this webpage in the form following rules for a standard manuscript with the aims, methods, results and conclusions (the introduction and discussion are welcome, yet not obligatory - a short comment summing up your experiments will suffice). The copyright for such manuscript shall remain with the authors.

Copyright © Radoslaw Spiewak
Document created: 4 June 2009, last updated: 21 September 2013.
This page is part of www.ivpt.info website.