Safety assessment
is an essential component of the regulatory acceptance
of industrial chemicals. Previously, we have developed a model to
predict the skin sensitization potential of chemicals for two assays,
the human patch test and murine local lymph node assay, and implemented
this model in a web portal. Here, we report on the substantially revised
and expanded freely available web tool, Pred-Skin version 3.0. This
up-to-date version of Pred-Skin incorporates multiple quantitative
structure–activity relationship (QSAR) models developed with in vitro, in chemico, and mice and human in vivo data, integrated into a consensus naïve Bayes
model that predicts human effects. Individual QSAR models were generated
using skin sensitization data derived from human repeat insult patch
tests, human maximization tests, and mouse local lymph node assays.
In addition, data for three validated alternative methods, the direct
peptide reactivity assay, KeratinoSens, and the human cell line activation
test, were employed as well. Models were developed using open-source
tools and rigorously validated according to the best practices of
QSAR modeling. Predictions obtained from these models were then used
to build a naïve Bayes model for predicting human skin sensitization
with the following external prediction accuracy: correct classification
rate (89%), sensitivity (94%), positive predicted value (91%), specificity
(84%), and negative predicted value (89%). As an additional assessment
of model performance, we identified 11 cosmetic ingredients known
to cause skin sensitization but were not included in our training
set, and nine of them were accurately predicted as sensitizers by
our models. Pred-Skin can be used as a reliable alternative to animal
tests for predicting human skin sensitization.