In vitro testing of contact sensitivity.

A new in vitro technique for the testing for contact sensitivity is described. The method is based upon the fact that in response to immunological stimuli, keratinocytes can start to synthesize and express class II histocompatibility antigens. Nickel sulphate (NiSO4) stimulated lymphocytes from nickel-sensitive persons, and the supernatant of these cells thus induced expression of HLA-DR on keratinocytes when co-cultured with autologous normal skin biopsies. This was in contrast to what was the case in healthy controls.