Lymphocyte transformation test in diagnosis of nickel allergy. A comparison between the separation of peripheral blood lymphocytes on Ficoll-Paque, Percoll or by gravity sedimentation.

Different lymphocyte separation procedures, Percoll and Ficoll-Paque density sedimentation and gravity sedimentation, were tested in order to get optimal results in the lymphocyte transformation test in diagnosis of nickel allergy. Percoll at both investigated times, 3 and 6 days, gave the highest lymphocyte DNA synthesis response to nickel sulfate in nickel-allergic subjects and the most significant difference against control subjects. With all tested separation procedures there was an overlap between the patient and control group as regards the individual responses.