Further studies on the lymphocyte transformation test in diagnosis of nickel allergy. Effect of fractionation of lymphocytes into different subpopulations on the basis of density.

Peripheral blood lymphocytes from nickel-allergic and control subjects were fractionated into different subpopulations on the basis of density on Percoll, in an attempt to improve the lymphocyte transformation test in diagnosis of nickel allergy. Significant differences were obtained between the subject groups with cells recovered at densities of 1.046 and 1.058 g/ml, however, a higher significant difference was found in unseparated cells. The results still support the relative value of the transformation test as a diagnostic tool in nickel allergy. In addition, an unspecific mitogenic effect of nickel on lymphocytes is emphasized.