Studies on the specificity of CML. Report from a CML-workshop.

In a collaboratory study involving eight different laboratories 30 human, mixed lymphocyte culture educated cytotoxic lymphocytes (CTLs) were identified yielding reproducible cytolysis on allogenic lymphocyte target cells without detectable HLA-A, B (and C) antigenic sharing between stimulator and target cells. These CTLs were collected in one laboratory (Aarhus) and tested in parallel against a population sample of 100 unrelated, healthy Danes. The testing was only performed once and 11 CTLs did not discriminate in the population, probably due to transportation damage. On the basis of pairwise comparisons between 19 CTLs, three tentative CML-defined specificities could be recognized. These three groups may have defined monospecific traits of allelic genetic origin as judged by a mutually negative, albeit not significant, correlation and a fit to Hardy-Weinberg equilibrium. The concept of determinants other than the serologically defined HLA antigens recognized by some CTLs can thus still be maintained as can the approach to CML typing tested in this workshop.