T cell subpopulations in CLL: methods of T cell enrichment artificially alter proportions of OKT4 and OKT8 positive cells.

There is growing speculation about the meaning of reported imbalances in subpopulations of T lymphocytes in patients with chronic lymphocytic leukaemia (CLL). This study compared two techniques for producing T cell enriched subpopulations from both patients with CLL and normal individuals and the effects of these techniques on relative proportions of OKT4 and OKT8 positive cells. A sheep red cell rosetting technique resulted in significantly larger OKT8 and smaller OKT4 positive populations than did nylon wool column elution. Similar results were obtained in normal individuals. The nylon wool column elution technique produced less distortion of unfractionated OKT4/OKT8 ratios in normals than did the rosetting technique. Studies of T lymphocyte subpopulations should be interpreted with great caution as the methods used to study them can influence the results.