Cloning of T-lymphocytes in systemic lupus erythematosus.
Colony-forming T-lymphocytes were studied in the blood of twenty-two patients with systemic lupus erythematosus (SLE) by the technique of plating phytohaemagglutinin (PHA) stimulated lymphocytes in soft agar. The mean count of T-lymphocyte colonies in SLE of 70+/-64 (1 s.d.)/mm3 of blood was considerably less than the count of 218+/-102/mm3 for healthy young adults and of 139+/-99/mm3 for aged persons. In SLE, counts of T-lymphocyte colonies correlated with low counts of T-lymphocytes in blood and with other indices of T-lymphocyte impairment. The data point to derangement of factors which influence the capacity of T-lymphocytes to proliferate, but it cannot be stated to what degree this is a cause and/or result of the autoimmune disease process associated with SLE. Cloning of peripheral blood T-cells could help determine whether the essential defect in SLE is in the T-lymphocyte or one of its sub-sets, or in factors produced by adherent cells which are essential for growth in vitro of T-lymphocyte colonies.