Theophylline-resistant and theophylline-sensitive "early" and "late" E rosette-forming cells in young and aged humans.

The percentage of cells with high-affinity sheep red blood cell (SRBC) receptors, "active" or "early" rosette-forming cells, (ARFC) in theophylline-resistant peripheral blood T lymphocytes achieve higher values in aged subjects and, in particular, in the group with clinically manifested atherosclerosis. A diminished OKT-4/OKT-8 ratio in theophylline-resistant ARFC was noticed in this group. On the contrary, the proportion of the theophylline-resistant cells with low-affinity receptors, cold or late rosette-forming cells (CRFC) attained lower values in aged subjects than in young subjects. No statistical difference in the proportion of theophylline-sensitive T cells was evident between old and young people, both in ARFC and CRFC fractions. This is indicative of the elevation of activated (or less differentiated) cytotoxic T cells in the peripheral blood of aged subjects with clinically manifested atherosclerosis. The clinical aspect is still to be considered.