Peripheral blood lymphocyte subpopulations in patients with primary proliferative and secondary polycythaemia.

Peripheral blood lymphocyte subpopulations were measured in 18 patients with primary proliferative polycythaemia and 13 patients with secondary polycythaemia. A decrease in numbers of suppressor T lymphocytes and an increase in the helper:suppressor T lymphocyte ratio was found in those with primary polycythaemia compared with normal subjects and patients with secondary polycythaemia. If other causes of an increased helper:suppressor ratio are excluded this variable may be useful in confirming the myeloproliferative nature of patients with erythrocytosis.