ALTERATION OF PERIPHERAL-BLOOD LYMPHOCYTE SUBSETS IN ESSENTIAL-HYPERTENSION

OBJECTIVE: To assess lymphocytic subpopulation by labelled monoclonal antibody technique in a small group of patients with untreated essenti al hypertension (EH) and to detect any alteration with control of bloo d pressure. DESIGN: Prospective study with phenotypic estimation of ly mphocytes at presentation and a minimum of two weeks after the control of blood pressure. SETTING: Referral, tertiary care hospital. PATIENT S: Group 1, normotensive controls (n=10); group 2, mild to moderate es sential hypertension (n=10); group 3, severe mild to moderate essentia l hypertension (n-10). All the secondary causes of hypertension were r uled out by a thorough history, physical examination and appropriate r adiological and biochemical investigations. TESTS: Venous blood sample s, taken at entry and a minimum of two weeks after control of blood pr essure, were analysed by alkaline phosphatase antialkaline phosphatase (APAAP) antibody technique for CD4, CD3, CD8 and CD22. Peripheral lym phocytes were separated and cocultured with phytohemagglutinin (PHA) f or 72 h and assayed for CD25 by the APAAP technique. MAIN RESULTS: In untreated patients with EH (groups 2 and 3), there was a significant d own-regulation of CD3 and CD4 lymphocytes whereas the proportion of ma ture CD22 cells increased. In group 3 there was a significant down-reg ulation of CD25 with PHA stimulation. A negative correlation was obser ved between CD25 and diastolic pressure upon pooling the results of gr oups 2 and 3. No significant alteration in these parameters was observ ed following control of blood pressure with drugs for up to two weeks. CONCLUSIONS: In this small group of patients with untreated EH, a sig nificant alteration in the lymphocytic repertoire was observed. Whethe r this will be found in large groups of hypertensives remains to be se en.