HUMAN-LEUKOCYTES CONTAIN ANGIOTENSIN-I, ANGIOTENSIN-II AND ANGIOTENSIN METABOLITES

Angiotensin I(ANG I) and angiotensin II (ANG II) were measured radioimmunologically in human leukocytes extracted with a mixture of acetone, 1N HCl and water (40:1:10 vol). The analytical recoveries of I-125-ANG I and I-125-ANG II, which were added prior to extraction, were 92.00+/-3.10 and 99.19+/-0.91% (mean+/-SEM; n = 12). The concentration of ANG I- and ANG II-like material in leukocytes from healthy volunteers was 32.04+/-3.64 and 13.05+/-1.26 fmol/mg protein (n = 24). The immunoreactive material could be characterized on HPLC as Ile(5)-ANG I, Ile(5)-ANG II and angiotensin metabolites such as Ile(4)-ANG III, Ile(3)-ANG II hexapeptide, Ile(2)-ANG II pentapeptide and Ile(1)-ANG II tetrapeptide. From the ANG I-immunoreactive material determined in the extracts, 26% could be characterized on HPLC as Ile(5)-ANG I. The ANG II-immunoreactive material present in the extracts could be separated on HPLC into 44% Ile(5)-ANG II, 14% Ile(4)-ANG III, 7% Ile(3)-ANG II hexapeptide, 4% Ile(2)-ANG II pentapeptide and 8% Ile(1)-ANG II tetrapeptide. Patients with a history of anaphylactic reactions to bee or wasp venom showed significantly reduced ANG II concentrations in their leukocytes as compared to controls (6.76+/-0.76 fmol ANG II/mg protein, n = 22, vs. 13.05+/-1.26 fmol ANG II/mg protein, n = 24; p<0.05). A significant correlation between the severity of clinical symptoms and the ANG II levels was found for grade I and II reactions (p<0.05). Successful immunotherapy induced a 5-fold increase in ANG II as compared to controls (61.85+/-9.73 fmol ANG II/mg protein, n = 16, vs. 13.05 +/- 1.26 fmol ANG II/mg protein, n = 24; p<0.05) and a 9-fold increase as compared to patients without immunotherapy (61.85+/-9.73 fmol ANG II/mg protein, n = 16, vs. 6.76+/-0.76 fmol ANG II/mg protein, n = 22; p<0.05).