TY - JOUR
T1 - Activation of the complement system during immunotherapy with recombinant IL-2. Relation to the development of side effects
AU - Thijs, L. G.
AU - Hack, C. E.
AU - Strack Van Schijndel, R. J.M.
AU - Nuijens, J. H.
AU - Wolbink, G. J.
AU - Eerenberg-Belmer, A. J.M.
AU - Van Der Vall, H.
AU - Wagstaff, J.
PY - 1990
Y1 - 1990
N2 - Therapy with high doses of rIL-2 is complicated by the occurrence of hypotensive reactions and the development of a vascular leakage syndrome (VLS). In four patients, who together received seven cycles of high doses of IL-2 (up to 12 x 106 U per m2 per day), and who developed these side effects, we observed an unexpected increase in plasma levels of C3a, indicating activation of the complement system. C3a levels markedly increased during IL-2 therapy from 4 nmol/liter (mean level) before therapy to 23 nmol/liter at the end of the cycle. Activation of C3 occurred via the classical pathway inasmuch as C4a levels also increased during therapy. Mean daily C3a levels correlated with signs of the VLS, such as daily weight gain (p<0.001) and albumin levels (inverse correlation, p<0.001). In five additional patients, who together received seven cycles of lower doses of IL-2 (2 x 106 U per m2 per day) and who did not develop a VLS, only moderate increases in C3a levels (up to 13 nmol/liter) were observed. The highest levels at the first day of the regimen (mean: 7 nmol/liter) occurred 8 h after the IL-2 infusion. Thus, administration of IL-2 induces a dose-dependent activation of the complement system in vivo, which appeared to be related to the development of side effects of this therapy, such as the VLS.
AB - Therapy with high doses of rIL-2 is complicated by the occurrence of hypotensive reactions and the development of a vascular leakage syndrome (VLS). In four patients, who together received seven cycles of high doses of IL-2 (up to 12 x 106 U per m2 per day), and who developed these side effects, we observed an unexpected increase in plasma levels of C3a, indicating activation of the complement system. C3a levels markedly increased during IL-2 therapy from 4 nmol/liter (mean level) before therapy to 23 nmol/liter at the end of the cycle. Activation of C3 occurred via the classical pathway inasmuch as C4a levels also increased during therapy. Mean daily C3a levels correlated with signs of the VLS, such as daily weight gain (p<0.001) and albumin levels (inverse correlation, p<0.001). In five additional patients, who together received seven cycles of lower doses of IL-2 (2 x 106 U per m2 per day) and who did not develop a VLS, only moderate increases in C3a levels (up to 13 nmol/liter) were observed. The highest levels at the first day of the regimen (mean: 7 nmol/liter) occurred 8 h after the IL-2 infusion. Thus, administration of IL-2 induces a dose-dependent activation of the complement system in vivo, which appeared to be related to the development of side effects of this therapy, such as the VLS.
UR - http://www.scopus.com/inward/record.url?scp=0025217196&partnerID=8YFLogxK
M3 - Article
C2 - 2313099
SN - 0022-1767
VL - 144
SP - 2419
EP - 2424
JO - Journal of Immunology
JF - Journal of Immunology
IS - 6
ER -