Decrease in interleukin 2-induced vascular leakage in the lungs of mice by administration of recombinant interleukin 1 alpha in vivo.

The administration of interleukin 2 (IL-2) to mice and humans is limited by the induction of a dose-dependent increase in vascular permeability causing a vascular leak syndrome (VLS). We have investigated the impact of the injection of recombinant interleukin 1 alpha (IL-1 alpha) on the VLS induced by IL-2 by measuring the extravasation of 125I-albumin into tissues and by assessing wet and dry lung weights. IL-1 alpha alone did not induce any significant extravasation of radiolabeled albumin. IL-2 alone, however, caused a significant increase in the extravasation compared to control lungs. IL-1 alpha injection along with IL-2 significantly reduced the IL-2-induced extravasation of radiolabeled albumin [9,886 +/- 533 (SEM) cpm were observed in IL-2 and IL-1 alpha-treated lungs compared to 14,172 +/- 2,628 cpm in lungs treated with IL-2 alone (P less than 0.02)]. IFN-alpha in combination with IL-2 produced more severe vascular leakage than caused by IL-2 alone. IL-1 alpha also significantly decreased (P less than 0.05) the vascular permeability induced by the combination of IFN-alpha and IL-2. We observed 44,811 +/- 13,131 cpm in IFN-alpha- and IL-2-treated lungs compared to 18,350 +/- 2,622 cpm in IFN-alpha-, IL-2-, and IL-1 alpha-treated lungs. The IL-2- and IFN-alpha-induced increase in lung water weight was also reduced significantly by the addition of IL-1 alpha. The decrease in vascular leakage was dependent on the dose and timing of IL-1 alpha administered. When recombinant IL-1 alpha was given as a single i.p. injection, 24 h before the injection of IL-2 (or Hanks' balanced salt solution) or IL-2 and IFN-alpha no abrogation of the VLS was observed. Although IL-1 alpha decreased VLS significantly in mice treated with IFN-alpha and IL-2 the survival of mice was not improved by the simultaneous administration of IL-1 alpha. Histologically, treatment with IFN-alpha and IL-2 produced marked perivascular and intraalveolar edema which was completely eliminated by the addition of IL-1 alpha. However, some perivascular edema in IL-1 alpha-treated mice remained which was equivalent to that caused by IL-2 alone. Treatment of MCA-106 induced pulmonary metastases was enhanced by the administration of IFN-alpha and IL-2 together.(ABSTRACT TRUNCATED AT 400 WORDS)