DETERMINATION OF CAPILLARY LEAKAGE DUE TO RECOMBINANT INTERLEUKIN-2 BY MEANS OF NONINVASIVE CONDUCTIVITY MEASUREMENTS

One of the most common side effects of treatment with recombinant inte rleukin-2 (IL-2) is capillary leakage. Its genesis is not completely u nderstood. The aim of the study was to determine whether capillary lea kage can be monitored by means of a noninvasive conductivity technique and to study its starting point. Eight patients with advanced renal c ell cancer were studied in a medium care section of the Department of Medical Oncology, University Hospital over 4 days during treatment ses sions of continuous, intravenously administered IL-2 (mean dose of 15. 6 X 10(6) IU . m-2 . day-1). The fluid shift from the intravascular to the extra- and intracellular compartments was monitored by means of n oninvasive conductivity measurements. Changes in blood volume were cal culated from serial erythrocyte counts. The clinical parameters of cap illary leakage (oliguria, positive fluid balance, and gain in mass) we re recorded. The mean gain in mass was 9% after 4 days of IL-2 treatme nt. The extracellular fluid volume increased significantly [46 (SD 23. 2)%; P<0.01], whereas the intracellular fluid volume did not change. T he increase in blood volume (BV) amounted to 7% (P<0.05). The decline in albumin concentration was significantly more than the increase in B V [38 (SD 4.3)%; P<0.01], indicating capillary albumin leakage. The ma in changes were observed after the 2nd day of treatment. From this stu dy, it is suggested that conductivity measurements are a suitable meth od to monitor capillary leakage induced by IL-2, and could be used to detect the exact onset and severity of this leakage. The leakage start ed within the first 24 h of treatment and was detected as a fluid shif t from the intravascular to the extracellular space, while the intrace llular compartment remained stable. These measurements could be useful during intervention studies with the aim of preventing this adverse e ffect of IL-2.