Therapy with interleukin-2 induces the systemic release of phospholipase-A2.
Therapy with interleukin-2 (IL-2) induces remissions in some forms of cancer. This treatment however, is accompanied by side-effects which, in part, may be mediated by the formation of eicosanoids and platelet-activating factor. We investigated the systemic release of phospholipase A2 (PLA2), a rate-limiting enzyme in the formation of these lipid mediators, in patients receiving IL-2. In a pilot study of 4 patients we observed an increase in PLA2 activity in serial plasma samples obtained during the first day after a bolus infusion of IL-2, which increase closely correlated with that of antigen levels of secretory phospholipase A2 (sPLA2) as measured by enzyme-linked immunosorbent assay (r = 0.92; P < 0.001). In 20 patients, receiving 12 x 10(6)-18 x 10(6) IU IL-2/m2, we then investigated the course of antigenic levels of sPLA2 in relation to those of the cytokines tumour necrosis factor alpha (TNF) and interleukin-6 (IL-6) (both cytokines may induce sPLA2 in vivo). From 4 h on, sPLA2 levels significantly increased, reaching a peak 24 h after the IL-2 infusion. Subsequent IL-2 infusions even induced a further increase of sPLA2. This increase of sPLA2 was presumably not due to a direct effect of IL-2 on, for example, hepatocytes, since this cytokine, in contrast to IL-1, IL-6, TNF and interferon gamma, was not able to induce the synthesis of sPLA2 by Hep G2 cells in vitro. Consistent with this, plasma levels of TNF and IL-6 in the patients rose, reaching peak levels before a zenith of sPLA2 occurred, i.e. at 2 h and 4 h after the start of the IL-2 infusion respectively. sPLA2 levels significantly correlated with the development of the side-effects increase in body weight (r = 0.49; P < 0.0001) and decrease in mean arterial blood pressure (r = 0.40; P < 0.0001). Moreover, maximum sPLA2 levels induced by IL-2 were higher in patients who had progressive disease after therapy than in patients who had stable disease or a partial response.
Central Laboratory of the Netherlands Red Cross Blood Transfusion, Amsterdam, The Netherlands.
G J
GJ
Wolbink
C
C
Schalkwijk
J W
JW
Baars
J
J
Wagstaff
H
H
van den Bosch
C E
CE
Hack
D006801:Humans; D007376:Interleukin-2 / Q000009:adverse effects*; D015850:Interleukin-6 / Q000096:biosynthesis; D009369:Neoplasms / Q000628:therapy*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D015430:Weight Gain
D007376:Interleukin-2; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D010741:Phospholipases A; D054467:Phospholipases A2