Metabolic and renal effects of interleukin-2 immunotherapy for metastatic cancer

The systemic administration of recombinant interleukin-2 (IL-2) either alone or in combination with lymphokine activated killer cells is a new approach to the immunotherapy of metastatic cancer in man. Renal toxicity is often a dose-limiting side effect of IL-2 administration. This prospective study of 17 consecutive patients receiving parenteral high dose IL-2 documents a reversible syndrome of hypotension, oliguria, fluid retention, azotemia and very low urinary excretion of sodium (median FeNa of 0.04%). The median nadir urinary uric acid to urinary creatinine ratio during IL-2 therapy was 0.2. This IL-2 regimen induces a reversible renal hypoperfusion syndrome (pre-renal azotemia) without evidence of acute uric acid nephropathy. Hypophosphatemia [median serum phosphorus of 1.9 mg/dl (0.61 mmol/l)] prompted further study of tubular function. Urinary excretions of phosphorus, calcium and magnesium were very low. Arterial blood gases revealed hyperventilation without alkalemia. The hypophosphatemia probably reflects increased utilization of inorganic phosphorus by rapidly proliferating lymphoid cells.