Interleukin-7 in Treating Patients With Metastatic Melanoma or Locally Advanced or Metastatic Kidney Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed diagnosis of 1 of the following: * Melanoma * Metastatic disease * Renal cell carcinoma * Locally advanced and unresectable disease OR metastatic disease * Refractory to standard therapy OR ineligible to receive standard therapy * Measurable or evaluable disease * Previously received high-dose interleukin-2 OR have a contraindication for this treatment * No previously untreated or unstable brain metastases * No splenic metastasis PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * Life expectancy ≥ 3 months * Absolute neutrophil count \> 1,000/mm\^3 * Platelet count \> 100,000/mm\^3 * PT/PTT ≤ 1.5 times upper limit of normal (ULN) * Creatinine \< 1.5 times ULN * AST and ALT \< 2.5 times ULN * Conjugated (Direct) bilirubin ≤ 1.25 times ULN * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * LVEF ≥ 45% by cardiac stress test (e.g., stress thallium, stress MUGA, dobutamine echocardiogram, or other stress test) for patients meeting any of the following criteria: * History of ECG abnormalities * Symptoms of cardiac ischemia * At least 50 years of age and over * Familial or personal history of heart failure * Previously treated with antimitotic agents susceptible to trigger heart failure * FEV\_1 \> 60% of predicted (for patients with a prolonged smoking history or symptoms of respiratory dysfunction) * No concurrent cognitive impairment or likelihood of developing cognitive impairment on study therapy * No concurrent splenomegaly or proliferative hematologic disease * No documented HIV positivity * No acute hepatitis A or hepatitis B or C * Positive hepatitis B serology indicative of previous immunization (i.e., HBs Ab positive and HBc Ab negative) allowed * Positive hepatitis C serology allowed provided HCV RNA load by PCR is negative * Resting blood pressure ≤ 140/90 mm Hg on standard antihypertensive therapy * Untreated hypertensive patients who received standard antihypertensive therapy allowed provided hypertension is well controlled * No QTc prolongation ≥ 470 msec * No prior history of cardiovascular disease, arrhythmias, or significant ECG abnormalities * No active infection requiring systemic treatment and/or hospitalization within the past 28 days * Patients who have completed therapy or are clinically stable on therapy, in the opinion of the investigator, are eligible * No history of autoimmune disease * No history of severe asthma * No history of medical or psychiatric disease that would preclude study treatment * No documented cirrhosis or documented acute hepatitis PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 2 weeks since prior systemic corticosteroid therapy * More than 4 weeks since prior and no other concurrent cytotoxic therapy, immunotherapy, biological agents (i.e., cytokines, growth factors, or monoclonal antibodies), or antitumor vaccines * More than 7 days since prior hepatotoxic drugs unless medically necessary * More than 2 days since prior alcohol consumption * More than 1 day since prior acetaminophen use * No prior splenectomy * No prior allogeneic hematopoietic stem cell transplantation or solid organ transplantation * No concurrent palliative therapy * No concurrent chemotherapy * No concurrent chronic anticoagulation (i.e., high-dose warfarin or heparin) * Warfarin dose 1 to 2 mg/day allowed * No concurrent chronic medications for asthma * No other concurrent investigational agents