Denileukin Diftitox in Treating Patients With Metastatic Melanoma or Metastatic Kidney Cancer

DISEASE CHARACTERISTICS: * Diagnosis of 1 of the following: * Melanoma * Kidney cancer * Metastatic disease * Measurable disease * Documented disease progression while receiving standard therapy * No resectable local or regional disease PATIENT CHARACTERISTICS: Age * 16 and over Performance status * ECOG 0-2 Life expectancy * More than 3 months Hematopoietic * WBC ≥ 3,000/mm\^3 * Platelet count ≥ 90,000/mm\^3 * Lymphocyte count ≥ 500/mm\^3 * No concurrent coagulation disorders Hepatic * Bilirubin ≤ 2.0 mg/dL (\< 3.0 mg/dL for patients with Gilbert's syndrome) * AST and ALT \< 3 times normal * Albumin ≥ 2.5 g/dL * Hepatitis B surface antigen negative * Hepatitis C antibody negative Renal * Creatinine ≤ 2.0 mg/dL Cardiovascular * Normal thallium stress test\* * No prior myocardial infarction * No history of severe coronary artery disease * No major medical illness of the cardiovascular system NOTE: \*For patients \> 50 years of age OR who have a history of cardiovascular disease Pulmonary * No major medical illness of the respiratory system Immunologic * HIV negative * No active systemic infection * No presence of opportunistic infections * No primary or secondary immunodeficiency * No autoimmune disease * No other known immunodeficiency Other * No sensitivity to denileukin diftitox or any of its components (e.g., diphtheria toxin, interleukin-2, or excipients) * Willing to undergo leukapheresis * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy * Prior treatment with interleukin-2 allowed provided the patient's disease status required this therapy Chemotherapy * Recovered from prior chemotherapy Endocrine therapy * No concurrent systemic steroids Radiotherapy * Recovered from prior radiotherapy Surgery * Not specified Other * More than 3 weeks since prior systemic anticancer therapy * No other concurrent systemic anticancer therapy