Alemtuzumab in Treating Patients With Relapsed or Refractory Advanced Mycosis Fungoides or Sézary Syndrome

DISEASE CHARACTERISTICS: * Histologically confirmed mycosis fungoides or Sézary syndrome * Stage IB-IVB * Measurable disease * One or more indicator lesions * No prior radiotherapy to areas of measurable disease unless there is clear disease progression at the site or measurable disease outside the area of prior radiotherapy * Generalized erythrodermia patients with evaluable disease only are allowed * Must have failed at least 1 prior systemic therapy PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 OR * WHO 0-2 Life expectancy * At least 3 months Hematopoietic * WBC at least 3,000/mm\^3 * Absolute granulocyte count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic * Bilirubin no greater than 2.2 mg/dL * AST or ALT no greater than 2 times upper limit of normal (ULN) * Alkaline phosphatase no greater than 2 times ULN Renal * Creatinine no greater than 2.0 mg/dL Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * HIV negative * No acute infection requiring intravenous antibiotics * No other prior neoplasm except treated squamous cell or basal cell skin cancer, treated carcinoma in situ of the cervix, or other cancer that received surgical treatment only from which patient has been disease free for at least 5 years PRIOR CONCURRENT THERAPY: Biologic therapy * More than 4 weeks since prior biologic therapy Chemotherapy * More than 4 weeks since prior chemotherapy Endocrine therapy * More than 4 weeks since prior topical steroids Radiotherapy * See Disease Characteristics * At least 2 weeks since prior radiotherapy (local control or palliative) * No concurrent radiotherapy to any lesion Surgery * Recovered from prior major surgery Other * Recovered from prior therapy * No other concurrent proven or investigational antineoplastic agents