T-cell chronic lymphocytic leukemia: clinical aspects and laboratory findings of five patients. This study illustrates the main clinical aspects and laboratory findings for five patients suffering from T-cell chronic lymphocytic leukemia. They make up 5% of our observations in the Department of Oncology-Hematology at the Busto Arsizio Hospital. Three patients with phenotype CD3+/CD4+ showed a fast course with skin involvement and poor response to chemotherapy (mean survival: 12 months). The course of a patient with unusual phenotype CD3-/CD4+ associated with autoimmune hemolytic anemia and end-stage prolymphocytic transformation was better (survival: 58 months). For 12 years we have been observing a woman suffering from the recently defined CD3+/CD8+/HNK1+ large granular lymphocytes chronic lymphocytosis with associated neutropenia. The disease has good prognosis, with poor symptomatology even without therapy. This study supports the immunological classification of the chronic lymphoproliferative diseases of leukemia and lymphoma with different clinical aspects and prognoses. This method of classification may be important in the consideration of some therapeutical approaches.