Clinicopathologic, immunophenotypic and ultrastructrual analyses of ATLL patients with cutaneous involvement.

OBJECTIVE: To study 4 cases of adult T-cell leukemia/lymphoma (ATLL) associated with cutaneous lesions for clinicopathology, immunophenotype, human T-cell leukemia/lymphoma virus type I (HTLV-I) provirus DNA and their ultrastructure. At the same time, HTLV-I provirus DNA of ATLL patients were also compared with 18 cases of cutaneous lymphoma (CL), two cases of actinic reticuloid as well as two cases of lymphocytic infiltration.

METHODS: Immunohistochemistry studies were carried out on the infiltrating cells using monoclonal antibodies against CD45-RO, CD20, CD68 on paraffin-embedded sections by ABC method and using monoclonal antibodies against CD3, CD4 and CD8 with indirect immunofluorescence (IIF) on frozen sections. Skin biopsies were examined by electron microscope. Serum and bone marrow cells were tested for antibodies against HTLV-I-associated antigen by IIF, and HTLV-I provirus DNA was examined by PCR method.

RESULTS: The research showed four patients with ATLL manifesting cutaneous lesions, were subsequently found with additional systemic symptoms, as extensively enlarged superficial lymph node, abnormal increased IL-2 receptor, flower-like cells in their peripheral blood and marrow. The HTLV-I provirus DNA was positive in the peripheral blood, bone marrow, cutaneous lesions and lymph node biopsy specimens by using PCR amplification of specific HTLV-I fragment while 18 cases of the CL were negative for HTLV-I. The special ultrastructure of skin lesions was also found in ATLL patients.

CONCLUSIONS: The cutaneous involvement in ATLL is a type of cutaneous T cell lymphoma (CTCL) but shows some differential immunological markers for differential diagnosis. The examination of HTLV-I antibodies or HTLV-I provirus DNA is necessary for diagnosis of ATLL. The ultrastructural characteristics in skin lesions of ATLL were of atypical lymphocytes and mononuclear cells invading the epidermis, and the mononuclear cells are possessing the phagocytic function and phagocytizing the degenerated epidermic cells or lymphocytes.