POLYCLONAL B-CELL CHRONIC LYMPHOPROLIFERATIVE DISEASE WITH HAIRY-CELLMORPHOLOGY - A CASE-REPORT AND CLONAL STUDIES

We describe a patient who has a chronic polyclonal B lymphocyte prolif eration with a hairy-cell appearance, A 48-year-old Japanese woman wit h marked splenomegaly, systemic lymphadenopathy, and leukocytosis was referred to our hospital. Laboratory examination revealed marked polyc lonal IgG hypergammaglobulinemia. Morphologic examination of the patie nt's peripheral blood, including May-Giemsa staining and scanning elec tron microscopy, showed a monotonous proliferation of hairy-appearing mature lymphocytes. An immunophenotypic study revealed an expansion of cells with mature B cell antigens positive for CD11c; however, light- chain restriction was not seen, The lack of both immunoglobulin heavy- chain and T cell receptor gene rearrangements by Southern blot analysi s indicated the polyclonal nature of the proliferating B cells, This w as confirmed further by a clonal analysis of the patient's lymphocytes using an X-chromosome-linked restriction fragment polymorphism within the X-linked phosphoglycerate kinase (PGK) gene. Since chronic B cell lymphoproliferation with a hairy cell appearance has not been describ ed previously, this case might be extremely rare, and has important im plications for the pathogenesis of mature B cell lymphoproliferative d iseases, including hairy cell leukemia. (C) 1996 Wiley-Liss, Inc.