Polyclonal bence jones proteinuria associated with reactive plasmacytosis

A 43 year old black male patient presented with progressive respiratory symptoms, fever and malaise of short duration accompanied by mild epistaxis. Physical examination revealed generalised lymphadenopathy and hepatosplenomegaly. Peripheral blood examination showed a striking plasmacytosis. Further investigation revealed Bence Jones proteinuria consisting of both kappa and lambda light chains. There was no monoclonal peak on serum electrophoresis and cytoplasmic immunoglobulin and gene rearrangement studies on the peripheral blood plasma cells demonstrated polyclonality. The possible role of Epstein-Barr virus in stimulating B cell proliferation in this case is discussed.