Monoclonal B-cell lymphocytosis in early childhood. A case report.

A case is reported of a 12-year-old girl with a benign course of a lymphocytosis through years associated with splenomegaly. The lymphocytes simultaneously expressed a monoclonal B-cell phenotype of IgM-kappa and a mature T-antigen using the monoclonal OKT1 antibody. Due to her stable condition, no treatment was required. The immunological results suggest the possibility of an early childhood B-cell chronic lymphoid leukemia.