[Rearrangements of immunoglobulin heavy chain gene in Waldenstr"om's macroglobulinemia].

We investigated rearrangements of immunoglobulin heavy chain (Ig(H)) gene of the bone marrow mononuclear cells by Southern hybridization in 7 patients with Waldenström's macroglobulinemia. Three of 7 cases showed the rearrangement of Ig (H) gene. The cases with Ig (H) gene rearrangements showed high rates of CD19 and CD20 positive cells compared to the cases with no rearrangements. Two out of 3 cases included less than 3 g/dl IgM. On the other hand, 4 cases without rearrangements had lower percentage of B cells in the bone marrow and higher serum IgM (4/4; more than 3g/dl) than the cases with the rearrangements. Thus, the rearrangements of Ig (H) chain gene did not correlate with serum IgM level and related to the quantity of B cells in the bone marrow in WM.