[Restricted antibody diversity after bone marrow transplantation--homogeneous immunoglobulins]

After bone marrow transplantation, a prolonged dysregulation of humoral immunity, including restricted electrophoretic heterogeneity of serum immunoglobulins and the appearance of homogeneous immunoglobulin components, can be observed. The current study was undertaken to characterize further and define the posttransplantational incidence of monoclonal and oligoclonal immunoglobulins, as well as the clinical and laboratory correlations of these phenomena. For this purpose, serial serum protein (IgM, IgG, IgA and CRP) quantification, electrophoresis and immunofixation were performed on 29 patients undergoing allogeneic bone marrow transplantation for chronic myeloid leukemia. 23 out of the 29 patients developed transient oligoclonal and/or monoclonal gammopathies that appeared between 20 and 1750 posttransplantational days. No correlation, however, between the development of graft versus host disease, EBV or CMV infections, or any other symptoms and development of homogeneous immunoglobulin components was seen. Therefore, the development of oligoclonal and monoclonal gammopathies after bone marrow transplantation may be an ubiquitous finding reflecting the inadequacy, i.e. oligoclonality of the recovering B-cell system.