Prophylactic intravenous immunoglobulin treatment influences serum immunoglobulin M repertoire development after allogeneic bone marrow transplantation.

Patients treated with allogeneic bone marrow transplantation (BMT) suffer from a deficient humoral immunity during the post-transplant period. To prevent infections patients may receive prophylactic intravenous immunoglobulin (IVIG) therapy from 1 week before to 3 months after BMT. We have studied the effect of IVIG treatment on reconstitution of immunoglobulin repertoires in transplanted patients. Sera obtained from 13 IVIG-treated and 31 non-IVIG-treated patients before and at different time points after BMT, ranging from 3 days to 3 years, and from 18 healthy controls, were analyzed using a quantitative immunoblot system. The average immunoglobulin (Ig)M and IgG reactivity profiles against antigens derived from human liver, muscle and skin as well as Staphylococcus epidermidis protein extracts were similar in both patient groups and in controls. Both IgG and IgM reactivity profiles are, however, less heterogeneous among the individuals in the IVIG-treated patient group. Around 1 year after BMT the heterogeneity of the IgM reactivity profiles against allogeneic protein extracts is much lower in the IVIG-treated group compared to the non-IVIG-treated group and the healthy controls. This effect remains months to years after the IVIG treatment has been completed. Our results suggest that IVIG influences selection of the natural antibody repertoire mediated by the variable (V)-region during reconstitution after BMT.