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

Patients treated with allogeneic bone marrow transplantation (BMT) suffer f rom a deficient humoral immunity during the post-transplant period. To prev ent infections patients may receive prophylactic intravenous immunoglobulin (IVIG) therapy from 1 week before to 3 months after BMT. We have studied t he effect of IVIG treatment on reconstitution of immunoglobulin repertoires in transplanted patients. Sera obtained from 13 IVIG-treated and 31 non-IV IG-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 r eactivity profiles against antigens derived from human liver, muscle and sk in as well as Staphylococcus epidermidis protein extracts were similar in b oth patient groups and in controls. Both IgG and IgM reactivity profiles ar e, however, less heterogeneous among the individuals in the IVIG-treated pa tient group. Around 1 year after BMT the heterogeneity of the IgM reactivit y profiles against allogeneic protein extracts is much lower in the IVIG-tr eated group compared to the non-IVIG-treated group and the healthy controls . This effect remains months to years after the IVIG treatment has been com pleted. Our results suggest that IVIG influences selection of the natural a ntibody repertoire mediated by the variable (V)-region during reconstitutio n after BMT.