Effects of intravenous immunoglobulin on hemorrhage-induced alterations in plasma cell repertoires. Hemorrhage produces decreases in serum immunoglobulin (Ig) levels and alterations in the number and frequency of B cells producing antibodies against bacterial antigens. These abnormalities in immune response may contribute to the increased susceptibility to infection after injury and hemorrhage. To examine the relationship between serum Ig levels and bacterial antigen-specific plasma cell numbers and frequencies after blood loss, we treated hemorrhaged mice with intravenous Ig (IVIG). Hemorrhaged mice given IVIG had increased total numbers of splenic plasma cells compared with normal or hemorrhaged, untreated mice. Immunization with the bacterial polysaccharide antigen levan immediately after hemorrhage resulted in approximately 60% fewer levan-specific splenic plasma cells than those seen in normal unhemorrhaged mice. Treatment of hemorrhaged mice with IVIG did not correct the decrease in levan-specific plasma cells. These results demonstrate that hemorrhage-induced alterations in the numbers and frequencies of bacterial antigen-specific B cells are not related to changes in serum Ig levels and cannot be corrected through administration of IVIG. 