Hemorrhage in mice induces alterations in immunoglobulin-secreting B cells.

Infections remain the major cause of late morbidity and mortality after hemorrhage, trauma, and burns. Abnormalities in immune response appear to play a major role in the increased susceptibility to infection in this setting. In the present study, the effect of hemorrhage on the numbers of splenic B cells and isotype-specific immunoglobulin(Ig)-secreting cells in mice was investigated. No changes in the total number of splenocytes or of splenic B cells were found after hemorrhage. Decreases of greater than 40% in the total number of Ig-producing cells as well as in the numbers of B cells secreting IgM, IgA, and IgG2b were found during the period of 2 to 96 h posthemorrhage. Subsequent increases in the numbers of cells secreting IgA, IgG1, IgG2a, and IgG3 were present 96 to 144 h after hemorrhage. Total serum Ig levels fell by approximately 40% 3 days after hemorrhage, and then returned to normal within 5 days posthemorrhage. These results demonstrate that hemorrhage produces marked alteration in B-cell populations and serum Ig levels.