Impaired antibody production in blunt trauma. Possible role for T cell dysfunction

This study investigates mechanisms of impaired humoral immune response in a well-defined population of blunt trauma patients (n = 18, Injury Severity Score greater than or equal to 20). Spontaneous and pokeweed mitogen-induced polyclonal immunoglobulin production were assessed in cultures of peripheral blood mononuclear cells. The proliferative response to alloantigen and mitogen was assessed in parallel by the mixed lymphocyte reaction and pokeweed mitogen-induced blastogenesis, respectively. Pokeweed mitogen-induced IgG and IgM production was significantly reduced in trauma patients compared with controls. This effect was not reversed by depletion of adherent cells or by the addition of indomethacin. Exogenous interleukin 2 was also ineffective. However, the addition of normal T cells or supernatants from isoantigen-stimulated cultures of these cells to patient B cell-enriched cultures significantly enhanced (by 1.4- to 5.1-fold) the antibody response to pokeweed mitogen. Thus, suppression of humoral antibody response in blunt trauma patients may be due to failure of T-cell mediated help, resulting in insufficient secretion or activity of cytokines required for adequate B cell activation, proliferation, or differentiation into immunoglobulin-secreting cells.