Studies on B-lymphocyte dysfunctions in severely burned patients.

We studied in vitro functional parameters of peripheral blood B-lymphocytes from severely burned patients (n = 10; burn injuries ranging from 25 to 72% TBSA). While the number of B-cells remained unchanged, B-cell proliferation induced by Staphylococcus aureus strain Cowan I (SAC) was normal or even enhanced at early and late phases postburn, but showed a marked suppression during the second to fourth week. A similar pattern was observed for the pokeweed mitogen (PWM)- or SAC-stimulated synthesis of immunoglobulin M (IgM), whereas IgG production was decreased over the whole postburn period monitored. Cytokine (interleukin 4)-induced B-cell activation as indicated by the expression of the CD23 surface antigen was impaired throughout the second to fifth week. In parallel, the release of the proteolytic cleavage product sCD23 which represents a B-cell growth and differentiation factor was reduced. Our data provide evidence that activation, proliferation, and differentiation processes of B-lymphocytes are impaired in severely burned patients, which may contribute to their enhanced susceptibility to infection and sepsis.