Introduction
Hypogammaglobulinemia has been frequently found in adult patients with severe sepsis and septic shock. Furthermore, it seems that at least a low serum level of IgM is correlated with higher mortality in sepsis. The mechanisms of hypogammaglobulinemia in septic shock have not yet been explained. It has been hypothesized that outflow of immunoglobulins into the extravascular space due to increased capillary permeability could reduce immunoglobulin serum concentrations. Angiopoietin-2, which directly disrupts the endothelial barrier, is markedly elevated in sepsis and other inflammatory states and its serum level has been correlated with microvascular leakage, end-organ dysfunction and death in sepsis.