The biological rationale for their administration can be found in the results of some studies demonstrating that not only low levels of IgG, IgM and IgA measured at the admission but also their failed increase during the ICU stay were associated with both the transition from severe sepsis to septic shock and with a reduced survival [30–32]; yet, despite these evidences, the role of ivIgGAM in the treatment of septic shock remains controversial notwithstanding their use began several decades ago. This evidence concerns the gene CD40LG and septic shock.