High dose intravenous IgG in immune diseases: A rational approach to off-label uses [La prescrizione delle immunoglobuline IgG ad alte dosi in malattie del sistema immunitario. Criteri di uso off-label e razionale: Critica della ragion pratica]

Treatment with intravenous immunoglobulins IgG has been approved for immunodeficiencies and various immunerelated diseases, including thrombocytopenic purpura, demyelinating neuropathies, Guillain-Barré syndrome, and Kawasaki disease. In the past thirty years, off-label Intravenous Immunoglobulin IgG treatment of an increasing number of disorders has shown to be a useful approach with good clinical results. Here we review the rational approach to off-label use of high dose Intravenous Immunoglobulins IgG in several diseases, and the complex different mechanisms of action, including expression and function of Fc receptors, modulating idiotype network, complement and cytokine interactions, and natural antibodies role. The potential of recently introduced subcutaneous administration of immunoglobulins IgG is briefly discussed.