Key Message
One randomized controlled trial and one non-randomized, retrospective, observational study were identified describing the clinical effectiveness of off-label use of intravenous immunoglobulin for the treatment of solid organ transplant rejection. Evidence of moderate quality from one randomized controlled trial investigating intravenous immunoglobulin combined with rituximab versus placebo in 25 renal transplant patients with chronic antibody mediated rejection indicated that there was no important effect on renal function. Evidence of limited quality from one non-randomized, retrospective observational study investigating intravenous immunoglobulin versus methylprednisolone in 39 renal transplant patients with antibody mediated rejection indicated that there was a significant improvement in renal function. Further evidence from larger, long-term studies, including investigating other types of organ transplants, is necessary to reduce uncertainty.