"How I manage" IgG4-Related Disease.

IgG4-related disease (IgG4-RD) is an immune-mediated disease driven by interactions on several levels between cells of the B and T lineages. A key driver of IgG4-RD is believed to be a novel CD4+ cytotoxic T lymphocyte that bears SLAM-F7 on its surface. This cell is presumed to be sustained by continuous antigen presentation by cells of the B cell lineage, particularly plasmablasts. Because IgG4-RD has been recognized for fewer than 15 years as a unified diagnostic entity, no controlled clinical trials or few prospective studies of any sort have been performed. Although progress in understanding disease pathophysiology will likely lead in due course to disease-specific therapies-undoubtedly with implications for other immune-mediated diseases-at this juncture, the management of IgG4-RD remains more an art than a science, driven largely by the published clinical experience of only a few centers of expertise. We identify here six common management dilemmas in IgG4-RD and describe our typical approach to the management of each one.