Rheumatologic and autoimmune manifestations of primary immunodeficiency disorders.

PURPOSE OF REVIEW: Although it may seem paradoxical, primary immunodeficiency disorders are frequently complicated by autoimmune and inflammatory conditions. These conditions pose significant diagnostic and therapeutic challenges for clinicians caring for these patients. There have been a number of new insights into how immunodeficiencies can predispose to autoimmunity, and rheumatologists should understand the basis for and manifestations of autoimmunity in primary immunodeficiency disorders to more effectively care for these patients.

RECENT FINDINGS: A number of mechanisms have recently been found to link primary immunodeficiencies and autoimmunity, including increased homeostatic proliferation in primary immunodeficiencies associated with lymphopenia and defects in regulatory T cells in the Wiskott-Aldrich syndrome. Primary immunodeficiencies that affect the innate immune system can also lead to inappropriate inflammation through impairing negative regulatory mechanisms in innate immune cells.

SUMMARY: The realization that primary immunodeficiencies can also impair negative regulation of immune responses has provided a new framework for the understanding of autoimmunity associated with these conditions. These insights may lead to new, more targeted therapies for autoimmune complications in primary immunodeficiency patients.