Intravenous immunoglobulin as potential adjunct therapy for interstitial lung disease

Intravenous Ig (IVIg) is a pooled plasma product consisting primarily of monomeric IgG. For the past several decades, the use of IVIg has expanded to include the treatment of various autoimmune and inflammatory disorders, including Kawasaki's disease, antineutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosis, and the inflammatory myopathies. IVIg is thought to exert its immunomodulatory effects through a variety of mechanisms: neutralization of pathogenic autoantibodies; alteration of immune cell effector function; suppression of cytokine and chemokine activity; and interference with complement activation. Interstitial lung disease (ILD) is a frequent complication of autoimmune disorders and connective tissue diseases, and the presence of ILD is associated with significant morbidity and mortality. Although there are currently no large studies to support the use of IVIg in the treatment of ILD, it is being used off-label with increasing frequency for refractory cases that have failed to respond to standard immunosuppression. Although associated with less systemic toxicity and global immunosuppression than traditional agents, IVIg is much more costly. Therefore, although the routine use of IVIg to treat ILD is not currently recommended, future studies to determine its role in pulmonary disease are warranted.