Published Online: September 1, 2015
Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. While IgG replacement therapy (IVIG or subcutaneous Ig) prevents the development of severe infections, other complications still develop that significantly reduce quality of life and survival of CVID patients. Interstitial lung disease is one of the most common and dangerous complications of CVID. Effective treatment of CVID interstitial lung disease requires immunosuppression, but this therapy can increase risk of infections or other adverse outcomes in these patients that are already genetically immunosuppressed. Thus, how to identify the specific CVID patients that require immunosuppression to treat interstitial lung disease remains an important question for physicians.
In a retrospective study recently published in The Journal of Allergy and Clinical Immunology: In Practice, Maglione et al. analyze clinical and laboratory parameters commonly measured by physicians to find those associated with worsening interstitial lung disease in CVID. Parameters examined include pulmonary function test results as well as blood tests measuring levels of immunoglobulins, hemoglobin, platelets, and various types of immune cells. Fifteen CVID patients with interstitial lung disease and periodic pulmonary function testing over the course of 20 or more months were included.
Of the 15 CVID patients examined, 9 had significant physiologic worsening of pulmonary function test results. This demonstrated that many, but not all CVID patients have physiological worsening of interstitial lung disease over the course of 20 or more months of follow-up. Thus, CVID patients with interstitial lung disease could be separated into two groups on the basis of conventional pulmonary function testing: those with progressive worsening of interstitial lung disease and those with stable disease. Moreover, those patients with progressive interstitial lung disease could be identified by specific characteristics on routine laboratory testing: higher serum IgM levels, lower platelet counts, and increased dosage requirements of IgG replacement therapy.
While interstitial lung disease is known to be a dangerous complication of CVID that requires immunosuppression, the specific patients at risk for progression of this complication and in need of treatment have not been clearly defined. The study by Maglione et al. is the first to identify routinely measured pulmonary and laboratory characteristics with progression of interstitial lung disease in CVID. Thus, this report identifies clinical measurements useful to physicians to identify CVID patients at greatest risk of worsening lung disease and paves the way for larger studies to confirm these findings and apply them to therapeutic trials.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.