Immunoglobulin therapy to control lung damage in patients with common variable immunodeficiency.

Background: Lung damage progression is the most frequent condition in patients with common variable immunodeficiency (CVID). Appropriate immunoglobulin dose adjustments and follow-up guidelines to evaluate this have not been well established.

Objective: To assess the evolution of lung damage once stable residual serum levels of IgG over 600 mg/dl had been achieved.

Methods: A prospective study was conducted in 24 adult patients consecutively diagnosed with CVID, with no previous intravenous immunoglobulin (IVIG) treatment. IVIG dose, total serum IgG level, bacterial infection rate, pulmonary function tests (PFTs) and high resolution computed tomography (HRCT) of the thorax were monitored over 2 years. Moreover, outcome data were determined by measurement of chronic pulmonary disease (CPD).

Results: IVIG dose variability (205-372 mg/kg/21 days) to obtain the required serum IgG levels was determined. Patients with CPD needed higher doses than those without CPD (p=0.045). A significant reduction in severe and mild infections/patient-year was observed during treatment. Overall, there were no changes in PFTs and HRCT scores in patients without CPD, but both improved in patients with CPD. An increase of over 15% in overall HRCT score was detected in two patients without evidence of impairment in either clinical status or PFT values.

Conclusions: Residual levels of total IgG over 600 mg/dl may help prevent progression of lung damage in patients with CVID. Levels of IgG, clinical manifestations and PFTs seem sufficient for routine follow-up. HRCT examination of the thorax, at least biennially, may help to identify patients in whom lung injury is progressing even though they may remain symptom-free and with stable PFTs.