Immunoglobulin G subclass deficiency in adult patients with chronic obstructive lung diseases

Background: Immunoglobulin G subclass deficiency (IgGSCD) is a relative common primary immunodeifiency disease and the association of chronic obstructive lung diseases (COLD) with disturbance in IgG subclass has been recognized. However, there has been controversy of a true biological significance of IgGSCD in patients with COLD. Objective: A retrospective review was conducted to characterize the clinical features of IgGSCD in patients with COLD. Methods: We reviewed the charts of 86 patients with bronchial asthma or chronic obstructive pulmonary disease having IgGSCD during 10 yrs. Subjects, according to the 10 warning signs by the Jeffrey Modell Foundation, were divided into two groups: group I (n=11) met the criteria: and group II (n=61) were without recurrent infections. Results: A total of 72 patients were enrolled. The male to female ratio was similar (35:37) and mean age was 62.8 ±15.3 yrs. Mean FEV1% was 67.5 ± 27.5%. The major underlying diseases were bronchiectasis (n=23), and history of tuberculosis (n=20). Isolated IgG3 deficiency is the most common subclass deficiency (72.2%), followed by IgG4 (6.9%), combined with IgG3 and other types (15.2%) and isolated IgG4 (n=6, 8.3%). The annual numbers of antibiotics course and the number of hospitalization related to infectious causes were significantly higher in group I than group II (p<0.0001 and p=0.012, respectively). In both groups, the most common infectious disease was pneumonia, followed by rhinosinusitis, zoster, and otitis media. Conclusions: IgG3 subclass deficiency was the most common type and lower levels of IgG subclasses were associated with an increased susceptibility to respiratory infection in patients with COLD.