Background and objective:  Pulmonary disease is the most common complication in patients with common variable immunodeficiency (CVID) or X‐linked agammaglobulinaemia (XLA). Pulmonary disease may progress despite immunoglobulin replacement therapy. In this study pulmonary complications were compared in patients with CVID or XLA.

Methods:  Pulmonary complications were evaluated in 115 patients (76 with CVID and 39 with XLA) by reviewing hospital records of chest infections, pulmonary function tests and high‐resolution CT scans.

Results:  Thirty‐two patients with XLA (82%) presented with 59 episodes of pneumonia before diagnosis, whereas 15 patients (38.4%) experienced pneumonia after immunoglobulin replacement therapy (1.67 vs 0.45 episodes per patient per year). Among the CVID patients, 196 episodes of pneumonia were documented in 59 patients (77.6%) before diagnosis, while 36 patients (47.3%) experienced pneumonia after therapy (1.11 vs 0.58 episodes of pneumonia per patient per year). Forty‐seven (41%) patients (38 with CVID and 9 with XLA) developed chronic lung disease. The CVID patients developed more complications, including bronchiectasis and lymphoid interstitial pneumonitis, than the XLA patients.

Conclusions:  Patients with CVID had a greater likelihood of developing lung disease, possibly due to delayed diagnosis and immune dysregulation, as compared with XLA patients. Early diagnosis of patients with primary antibody deficiencies and adequate i.v. immunoglobulin replacement therapy substantially reduces the number of pulmonary infections. However, CVID patients are prone to progression of lung disease despite optimal immunoglobulin therapy because of the nature of the disease. This important issue should be addressed in further studies.