Primary immunodeficiency-related bronchiectasis in adults: comparison with bronchiectasis of other etiologies in a French reference center

Background: Bronchiectasis is a heterogeneous disease depending on etiology. It represents the most frequent non-infectious pulmonary complication of primary immunodeficiencies (PID). We investigated whether bronchiectasis associated with PID had a distinct course in comparison to bronchiectasis of other causes. Methods: Retrospective single-center study of adult patients diagnosed with non-cystic fibrosis bronchiectasis with more than 5 years of follow-up and at least 4 pulmonary functional tests available at one year apart. They were divided into three groups: PID-related bronchiectasis, idiopathic/post infectious-related bronchiectasis and other causes of bronchiectasis. Respiratory functional data and clinical outcomes were compared. Results: Of 329 patients with bronchiectasis diagnosed in Foch Hospital (Suresnes, France), 98 patients fulfilled the selected criteria (20 PID-related cases, 39 idiopathic or post-infectious cases, and 39 cases with other causes). Median time of follow-up was 9.5 years. Groups were similar concerning initial characteristics (female 70.4%, never smokers 59.2%, mild severity bronchiectasis according to the FACED score and median FEV1 at diagnosis 73.5% predicted values [Q1-Q3: 53.75-90.5]), except PID patients who were younger (median age of 51.5 vs 62 years, p = 0.02). Eighty-five percent of PID patients received immunoglobulin substitution (median trough level was measured at 10.5 g/dl [10;10.92]). Global median FEV1 annual decline was 25.03 ml/year [8.16;43.9] and 19.82 ml/year [16.08;48.02] in the PID patients group. Forty-five percent of patients had bacterial colonization, pneumoniae occurred in 56% of patients and median exacerbation annual rate was 0.8 [0.3-1.4]. Hemoptysis occurred in 31.6% of patients. Global mortality rate was 11.2%. We did not record any significant difference for all clinical and functional outcomes between patients with PID and other etiologies. The median decline in FEV1 was similar in the three groups. Conclusions: The course of PID-related bronchiectasis was similar to bronchiectasis of other causes. Provided that patients receive immunoglobulin replacement, the course of PID-related bronchiectasis seems to be independent of the underlying immune disorder.