The impact of allogeneic hematopoietic stem cell transplantation on pulmonary complications in adults with inborn errors of immunity.

Abstract

Pulmonary involvement (repeated lung infections, lung parenchymal inflammation, scarring, and malignancies) is frequent in patients with inborn errors of immunity (IEIs) and accounts for a significant proportion of the disease burden. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can cure most severe IEIs. The indications for allo-HSCT have recently been extended to adults. We sought to assess the impact of allo-HSCT specifically on respiratory status. We retrospectively analyzed data of 50 patients with IEIs who underwent a first allo-HSCT after the age of 16 at 3 expert centers in France. The median length of follow-up was 4.8 years (interquartile range: 1.6-9.2) before allo-HSCT and 3 years (interquartile range: 1.4-6.0) after allo-HSCT. Ten patients died as a result of allo-HSCT-related complications. Four patients developed bronchiolitis obliterans syndrome. After 1-year posttransplantation, the mean annualized rate of severe respiratory infections (0.14 [95% CI: 0.04 to 0.24]) was lower than the value recorded before transplantation (0.54 [95% CI: 0.25 to 0.82]; P = .003 for paired comparisons of equivalent durations). Lung function was declining before allo-HSCT (mean FEV₁: -2.09% predicted/year [95% CI: -7.27 to 3.09]) but increased afterward (+2.44% predicted/year [95% CI: -4.79 to 9.69], P = .0034 for paired comparisons). On computed tomography scans of the chest, bronchial disorders and lung parenchyma cavities were the most frequent abnormal findings. The bronchial thickening and bronchiolar micronodules regressed after allo-HSCT, whereas bronchiectasis and residual parenchymal cavities were stable. allo-HSCT seems likely to protect the long-term pulmonary prognosis of adults with IEIs; it is associated with a significantly lower incidence of severe respiratory infections, better lung function, and radiologic stabilization of lung damage.