Background: Hypogammaglobulinemia (HGG) frequently occurs after solid organ transplantation; however, the prevalence and implications of HGG after lung transplantation are not well defined. The authors aimed to define the prevalence, risk factors, and outcomes of patients with severe HGG after lung transplantation. METHODS.: The authors performed a retrospective cohort study of 57 lung transplant recipients at their center. Quantitative total and subclass immunoglobulin (Ig) G levels were obtained from patients.
Results: Thirty-four (60%; 95% confidence interval [CI], 46%-72%) patients had low IgG levels (IgG <700 mg/dL); of these, eight (14%; 95% CI, 6%-26%) had severe HGG (IgG <400 mg/dL). Female patients had a higher risk of severe HGG than male patients (25% vs. 0%, P=0.007), and patients who underwent transplantation for emphysema had a higher risk of severe HGG than others (P=0.04). Patients with bronchiolitis obliterans syndrome had a higher risk of severe HGG than those without (50% vs. 10%, P=0.03). Severe HGG was associated with an increased risk of pneumonia (P=0.01) and worse survival (P=0.04) but with neither the incidence of cytomegalovirus disease (P=0.54) nor a subsequent diagnosis of bronchiolitis obliterans syndrome (P=0.70).
Conclusions: The authors have documented a high prevalence of HGG after lung transplantation. Emphysema, female gender, and bronchiolitis obliterans syndrome are risk factors for severe HGG. Patients with severe HGG had a higher cumulative incidence of pneumonia and worse survival. Studies of the efficacy and safety of IgG supplementation after lung transplantation should be pursued.