Diffuse Pulmonary Non-Amyloid Light-Chain Deposition Disease: Phenotypes and Outcome

Abstract

Diffuse pulmonary light chain deposition disease (LCDD) is a rare lung disorder due to deposition of immunoglobulin light chains along the basement membranes of the alveolar, bronchial and vascular walls. Data on patients’ characteristics, disease course and prognosis are limited with only few patients reported. We conducted a multicenter retrospective cohort study on patients with pulmonary LCDD to evaluate patients’ demographics, characteristics at baseline and prognosis. Patients’ data on clinical, laboratory, functional characteristics, and outcome were collected. Imaging was reviewed by three radiologists. Only patients with histological confirmation were considered eligible. We identified 31 cases, characterized by a female predominance (68%) and a median age at presentation of 50 years. Baseline pulmonary function test showed obstructive pattern in 45 % of patients. Chest CT revealed lung cysts in 92 % and cystic bronchiectasis in 69 % of cases. Serum Kappa light chain was elevated in 83 % of patients. Median follow-up duration was 6 years. Median annual decline in FEV1 and Dlco were 127 ml and 4.3%, respectively. Histologic analysis showed monotypic Kappa light chain deposits in all but one patients, and lambda in one. Half of patients received immunomodulatory treatment or chemotherapy targeting reduction of plasma light chains. Serum K light chain level decreased in 9 cases, but FEV1 continued to decline. Out of 31 patients, 15 underwent bilateral lung transplantation. Transplant free survival was 70 % and 30 % at 5 years and 10 years, respectively.