Whole Lung Lavage Treatment of Chinese Patients with Autoimmune Pulmonary Alveolar Proteinosis: A Retrospective Long-term Follow-up Study

BACKGROUND Pulmonary alveolar proteinosis (PAP) is a rare lung disease, the most common type of which is autoimmune PAP. The gold standard therapy for PAP is whole lung lavage (WLL). Few studies have reported the optimal technique with which to evaluate the response to WLL. In this study, we aimed to identify parameters with which to assess the need for repeat WLL during a long-term 8-year follow-up. METHODS We conducted a retrospective analysis of 120 patients with autoimmune PAP with 80 of whom underwent WLL. Physiologic, serologic, and radiologic features of the patients were analyzed during an 8-year follow-up after the first WLL treatment. RESULTS Of the 40 patients without any intervention, 39 patients either achieved remission or remained stable and only one died of pulmonary infection. Of the 56 patients who underwent WLL for 1 time, 55 remained free from a second WLL and 1 patient died of cancer. Twenty-four required additional treatments after their first WLL. The baseline PaO 2 (P = 0.000), PA-aO 2 (P = 0.000), shunt fraction rate (P = 0.001), percent of predicted normal diffusing capacity of the lung for carbon monoxide (DLCO%Pred) (P = 0.016), 6-min walk test (P = 0.013), carcinoembryonic antigen (CEA) (P = 0.007), and neuron-specific enolase (NSE) (P = 0.003) showed significant differences among the three groups. The need for a second WLL was significantly associated with PaO 2 (P = 0.000), CEA (P = 0.050) , the 6-minute walk test (P = 0.026), and DLCO%Pred (P = 0.041). The DLCO%Pred on admission with a cut-off value of 42.1% (P = 0.001) may help to distinguish whether patients with PAP require a second WLL. CONCLUSIONS WLL is the optimal treatment method for PAP and provides remarkable improvements for affected patients. The DLCO%Pred on admission with a cut-off value of 42.1% may distinguish whether patients with PAP require a second WLL.