We performed the ELFTM test (Siemens), which provides a score of fibrosis based on quantitative measurements of hyaluronic acid (HA), amino-terminal propeptide of type III procollagen (PIIINP), and tissue inhibitor of metalloproteinase 1 (TIMP-1) from serum of 21 aPAP patients, collected at diagnosis. The gene discussed is TIMP1; the disease is autoimmune pulmonary alveolar proteinosis.