 The purpose of this study is to 1 compare a technically improved assay with an existing assay used to measure serum anti-GM-CSF antibodies in stored serum samples previously obtained from patients diagnosed with either primary, secondary, congenital or idiopathic pulmonary alveolar proteinosis PAP, other chronic diseases or disease-free, healthy individuals; 2 determine the prevalence and levels of anti-GM-CSF autoantibodies and 3 define the breadth of the autoimmune antibody responses in primary PAP patients from the United States, Japan, Australia, and Europe using previously collected serum samples; and 4 using a chart review approach, compare the clinical, radiologic and laboratory features of primary PAP patients to determine if differences exist among patients in these globally geographically distributed regions. 