Reference Interval
Negative
Interpretive Data
Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes the proliferation and differentiation of hematopoetic cells including macrophages, neutrophils and dendritic cells. Neutralization of GM-CSF activity can therefore impair the development and/or function of these cell types.
Neutralizing anti-GM-CSF autoantibodies are associated with pulmonary alveolar proteinosis (PAP), a rare lung disease that is characterized by the inability of macrophages to clear surfactant from the alveolar lung spaces. Additionally, anti-GM-CSF autoantibodies have been noted in patients with opportunistic infections with intracellular organisms such as M. avium complex, Cryptococcus, Nocardia and Aspergillus species. It is possible that neutralization of GM-CSF in vivo leads to compromised macrophage function which is a key component of the immune response to intracellular organisms.
Anti-GM-CSF autoantibodies are detected by an initial screening ELISA. If the result is positive, the test reflexes to a flow cytometry assay to determine the ability of the autoantibody to neutralize GM-CSF. Low titer, non-neutralizing autoantibodies may be detected in healthy individuals. Clinically significant anti-GM-CSF autoantibodies are reported when both the ELISA and the abilty to neutralize GM-CSF are positive.
References:
Kitamura, T., et al. Idiopathic pulmonary alveolar proteinosis as an autoimmune disease with neutralizing antibody against granulocyte/macrophage colony-stimulating factor. The Journal of experimental medicine. 1999; 190:875-880.
Bonfield, T. L., et al. Anti-GM-CSF titer predicts response to GM-CSF therapy in pulmonary alveolar proteinosis. Clinical Immunology. 2002; 105:342-350.
Rosen, L. B., et al. Anti-GM-CSF autoantibodies in patients with cryptococcal meningitis. Journal of Immunology. 2013; 190:3959-3966