1 l of the cDNA reaction was used to amplify each cytokine receptor and control gene with specific primers, for 35 cycles. within alveolar spaces, often leading to respiratory failure (1). Three forms of PAP have been described: congenital, secondary, and acquired. Congenital PAP can result from mutations in genes encoding the surfactant proteins B or C, or the common chain (c) of the receptor for GM-CSF (26). Secondary PAP develops in conditions in which there are reduced numbers or functional impairment of pulmonary alveolar macrophages, and has been associated with the inhalation of inorganic dust (silica) or toxic fumes, hematologic malignancies, pharmacologic immunosuppression, certain infections, and impaired c expression (711). Acquired PAP is the most common form, usually occurring in adults, and is caused by neutralizing autoantibodies to GM-CSF (1214). The importance of GM-CSF in the pathogenesis of PAP has been confirmed in humans and mice, wherein GM-CSF signaling is required for pulmonary alveolar macrophage catabolism of surfactant (1217). In addition, mice with a targeted disruption of GM-CSF or c genes developed PAP (1517). Local expression of GM-CSF in the lungs of GM-CSFdeficient mice, or transplantation of bone marrow from normal mice into c-deficient mice, corrected the defective metabolism of surfactant (1819). Furthermore, administration of GM-CSF has been efficacious in some patients with acquired PAP (20). Because the GM-CSFR is composed of a cytokine-binding GM-CSFR chain (GM-CSFR) subunit and the c subunit (21,22), theoretically, deficiency of either subunit should have the potential to result in PAP. We provide the first report that PAP can result from a genetic deficiency of the GM-CSFR. == RESULTS AND DISCUSSION == == Case history == A 4-yr-old female with Turner syndrome and respiratory insufficiency was diagnosed with PAP at age 3. Her past history was significant for respiratory failure caused by respiratory syncytial virus pneumonia in the first month of life, and a diagnosis of reactive airways disease. She presented with respiratory distress and hypoxemia, with a crazy paving pattern on chest imaging. Open lung biopsy revealed alveolar proteinaceous material without alveolar epithelial hyperplasia or chronic interstitial changes, and bronchoalveolar lavage revealed proteineous material and foamy macrophages, all of which are consistent with PAP. Analyses for mutations of the genes Rabbit polyclonal to HYAL2 encoding surfactant proteins B and C and ABCA3 were negative (performed by the Johns Hopkins DNA Diagnostic Laboratory). Her serum GM-CSF concentration measured by ELISA (performed by the University of Michigan Cytokine Reference Laboratory) was 1,573.3 pg/ml (normal = 07.8 pg/ml), and antiGM-CSF antibody concentration measured by ELISA (performed by the Cleveland Clinic Cytokine Biology Laboratory) was 0 ng/ml. Her complete blood count and differential were normal. Worsening respiratory failure was managed intermittently by whole lung saline lavage under arteriovenous extracorporeal membrane oxygenator support, but pulmonary function progressively declined. Treatment with 20 g/kg GM-CSF per day subcutaneously, which may be efficacious in some patients with acquired PAP Bisoctrizole (20), was not beneficial. Given the absence of surfactant gene mutations and antiGM-CSF antibodies, the elevated Bisoctrizole baseline GM-CSF serum levels and the lack of clinical improvement with exogenous GM-CSF administration, and no evidence for other secondary causes of PAP, Bisoctrizole the potential for a defect in the GM-CSFR was investigated. == Lack of GM-CSFR expression and function in the patient’s monocytes == To test the hypothesis that the patient had a defect in GM-CSFR expression, flow cytometry was used to detect GM-CSFR and c on peripheral blood monocytes of the patient, as well.