In conclusion, the CSF peptide profile of the control samples differed from both MScl types, with, not unexpectedly, proteins related to immune response showing the highest fold increase in abundance in the MScl types compared to the controls. Even though the CSF peptide profiles measured by MALDI-FT-ICR of PP MScl and RR MScl were quite similar, still a few differences could be observed, most notably regarding the molecules confirmed by immunoassay, protein jagged-1 and vitamin Dbinding protein. Author Contributions Interstitial lung diseases in children Interstitial lung disease (ILD) in infants and children comprises a large spectrum of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. These disorders are characterized by inflammatory and fibrotic changes that affect alveolar walls. Typical features of ILD include dyspnea, diffuse infiltrates on chest radiographs, and abnormal pulmonary function tests with restrictive ventilatory defect and/or impaired gas exchange. Many pathological situations can impair gas exchange and, therefore, may contribute to progressive lung damage and ILD. Consequently, diagnosis approach needs to be structured with a clinical evaluation requiring a careful history paying attention to exposures and systemic diseases. Several classifications for ILD have been proposed but none is entirely satisfactory especially in children. The present article reviews current concepts of pathophysiological mechanisms, etiology and diagnostic approaches, as well as therapeutic strategies. The following diagnostic grouping is used to discuss the various causes of pediatric ILD: 1) exposure-related ILD; 2) systemic disease-associated ILD; 3) alveolar structure disorder-associated ILD; and 4) ILD specific to infancy. Therapeutic options include mainly anti-inflammatory, immunosuppressive, and/or anti-fibrotic drugs. The outcome is highly variable with a mortality rate around 15%. An overall favorable response to corticosteroid therapy is observed in around 50% of cases, often associated with sequelae such as limited exercise tolerance or the need for long-term oxygen therapy. Interstitial lung disease (ILD) in infants and children represents a heterogeneous group of respiratory disorders that are mostly chronic and associated with high morbidity and mortality (around 15%) [1, 2] . These disorders are characterized by inflammatory and fibrotic changes that affect alveolar walls. Typical features of ILD include the presence of diffuse infiltrates on chest radiograph, and abnormal pulmonary function tests with evidence of a restrictive ventilatory defect (in older children) and/or impaired gas exchange [3] .