title: Idiopathic pleuroparenchymal fibroelastosis is characterized by an elevated serum level of surfactant protein-D, but Not Krebs von den Lungen-6.
abstract: OBJECTIVE
  Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a recently reported rare disease entity characterized by fibrotic thickening of the pleural and subpleural parenchyma predominantly in the upper lobes in idiopathic interstitial pneumonias (IIPs). Because the clinical features of this rare disease are not fully elucidated, we examined the clinical characteristics of IPPFE, especially for serum interstitial biomarkers, surfactant protein-D (SP-D), and Krebs von den Lungen-6 (KL-6).
  
  
  RESULTS
  Four consecutive cases of IPPFE who fulfilled the diagnostic criteria were studied. All cases were more than 60 years of age, and were classified as underweight by body mass index. A severe restrictive ventilatory defect was found in all cases on admission. High-resolution computed tomography showed intense pleural thickening associated with fibrosis predominant in upper lobes. Histopathological findings were also confirmed in three out of four cases. Interestingly, the serum level of SP-D was markedly elevated in all cases, while KL-6 was within normal range in three out of four cases. As compared with major IIPs such as idiopathic pulmonary fibrosis and fibrotic nonspecific interstitial pneumonia, IPPFE significantly showed higher frequency of cases with a unique pattern of serum biomarkers, which is characterized by an elevated level of SP-D with a normal range of KL-6.
  
  
  CONCLUSIONS
  In IPPFE, SP-D might tend to be elevated, while KL-6 was within a normal range. Further study is required to determine the pathogenesis and clinical significance of the elevated SP-D in IPPFE.
authors.affiliation: Department of Respiratory Medicine and Rheumatology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Seidai
authors.initials: S
authors.lastname: Sato
authors.forename: Masaki
authors.initials: M
authors.lastname: Hanibuchi
authors.forename: Asami
authors.initials: A
authors.lastname: Fukuya
authors.forename: Youhei
authors.initials: Y
authors.lastname: Yabuki
authors.forename: Hiroki
authors.initials: H
authors.lastname: Bando
authors.forename: Terumi
authors.initials: T
authors.lastname: Yoshijima
authors.forename: Hisatsugu
authors.initials: H
authors.lastname: Goto
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Ogawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nishioka
mesh_terms: D000368:Aged; D001344:Autopsy; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D017809:Fatal Outcome; D006801:Humans; D054988:Idiopathic Interstitial Pneumonias / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000097:blood*; D010995:Pleural Diseases / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D012123:Pulmonary Ventilation; D012189:Retrospective Studies; D013147:Spirometry; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C060192:MUC1 protein, human; D018396:Mucin-1; D037663:Pulmonary Surfactant-Associated Protein D