title: Serum markers in interstitial pneumonia with and without Pneumocystis jirovecii colonization: a prospective study.
abstract: BACKGROUND
  In patients with chronic respiratory disease, Pneumocystis jirovecii (P. jirovecii) colonization is observed, and may influence disease progression and systemic inflammation. Pneumocystis pneumonia causes interstitial changes, so making a diagnosis of PCP in patients who have interstitial pneumonia (IP) with P. jirovecii colonization is sometimes difficult based on radiography.
  
  
  METHODS
  This study investigated the prevalence of P. jirovecii colonization in IP patients and assessed pulmonary injury due to P. jirovecii colonization by measurement of serum markers (KL-6, SP-A, SP-D, and (1-->3) beta-D-glucan (beta-D-glucan)) and the peripheral lymphocyte counts, prospectively. A total of 75 patients with idiopathic pulmonary fibrosis (n = 29), collagen vascular-related interstitial pneumonia (n = 19), chronic bronchitis or pneumonia (n = 20), and Pneumocystis pneumonia (n = 7) were enrolled in this prospective study. P. jirovecii DNA was detected in sputum samples, while serum markers and the lymphocyte count were measured in the peripheral blood.
  
  
  RESULTS
  IP patients (idiopathic pulmonary fibrosis and collagen vascular-related IP) who received oral corticosteroids had a high prevalence of P. jirovecii colonization (23.3%). In IP patients, oral corticosteroid therapy was a significant risk factor for P. jirovecii colonization (P < 0.05). Serum markers did not show differences between IP patients with and without P. jirovecii colonization. The beta-D-glucan level and lymphocyte count differed between patients with Pneumocystis pneumonia or P. jirovecii colonization.
  
  
  CONCLUSIONS
  Serum levels of KL-6, SP-A, SP-D, and beta-D-glucan were not useful for detecting P. jirovecii colonization in IP patients. However, the serum beta-D-glucan level and lymphocyte count were useful for distinguishing P. jirovecii colonization from pneumocystis pneumonia in IP patients.
authors.affiliation: Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Showa-machi, Maebashi Gunma, Japan. yasuos@med.gunma-u.ac.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Noriaki
authors.initials: N
authors.lastname: Sunaga
authors.forename: Kunio
authors.initials: K
authors.lastname: Dobashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Fueki
authors.forename: Naoto
authors.initials: N
authors.lastname: Fueki
authors.forename: Sohei
authors.initials: S
authors.lastname: Makino
authors.forename: Masatomo
authors.initials: M
authors.lastname: Mori
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D045363:Pneumocystis carinii / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000097:blood / Q000175:diagnosis*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D047071:beta-Glucans / Q000097:blood
chemical_list: D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D047071:beta-Glucans