title: Secondary pulmonary alveolar proteinosis complicating myelodysplastic syndrome results in worsening of prognosis: a retrospective cohort study in Japan.
abstract: BACKGROUND
  Secondary pulmonary alveolar proteinosis (sPAP) is a very rare lung disorder comprising approximately 10% of cases of acquired PAP. Hematological disorders are the most common underlying conditions of sPAP, of which 74% of cases demonstrate myelodysplastic syndrome (MDS). However, the impact of sPAP on the prognosis of underlying MDS remains unknown. The purpose of this study was to evaluate whether development of sPAP worsens the prognosis of MDS.
  
  
  METHODS
  Thirty-one cases of sPAP and underlying MDS were retrospectively classified into mild and severe cases consisting of very low-/low-risk groups and intermediate-/high-/very high-risk groups at the time of diagnosis of MDS, according to the prognostic scoring system based on the World Health Organization classification. Next, we compared the characteristics, disease duration, cumulative survival, and prognostic factors of the groups.
  
  
  RESULTS
  In contrast to previous reports on the prognosis of MDS, we found that the cumulative survival probability for mild MDS patients was similar to that in severe MDS patients. This is likely due to the poor prognosis of patients with mild MDS, whose 2-year survival rate was 46.2%. Notably, 75% and 62.5% of patients who died developed fatal infectious diseases and exacerbation of PAP, respectively, suggesting that the progression of PAP per se and/or PAP-associated infection contributed to poor prognosis. The use of corticosteroid therapy and a diffusing capacity of the lung for carbon monoxide of less than 44% were predictive of poor prognosis.
  
  
  CONCLUSIONS
  Development of sPAP during the course of MDS may be an important adverse risk factor in prognosis of patients with mild MDS.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Ishii
authors.forename: John F
authors.initials: JF
authors.lastname: Seymour
authors.forename: Ryushi
authors.initials: R
authors.lastname: Tazawa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Inoue
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Uchida
authors.forename: Aya
authors.initials: A
authors.lastname: Nishida
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Kogure
authors.forename: Takeshi
authors.initials: T
authors.lastname: Saraya
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tomii
authors.forename: Toshinori
authors.initials: T
authors.lastname: Takada
authors.forename: Yuko
authors.initials: Y
authors.lastname: Itoh
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hojo
authors.forename: Toshio
authors.initials: T
authors.lastname: Ichiwata
authors.forename: Hajime
authors.initials: H
authors.lastname: Goto
authors.affiliation: Bioscience Medical Research Center, Niigata University Medical & Dental Hospital, 1-754 Asahimachi-dori, Chuo-ku, Niigata 9518520, Japan. radical@med.niigata-u.ac.jp.
authors.forename: Koh
authors.initials: K
authors.lastname: Nakata
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications*; D011379:Prognosis; D011649:Pulmonary Alveolar Proteinosis / Q000209:etiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index