title: [Changes of the complement system in myelodysplastic syndromes].
abstract: OBJECTIVE
  To search complement system activity and detection of circulating immune complexes in a group of patients with myelodysplastic syndromes (MDS) classified as with relatively favourable and unfavourable prognosis.
  
  
  METHODS
  28 patients with MDS were examined, 12 with refractory anaemia and 4 with refractory ringed sideroblastic anaemia, both subgroups of relatively favourable prognosis; 9 patients with refractory anaemia with blastic excess and 3 with refractory anaemia with blastic excess in transformation, subgroups of unfavourable prognosis. We determined factor B, alternate and classical hemolytic activity, as well as C3 and C4 quantification of the complement system. Circulating immune complexes detection was performed by the C1q deviation test and polyethylene glycol 6000 precipitation method at 3.75% final concentration.
  
  
  RESULTS
  A significant decrease in C3 level, alternate haemolytic activity and factor B was demonstrated in the unfavourable prognosis subgroups in comparison with patients of favourable prognosis and normal controls.
  
  
  CONCLUSIONS
  Our results suggest the possibility of subclinical infections in patients with unfavourable prognosis.
authors.affiliation: Instituto de Hematología e Inmunología, Ciudad de La Habana, Cuba.
authors.forename: R
authors.initials: R
authors.lastname: Villaescusa Blanco
authors.forename: A A
authors.initials: AA
authors.lastname: Arce
authors.forename: R M
authors.initials: RM
authors.lastname: Santos
authors.forename: N
authors.initials: N
authors.lastname: Fernández
mesh_terms: D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000097:blood*; D003167:Complement Activation; D003176:Complement C3 / Q000032:analysis / Q000172:deficiency; D003181:Complement C4 / Q000032:analysis; D011415:Complement Factor B / Q000032:analysis; D003165:Complement System Proteins / Q000502:physiology*; D005260:Female; D006461:Hemolysis; D006801:Humans; D007239:Infections / Q000150:complications; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000097:blood* / Q000145:classification / Q000150:complications / Q000276:immunology / Q000401:mortality; D011379:Prognosis
chemical_list: D000936:Antigen-Antibody Complex; D003176:Complement C3; D003181:Complement C4; D003165:Complement System Proteins; D011415:Complement Factor B