title: Incidence of alloimunization in sickle cell disease: experience of a center in São Paulo.
abstract: OBJECTIVE
  To identify the incidence of alloimmunization in sickle cell disease patients, as well as autoantibodies and the phenotypic profile of these patients for the following erythrocyte antigen groups: Rh, Kell, Kidd, Duffy and MNS.
  
  
  METHODS
  fifty-seven patients were evaluated during follow-up at the Anemia Outpatient Clinic of Irmandade da Santa Casa de São Paulo, where a search for irregular antibodies and phenotyping was carried out.
  
  
  RESULTS
  Patients' median alloimmunization age in sickle cell disease was 25 years, and irregular antibodies were found in 22.6% of them. Anti-Kell antibody was the most frequent (7.5%) followed by anti-C (5.7%).
  
  
  CONCLUSIONS
  The prevalence of alloimmunization and of patients with autoantibodies among individuals with sickle cell disease followed at the Anemia Outpatient Clinic of Irmandade da Santa Casa de Misericórdia de São de Paulo was determined. The risk of alloimmunization was higher in patients who received more than 3 red blood cell units in the past 2 years. The most prevalent alloantibodies were anti-Kell and anti-C.
authors.affiliation: Hospital Israelita Albert Einstein - HIAE, São Paulo, SP, BR.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Helman
authors.affiliation: Faculdade de Ciências Médicas da Santa Casa de São Paulo - FCMSCSP, Sao Paulo, SP, BR.
authors.forename: Rodolfo Delfini
authors.initials: RD
authors.lastname: Cançado
authors.affiliation: Faculdade de Ciências Médicas da Santa Casa de São Paulo - FCMSCSP, Sao Paulo, SP, BR.
authors.forename: Cristina
authors.initials: C
authors.lastname: Olivatto