Risk factors for alloimmunization by patients with sickle cell disease

Abstract

Blood transfusion in patients with sickle cell disease (SCD) is limited by the development of alloantibodies to erythrocytes. In the present study, the frequency and risk factors for alloimmunization were determined. Transfusion records and medical charts of 828 SCD patients who had been transfused and followed at the Belo Horizonte Blood Center, Belo Horizonte, MG, Brazil, were retrospectively reviewed. Alloimmunization frequency was 9.9% (95% CI: 7.9 to 11.9%) and 125 alloantibodies were detected, 79% of which belonged to the Rhesus and Kell systems. Female patients developed alloimmunization more frequently (P = 0.03). The median age of the alloimmunized group was 23.3 years, compared to 14.6 years for the non-alloimmunized group (P < 0.0001). Multivariate analyses were applied to the data for 608 hemoglobin (Hb) SS or SC patients whose number of transfusions was recorded accurately. Number of transfusions (P = 0.00006), older age (P = 0.056) and Hb SC (P = 0.02) showed independent statistical associations with alloimmunization. Hb SC patients older than 14 years faced a 2.8-fold higher (95% CI: 1.3 to 6.0) risk of alloimmunization than Hb SS patients. Female Hb SC patients had the highest risk of developing alloantibodies. In patients younger than 14 years, only the number of transfusions was significant. We conclude that an increased risk of alloimmunization was associated with older patients with Hb SC, specially females, even after adjustments were made for the number of transfusions received, the most significant variable.

Incidence of alloimunization in sickle cell disease: experience of a center in São Paulo

“…In the present study, the risk of alloimmunization was associated with the number of blood transfusions, which agreed with the literature (12,(14)(15)(16) . The risk of alloimmunization for patients who received over 30 transfusions was statistically higher than patients who received up to 5 transfusions.…”

“…may show a difference in the risk of alloimmunization for older patients (9)(10)(11) . The higher frequency of alloimmunization found in this study, in comparison to other Brazilian studies, may be due to the fact that here the antibody identifi cation method used was tube and gel centrifugation, increasing diagnostic sensitivity in relation to the studies that used the tube centrifugation method only (12,13) . However, in the present study, alloimmunization rates found were lower than in international studies, which may refl ect higher phenotype compatibility between blood donors and the patients in this population.…”

“…The studies that have lower alloimmunization rates include predominantly pediatric patients. In Brazil, alloimmunization rates are referred as ranging between 3.2 and 20.8% (11,12) . Again, the lower alloimmunization rates were carried out predominantly with children under 15 years of age; in the present study, none of the patients were less than 16, which…”

“…When antibodies were observed, they were identified through a labeled red blood cell panel reaction, using column agglutination methods and gel centrifugation (ID-Diapanel and ID-Diapanel-P, DiaMed AG) (12,13) . After the identification, antibody elution was performed, followed by phenotyping for the following blood systems: Rh, Kell, Kidd, Duffy and MNS, according to the standard blood bank protocol.…”

Red cell alloimmunization in multitransfused patients and multiparous women

“…SCD patients require blood when there is a sickle cell crisis. Murao and Viana [16] observed 9.9% alloimmunization in SCD. Domen and Ramirez [17] have reported low rate (6.1%) of antibody formation in CRF patients undergoing dialysis while a north Indian study [1] reports 9.9% rate of antibody formation in the same category of patients.…”