Prevalence of Allo and Auto Antibodies in Adults with SCD

Allo- and auto- antibody formation is one of the major and serious complications of RBC transfusion in patients with sickle cell disease. This problem appears to be more common than in other diseases requiring chronic transfusion that leads to acute and delayed hemolytic transfusion reactions, serious morbidity and occasional life threatening problems. Although there have been reports describing prevalence of immunization in SCD patients, data specific for adult population with SCD is lacking. We report the prevalence of allo- and auto-immunization in adult SCD patients.

Patients aged 18 and above with diagnoses of SCD, confirmed by standard hemoglobin electrophoresis, who had at least one type and cross match done from 1995 through 2011 were considered eligible. To facilitate patient management all data on antibody identification, screening and transfusions were routinely recorded in the electronic database of the Georgia Comprehensive Sickle Cell Program at Grady Health System. We gathered red cell antigen phenotype, dates and results of antibody screens, antibody specificity, and demographics which include but not limited to age in years and gender of all transfused patients.

A total of 424 patients 230 females and 194 males were identified with SCD who have been tested for antibodies during this period. The average age of the patients is 34 (range 18–84). A total of 138/32.5% of patients had antibodies. The most common antibodies were E (14%), C (10%) and K (8%). This may be an under estimations because antibodies disappear over time without repeated exposure. A total of 82 (19.3%) of patients developed autoantibodies. Detailed results described in Table 1.

Allo and auto antibody formation remains significant limiting factor in finding compatible blood resulting in delays in availability of blood for transfusion that can compromise patient care in SCD. With better supportive care and hydroxyurea, adult population is growing resulting in increased need for blood transfusion and risk of antibody formation. Our practice is to do limited phenotypic matching in all patients and extended phenotype matching once antibodies are produced. Despite this practice allo- and autoimmunization continues to be a significant problem. Studies need to be done to understand pathophysiology of antibody formation in SCD and prospective randomized trials are required to define best preventive clinical practices.

No relevant conflicts of interest to declare.