Risk Factors for Allo-immunization in Sickle Cell Disease

Study Overview
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Brief Summary
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Sickle cell patients have a high prevalence of alloimmunization. This high rate of alloimmunization can be partially explained by the existence of an antigenic difference between the predominantly Caucasian donor population and the sickle cell patients of African origin. Genetic and environmental risk factors have also been described. The main risk factors that have been shown in retrospective or cross-sectional studies are some HLA alleles, the age of the patient, the number of leukocyte-depleted erythrocyte concentrates (CED) transfused, the number of transfusion episodes, the age of the CEDs, the existence of an inflammatory event at the time of transfusion and the presence of anti-erythrocyte autoantibodies.There is also evidence of an impaired TH response but the underlying immunological mechanism is not fully understood. The aim of this study is to study the prevalence and the risk factors for anti-erythrocyte alloimmunization in pediatric and adult patients with Sickle Cell Disease (with a SS genotype) who are being followed at Queen Fabiola University Children's Hospital (HUDERF) and at the CHU Brugmann Hospital. The identification of risk factors would allow the investigators to improve, or at least adapt, their transfusion policy to certain clinical or immuno-haematological situations.

Official Title
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Retrospective Study of the Risk Factors for Allo-immunization in Sickle Cell Disease

Conditions
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Sickle Cell Disease

Intervention / Treatment
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* Other: Medical file data collection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Sickle cell disease patients (HbSS genotype) with a history of blood transfusions within the CHU Brugmann and the Queen Fabiola University Hospitals. Exclusion Criteria: - None
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sickle cell disease patients (SS genotype)<br>Sickle cell disease patients with a SS genotype having an history of blood transfusions within the CHU Brugmann and the Queen Fabiola Children's Hospitals. | Other: Medical file data collection<br>* The information described in the 'outcome measures' section will be collected from the medical files of the patients.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Date of birth | Date of birth | january 2013-december 2017 | 
| Sex | Sex | january 2013-december 2017 | 
| Blood group | Blood group | january 2013-december 2017 | 
| Extended phenotype | Sickle cell disease extended phenotype | january 2013-december 2017 | 
| Antibodies | Presence/absence of irregular anti-erythrocytes antibodies (RAI) | january 2013-december 2017 | 
| Number of blood transfusions | Number of blood transfusions | january 2013-december 2017 | 
| Number of blood transfusions | Number of blood transfusions | From birth till the first positive RAI test (up to 50 years) | 
| Auto antibodies | Presence/absence of auto anti-erythrocytes antibodies (RAI) | january 2013-december 2017 | 
| Pathology | Medical issue causing the patient to be included in a chronic blood transfusion program | january 2013-december 2017 | 
| Duration of the chronic transfusion program | Duration of the chronic transfusion program | january 2013-december 2017 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sickle cell disease, Allo-immunization