Contributions
Abstract: PB1820
Type: Publication Only
Session title: Thalassemias
Background
It is suggested that alloimmunization develops due to erythrocyte antigen differences between the blood donor and the recipient, the immune status of the recipient and the immune modulatory effects of repeated allogeneic blood transfusions on the immune system of the recipient. Understanding the immune regulators responsible for alloantibody development in transfusion dependent thalassemia patients will provide appropriate data for the reduction and / or prevention of alloimmunization rate.
Aims
We aimed to evaluate the association of alloimmunization and basic immune functions in transfusion-dependent thalassemia patients.
Methods
Fifty-four patients with a diagnosis of transfusion-dependent thalassemia between the ages of 1-24 who were regularly monitored in the Thalassemia Unit were retrospectively evaluated. In these patients, the frequency and types of alloantibodies and the basic immune functions tests and demographic characteristics that affect their formation were examined.
Results
The rate of alloantibody detection was 29.6%, and clinical alloimmunization was detected in 24% of the patients. The most common type of alloantibody is against the Rhesus system (70%) and secondly against the Kell system (23%) and Lutherian system (7%).
When the relationship between regular transfusion initiation age and development of alloantibody was examined; it is found out that while in 38 patients without alloantibody development the median age was 11.5 months (4-32 months), in 16 patients with alloantibody development the median age was 15 months (6-54 months). The age of initiation of regular transfusion was statistically significantly late in patients with alloantibody development (p=0.03). The frequency of transfusion between the groups was compared, and it was found that due to development of alloantibody, the need for transfusion, and therefore, more frequent transfusions increased significantly (p<0.001). Direct coombs positivity was detected in 8 (50%) of 16 patients with alloantibody development. Direct coombs was found positive in 5 (13.2%) of 38 patients without alloantibody development, and a statistically significant relationship was found between alloantibody development and direct coombs positivity (p=0.01). The 5 patients without alloantibody development but with direct coombs positivity mentioned here are patients with splenectomy.
No significant difference was found between the groups in terms of IgG, IgA, and IgM values (p=0.403, p=0.747, p=0.272). Similarly, there is no statistical significance between C3 level and development of alloantibody (p=1.00). Serum C4 levels were found to be low in 8 (14.8%) of 54 patients, 6 of these 8 patients were found to be alloantibody positive. There was no significant difference between the total lymphocyte count, CD3+, CD4+, CD8+, and NK cells in the two groups whose lymphocyte panel results were evaluated (p=0.270, p=0.291, p=0.05, p=1.00, p=0.483). However, CD19+ B cells were lower in the alloantibody present group (p=0.02). In addition, serum C4 level was found to be statistically significantly lower in patients with alloantibody development (p=0.006).
Conclusion
In this study, we found a strong relationship between alloantibody development and D. coombs positivity, low C4 and low CD19+ B cell numbers.We believe that studies at molecular level should be increased and studies should be conducted with a larger number of patients in order to elucidate the immune pathogenesis of alloimmunization and determine the markers that will enable early recognition.
Keyword(s): ABO blood group, Immunity, Thalassemia
Abstract: PB1820
Type: Publication Only
Session title: Thalassemias
Background
It is suggested that alloimmunization develops due to erythrocyte antigen differences between the blood donor and the recipient, the immune status of the recipient and the immune modulatory effects of repeated allogeneic blood transfusions on the immune system of the recipient. Understanding the immune regulators responsible for alloantibody development in transfusion dependent thalassemia patients will provide appropriate data for the reduction and / or prevention of alloimmunization rate.
Aims
We aimed to evaluate the association of alloimmunization and basic immune functions in transfusion-dependent thalassemia patients.
Methods
Fifty-four patients with a diagnosis of transfusion-dependent thalassemia between the ages of 1-24 who were regularly monitored in the Thalassemia Unit were retrospectively evaluated. In these patients, the frequency and types of alloantibodies and the basic immune functions tests and demographic characteristics that affect their formation were examined.
Results
The rate of alloantibody detection was 29.6%, and clinical alloimmunization was detected in 24% of the patients. The most common type of alloantibody is against the Rhesus system (70%) and secondly against the Kell system (23%) and Lutherian system (7%).
When the relationship between regular transfusion initiation age and development of alloantibody was examined; it is found out that while in 38 patients without alloantibody development the median age was 11.5 months (4-32 months), in 16 patients with alloantibody development the median age was 15 months (6-54 months). The age of initiation of regular transfusion was statistically significantly late in patients with alloantibody development (p=0.03). The frequency of transfusion between the groups was compared, and it was found that due to development of alloantibody, the need for transfusion, and therefore, more frequent transfusions increased significantly (p<0.001). Direct coombs positivity was detected in 8 (50%) of 16 patients with alloantibody development. Direct coombs was found positive in 5 (13.2%) of 38 patients without alloantibody development, and a statistically significant relationship was found between alloantibody development and direct coombs positivity (p=0.01). The 5 patients without alloantibody development but with direct coombs positivity mentioned here are patients with splenectomy.
No significant difference was found between the groups in terms of IgG, IgA, and IgM values (p=0.403, p=0.747, p=0.272). Similarly, there is no statistical significance between C3 level and development of alloantibody (p=1.00). Serum C4 levels were found to be low in 8 (14.8%) of 54 patients, 6 of these 8 patients were found to be alloantibody positive. There was no significant difference between the total lymphocyte count, CD3+, CD4+, CD8+, and NK cells in the two groups whose lymphocyte panel results were evaluated (p=0.270, p=0.291, p=0.05, p=1.00, p=0.483). However, CD19+ B cells were lower in the alloantibody present group (p=0.02). In addition, serum C4 level was found to be statistically significantly lower in patients with alloantibody development (p=0.006).
Conclusion
In this study, we found a strong relationship between alloantibody development and D. coombs positivity, low C4 and low CD19+ B cell numbers.We believe that studies at molecular level should be increased and studies should be conducted with a larger number of patients in order to elucidate the immune pathogenesis of alloimmunization and determine the markers that will enable early recognition.
Keyword(s): ABO blood group, Immunity, Thalassemia