Abstract:
Thalassemia is the most important anemia disease in Thailand. It is an inherited hematological disease caused by defective production of adult hemoglobin (Hb A). This failure leads to an anemia with different degrees of severity. Even though the disease does not directly affect immune functions, infection, as a major cause of death in thalassemia, is strongly linked to immune response. However, there is not enough information to clearly explain immune functions in thalassemia, which is connected to more and more frequent episodes of both mild and severe infections. Neutrophils, professional phagocytes, play a crucial role as the first line defence against infectious pathogens in an innate immune response. For thalassemia, there are numerous reports of both defective and normal neutrophil functions fromdifferent techniques. Technical reliability has been discussed as a cause of controversial reports. Therefore, a gold standard technique for neutrophil function assessment, such as flow cytometry is required.
In this thesis, a dual color flow cytometry technique was developed for neutrophil function assessment by using whole blood (Wb) specimens. Neutrophils population was distinguished with CD13-PE labeling, while Candida albicans target particles were labeled by BCECF fluorochrome. This developed technique showed significant correlation when compared to standard dextran technique (Dx) (R2>0.99). When applied for assessment of neutrophil opsonophagocytosis and killing functions of patients with splenectomized thalassemia/Hb E (n=20), nonsplenectomized thalassemia/Hb E (n=20), and Hb H disease (n=20) it was found that thalassemia neutrophil functions were normal at 10, 30, and 60 minutes of incubation periods when compared to healthy donors (n=20). Opsonophagocytosis and killing functions showed significant exponential correlation (R2>0.99), while splenectomy, iron overload, and other hematological parameters showed no significant relation to neutrophil functions.
Flow cytometric assessment of neutrophils using whole blood specimens is rapid, simple, and reproducible. It not only mimics the physical properties of peripheral blood, but also reduces time consumption and preserves neutrophil functions. Morover, only small amounts of whole blood are required, thus it is applicable for neutrophil function assessment in newborn or animal models with thalassemia and other diseases