Red Blood Cell Immunization and Contributing Factors in 685 Thalassemia Patients

Background: An analysis of red blood cell alloimmunization in patients with thalassemia can help to devise specific strategies to decrease the alloimmunization rate. This study explored the frequency and specificity of alloantibodies and autoantibodies against red blood cell (RBC) antigens in patients with thalassemia referring to the Iranian Blood Transfusion Organization (IBTO) Immunohematology Reference Laboratory (IRL) in Tehran.

Materials and Methods: This study first examined the laboratory records of 23,113 patients suffering from different diseases referring to IBTO’s IRL for pretransfusion testing in the 2008-2015 period. ABO and Rh(D) typing and antibody screening tests were performed for all 23,113 patient records and 685 (2.97%) beta-thalassemia patients with positive pre-transfusion test results (antibody screening and/or DAT) were selected for further investigation.

Results: The antibody screening test was positive in 640 out of 685 thalassemic patients (93.4%). DAT was performed for 529 patients, 226 (33%) of which showed positive results. Meanwhile, 161 out of 685 beta-thalassemia patients (23.5%) had positive auto control test results, reflecting the possible presence of allo- and/or autoantibodies. The most common antigen-specific alloantibodies were directed against K and E RBC antigens with a frequency of 25% (Anti-K) and 11.91% (Anti-E), respectively. The development of two antibodies (double antibodies) in one patient was observed in 80 individuals (11.46%).

Conclusion: Age, gender, history of pregnancy, and splenectomy were not contributing factors to the antibody presence in the patient population under study. Extended red blood cell phenotyping should be considered as an essential procedure for expected multi-transfused thalassemia patients before blood transfusion. Considering the high frequency of anti-K and anti-E observed in this study, it is recommended that thalassemia patients in Iran are tested through phenotyping of RBC units for K and E antigens before transfusion.

Preparation, purification and virus inactivation of intravenous immunoglobulin from human plasma

IVIG can be prepared from fractionation of normal human plasma and it is used as a therapeutic drug for treatment of various diseases. IVIG has been for some time the high-growth product within the plasma derived products, at both a global and a national country level. Fractionation was performed according to Cohn method with some modifications. Fraction II was first produced and then it was used for purification and virus inactivation steps. Two methods of virus inactivation (pasteurization at 60 degrees C for 10 hours and solvent/detergent treatment with TnBP and Tween 80) were used and validated. A chromatography method (cation exchange chromatography on CM Sepharose FF) was also added to obtain high purity. The final product (in liquid and freeze dried formulation) meets European Pharmacopeias requirements. The amount of PKA and aggregates was beyond the acceptance limit. The intactness of the IVIG was also examined by circular dichroism (secondary and tertiary structure). It was stable after 6 months of storage. Since Iran market is completely dependant on importation of plasma derived products, it is important to develop such methods for production of IVIG to obtain regional demands.

Inactivation of virus in intravenous immunoglobulin G using solvent/detergent treatment and pasteurization

The safety of plasma derived medicinal products, such as immunoglobulin, depends on viral inactivation steps that are incorporated into the production process. Several attempts have been made to validate the effectiveness of these inactivation methods against a range of physio-chemically diverse viruses. Treatment with solvent/detergent (S/D) and pasteurization (P) has been continuously used in our IgG production and these methods were analysed in this study as models of viral inactivation. Bovine Viral Diarrhoea Virus (BVDV), Herpes Simplex Virus (HSV) and Vesicular Stomatitis Virus (VSV) were employed as models of HCV, HBV and HIV respectively. Polio and Reo viruses also were used as stable viruses to chemical substances. The infectivity of a range of viruses before and after treatment with two methods of viral inactivation was measured by end point titration and their effectiveness expressed as Logarithmic Reduction Factors (LRF). Solvent/detergent treatment reduced the amount of enveloped viruses by 5-6 logs. The reduction factor was between 5-6 logs for all viruses used in the pasteurization process. A final log reduction factor was obtained as the sum of the two individual methods. Both inactivation methods have advantages and disadvantages with respect to their ability to inactivate viruses. Thus,combination of two robust virus inactivation steps, solvent/detergent and pasteurization, increases the safety margin of immunoglobulin preparations.

Evaluation of the homing of human CD34+ cells in mouse bone marrow using clinical MR imaging

There have been several reports using various superparamagnetic iron oxide (SPIO) nanoparticles to label mammalian cells for monitoring their temporal and spatial migration in vivo by Magnetic Resonance Imaging (MRI). The purpose of this study was to evaluate the efficiency of labeling cells using two commercially available FDA-approved agents: ferumoxide, a suspension of dextran-coated SPIO used as an MRI contrast agent and protamine sulfate used ex vivo as a cationic transfection agent to evaluate the use of clinical 1.5 Tesla magnetic resonance imaging equipment in showing the in vivo homing of iron oxide-labeled human CD34+ cells in irradiated mouse. After labeling human Hematopoietic (CD34+) stem cells with ferumoxide-protamine sulfate complex (FE-Pro), cellular toxicity, functional capacity and quantitative cellular iron incorporation were determined. FE-Pro labeled cells demonstrated neither short or long-term toxicity nor changes in colonogenic assay of the stem cells and their phenotype when compared with unlabeled cells. Efficient labeling with FE-Pro was observed with iron content per cell varying between 1.91 +/- 0.1 pg for CD34+ cells with 100% of cells labeled. After irradiation, Female Balb/c mice underwent MR imaging before and 12, 24, 48 and 72 h after intravenous injection of 0.5-1.5 x 10(7) labeled CD34+ cells. A significant decrease in MR signal intensity was observed in bone marrow at 24 and 48 h after injection. Our observations confirm that efficient labeling of cells with appropriate contrast agents should facilitate the translation of this method to clinical trials for evaluating the trafficking of infused or transplanted cells by MR Imaging.

Generation of IL-8 and TNF-alpha in platelet concentrates during storage

BACKGROUND

Platelet transfusion is accompanied by febrile nonhemolytic transfusion reactions. The generation of cytokines (like IL-1 beta, IL-6, IL-8, and TNF-alpha) in platelet concentrates by white cells is suggested to be responsible for febrile nonhemolytic transfusion reactions. The number of white cells in the platelet concentrates is crucial to cytokine generation.

METHODS

This study was performed to determine whether WBC reduction in platelet concentrates by prestorage leukodepletion filters or inactivation by gamma radiation reduced the levels of these cytokines during storage for 3 days. Each of the platelet concentrates (n = 54) was prepared from a single random donor by platelet-rich plasma. This was then divided into four groups: 1) unfiltered, nonirradiated random-donner platelet concentrates (n = 13); 2) unfiltered, gamma-irradiated random-donner platelet concentrates (n = 16); 3) filtered, nonirradiated random-donner platelet concentrates (n = 14); and 4) filtered, gamma-irradiated random-donner platelet concentrates (n = 11). Cytokine levels in platelet concentrates supernatants were measured by ELISA kits according to the manufacturer's recommendations.

RESULTS

Our results showed that IL-8 was detected in unfiltered, nonirradiated, and gamma-irradiated random-donner platelet concentrates but not in the filtered random-donner platelet concentrates. TNF-alpha was only detected in unfiltered, nonirradiated units. Compared with unfiltered platelet concentrates, prestorage filtration prevented a rise in the IL-8 and TNF-alpha on day 3 of storage. The concentration of IL-1 beta was lower than the minimum concentration value of the kit used for this purpose. IL-6 was detected only in 7 units of all filtered platelet concentrates on day 3.

CONCLUSION

These data indicate that gamma irradiation can not prevent generation of IL-8 in platelet concentrates during storage, but prestorage leukoreduction of platelet concentrates can prevent accumulation of IL-6, IL-8, and TNF-alpha during storage.