Red cell alloantibodies in beta-thalassaemia major patients' blood referring to the regional blood transfusion center of Tehran, Iran.

Introduction: Thalassemia is associated with a genetic decline in the rate of synthesis of one or more types of natural hemoglobin polypeptide chains. One of the major complications in thalassemia patients is alloimmunization, which is antibody production by the patient against transfused red blood cells (RBCs). These RBCs are unknown by the recipient and the formed antibodies against them are called alloantibodies. This study aimed to evaluate the frequency of alloantibodies against RBCs in beta-thalassemia patients referred to Tehran Regional Blood Transfusion Center. Methods: In this study, antibody screening tests (Dia-cell I, II, and III) were performed on 184 thalassemia patients. An identification test by the Dia panel consisting of 11 different O RBCs groups to examine sera with Dia cells (I, II, or III) was performed. Results: In our study, males and females patients comprised 66 (35.87%) and 118 (64.13%), respectively, of whom 116 (63%) had alloimmunization. In addition, 68 thalassemia subjects (37%) lacked alloantibodies. Among 184 patients with beta-thalassemia major, anti-K (Kell system), anti-D, and anti-E (Rhesus system) had the most abundant alloantibody variants with an incidence of 24 (13%), 11 (5.98%), and 10 (5.4%), respectively. Conclusion: Before RBC transfusion, regular RBC antigen phenotypes, as well as problem-solving of alloantibody production by receiving compatible blood for Kell and RH subgroups, are suggested for all cases of transfusion-derived thalassemia.

Developing a databank for multiple transfusion patients: Rh antigen and phenotype distribution among 3000 regular blood donors in Iran.

BACKGROUND: Rhesus (Rh) blood group system is clinically the most significant protein-based grouping system. The Rh system is of vital importance in blood transfusion, and incompatibility between the donor and recipient leads to alloimmunization. Alloimmunization is commonly seen in multiple-transfusion recipients (e.g. thalassemia patients). There are a few studies about the prevalence of Rh antigens, except for D, in Iran; and regarding the high prevalence of thalassemia in the country, in this study we have determined antigens and phenotypes of the Rh among population of regular blood donors with the aim of developing a detailed Rh databank. MATERIALS AND METHODS: This cross-sectional study randomly enrolled 3000 regular blood donors from three provinces of Sistan-Balouchestan, Khuzestan and Gilan in Iran, from September 2018 to May 2019. A fully automated system, based on hemagglutination, was used to Rh typing of blood samples. RESULTS: The prevalence of Rh antigens were as follows: D: 88.9 %; E: 30.9 %; C: 74.1 %; e: 96.2 %; and c: 72.8 %. The most common antigen and phenotype were "e" and R1r (DCcee), respectively. CONCLUSION: Due to the high rate of alloimmunization incidence against Rh blood group antigens among multiple transfusion recipients, development of regular blood donor's Rh databank can facilitate extensive matching for the Rh antigens and it likely reduces the risk of alloimmunization.

Recombinant human lipocalin 2 acts as an antibacterial agent to prevent platelet contamination.

BACKGROUND: Bacterial contamination of platelet products is the major infectious risk in blood transfusion medicine, which can result in life-threatening sepsis in recipient. Lipocalin 2 (Lcn2) is an iron-sequestering protein in the antibacterial innate immune response, which inhibit bacterial growth. This study was aimed to evaluate the antibacterial property of Lcn2 in preventing bacterial contamination of platelets. METHODS: Recombinant Lcn2 was expressed in a eukaryotic expression system and following purification and characterization of the recombinant Lcn2, its minimum inhibitory concentration was determined. Then, platelet concentrates were inoculated with various concentrations of Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Enterococcus faecalis, and the antibacterial effects of Lcn2 was evaluated at 20-24 °C. RESULTS: Results revealed that Lcn2 effectively inhibited the growth of 1.5 × 10(4) CFU/ml S. epidermidis, P. aeruginosa, K. pneumoniae, E. coli, and E. faecalis at 40 ng/ml. At this concentration, Lcn2 also inhibited the growth of 1.5 × 10(3) CFU/ml Staphylococcus aureus and Proteus mirabilis. CONCLUSION: Recombinant Lcn2 inhibited growth of a variety of platelet-contaminating bacteria. Therefore, supplementation of platelet concentrates with Lcn2 may reduce bacterial contamination.