Detection of alloimmunization in Glanzmann Thrombasthenia and Bernard-Soulier Syndrome: Data from a Brazilian Center

ABSTRACT Introduction: The Glanzmann Thrombasthenia (GT) and Bernard-Soulier Syndrome (BSS) are rare hereditary disorders of platelet function. Their treatment often requires platelet transfusion, which can lead to the development of alloantibodies. Objective: In this study, we aim to develop a strategy for alloantibody detection and to describe the frequency of alloimmunization in a patient population from a single center in southeastern Brazil. Methods: Samples from patients with GT or BSS were tested using the Platelet Immunofluorescence Test (PIFT). If a positive result was obtained, a confirmatory step using the Monoclonal Antibody Immobilization of Platelet Antigens (MAIPA) and Luminex bead-based platelet assay (PAKLx) was executed. Main results: Among 11 patients with GT, we detected the presence of alloantibodies in 5 using PIFT, with confirmation through MAIPA and PAKLx in 2 (1 anti-HLA and 1 anti-HPA), resulting in a frequency of 18.1%. Among 4 patients with BSS, PIFT was positive in 3, with confirmation by MAIPA and PAKLx in 1 (anti-HLA), showing a frequency of 25%. The two patients with anti-HLA antibodies exhibited a panel reactive antibody (PRA-HLA) testing greater than 97%. Conclusion: Our study highlights the importance of identifying platelet alloimmunization in this patient population. The proposed algorithm for platelet alloantibodies detection allows resource optimization.

Association between antibiotic prophylaxis and adverse perinatal outcomes in premature rupture of membranes.

OBJECTIVE: The aim of this study was to evaluate the association between antibiotic prophylaxis and adverse perinatal outcomes in premature rupture of membranes. METHODS: This retrospective cohort included pregnant women with premature rupture of membranes (between 24 and 33+6 weeks) who used or did not use prophylactic antibiotics. Pearson's chi-square (χ²) test, Student's t-test, and binary logistic regression were used for statistical analysis. RESULTS: A significant effect was observed in patients with premature rupture of membranes using prophylactic antibiotics regarding amniotic fluid index (p=0.007), deepest vertical pocket (p=0.049), duration of antibiotic therapy (p≤0.001), C-reactive protein level upon admission (p≤0.001), leukocyte count upon admission (p=0.007), and length of stay in neonatal intensive care (p=0.047). A significant association was observed between the abovementioned patients and surfactant use during the neonatal period (p=0.04). A higher prevalence of surfactant use was noted in these patients (20.0 vs. 8.7%; p=0.04). CONCLUSION: No association was found between antibiotic prophylaxis and the presence of adverse perinatal outcomes in pregnant women with premature rupture of membranes between 24 and 33+6 weeks of gestation.

Association between antibiotic prophylaxis and adverse perinatal outcomes in premature rupture of membranes

SUMMARY OBJECTIVE: The aim of this study was to evaluate the association between antibiotic prophylaxis and adverse perinatal outcomes in premature rupture of membranes. METHODS: This retrospective cohort included pregnant women with premature rupture of membranes (between 24 and 33+6 weeks) who used or did not use prophylactic antibiotics. Pearson's chi-square (χ²) test, Student's t-test, and binary logistic regression were used for statistical analysis. RESULTS: A significant effect was observed in patients with premature rupture of membranes using prophylactic antibiotics regarding amniotic fluid index (p=0.007), deepest vertical pocket (p=0.049), duration of antibiotic therapy (p≤0.001), C-reactive protein level upon admission (p≤0.001), leukocyte count upon admission (p=0.007), and length of stay in neonatal intensive care (p=0.047). A significant association was observed between the abovementioned patients and surfactant use during the neonatal period (p=0.04). A higher prevalence of surfactant use was noted in these patients (20.0 vs. 8.7%; p=0.04). CONCLUSION: No association was found between antibiotic prophylaxis and the presence of adverse perinatal outcomes in pregnant women with premature rupture of membranes between 24 and 33+6 weeks of gestation.

Detection of alloimmunization in Glanzmann Thrombasthenia and Bernard-Soulier Syndrome: Data from a Brazilian Center.

INTRODUCTION: The Glanzmann Thrombasthenia (GT) and Bernard-Soulier Syndrome (BSS) are rare hereditary disorders of platelet function. Their treatment often requires platelet transfusion, which can lead to the development of alloantibodies. OBJECTIVE: In this study, we aim to develop a strategy for alloantibody detection and to describe the frequency of alloimmunization in a patient population from a single center in southeastern Brazil. METHODS: Samples from patients with GT or BSS were tested using the Platelet Immunofluorescence Test (PIFT). If a positive result was obtained, a confirmatory step using the Monoclonal Antibody Immobilization of Platelet Antigens (MAIPA) and Luminex bead-based platelet assay (PAKLx) was executed. MAIN RESULTS: Among 11 patients with GT, we detected the presence of alloantibodies in 5 using PIFT, with confirmation through MAIPA and PAKLx in 2 (1 anti-HLA and 1 anti-HPA), resulting in a frequency of 18.1%. Among 4 patients with BSS, PIFT was positive in 3, with confirmation by MAIPA and PAKLx in 1 (anti-HLA), showing a frequency of 25%. The two patients with anti-HLA antibodies exhibited a panel reactive antibody (PRA-HLA) testing greater than 97%. CONCLUSION: Our study highlights the importance of identifying platelet alloimmunization in this patient population. The proposed algorithm for platelet alloantibodies detection allows resource optimization.

Impact of HLA-G +3142C>G on the development of antibodies to blood group systems other than the Rh and Kell among sensitized patients with sickle cell disease.

BACKGROUND: Patients' inflammatory history is an important factor underlying red blood cell (RBC) alloimmunization, which is a frequent transfusion complication among individuals with sickle cell disease (SCD). HLA-G has been associated with different inflammatory and auto - immune diseases. Our goal was to verify whether the HLA-G + 3142 C>G and 14-bp Ins/Del variations are associated with RBC antibody development among SCD patients. METHODS: This was a single-center case-control study. SCD patients were randomly selected for the study and divided into two groups: 'Alloimmunized' and 'Nonalloimmunized' depending on the presence of irregular antibodies. The 'Alloimmunized'group was further divided into two subgroups according to the presence of only antibodies against the Rh and Kell blood group systems or the existence of antibodies to antigens of the other blood group systems. RESULTS: A total of 213 patients were included in the study (110 alloimmunized and 103 non-alloimmunized). The 'Alloimmunized' and 'Non-alloimmunized' groups did not differ statistically regarding the HLA-G + 14 bp Ins/Del ( p = 0.494) and + 3142 C>G ( p = 0.334). Individuals who had only antibodies against the Rh and Kell antigens had a frequency of HLA-G + 3142GG genotype almost twice as high compared to the groupwith antibodies against less immunogenic antigens ( p = 0.043). CONCLUSIONS: The genotype frequency of HLA-G + 3142 C>G differs among alloimmunized SCD patients, depending on the presence of antibodies against low immunogenic RBC antigens. This highlights a possible role played by the HLA-G molecule in the RBC alloimmunization process.