Risk of new alloimmunization in patients on anti-CD38 treatment using tube LISS-IAT method.

BACKGROUND: Daratumumab is a monoclonal antibody that targets CD38, a transmembrane protein expressed on many cells including RBCs and to a greater extent on myeloma cells. It has been used for treatment of multiple myeloma and autoimmune diseases. Transfusion management of patients on such therapy can be challenging as these drugs cross-react with RBC surface antigens and cause panreactivity. MATERIAL AND METHODS: A retrospective study of the 68 patients treated with anti-CD38 from 2018-2023 was carried out. Data regarding transfusion history and antibody screens were analyzed. Depending whether they had immunohematological work-up before or during the treatment- DAT, antibody screen (CAT and tube), RBC pheno/genotyping and serologic cross-matches (CAT and tube) were performed for each patient. All cases with positive CAT IAT were retested in LISS-tube and cross-matches were performed with phenotypically matched units in LISS-tube. RESULTS: Antibody screen has shown panagglutination with all panel cells with low and variable agglutination intensity (weak to 2 +). Panagglutination remained positive for 1 - 6 months after drug cessation. Positive DAT was seen in 60,6% patients, while autocontrol was negative. Ficin treated panel-cells eliminated nonspecific reactivity. LISS-tube antibody screen and cross-matches were negative for all patients, apart from 3 patients who had preexisting antibodies. No new antibodies were detected during the course of the study. CONCLUSION: Among study group there were no newly identified alloantibodies, meaning that the policy of transfusing them with matched RBCs and performing IAT/cross-matches in tube is a safe and effective policy according to the findings of this study.

Platelet Serotonin (5-HT) Concentration, Platelet Monoamine Oxidase B (MAO-B) Activity and HTR2A, HTR2C, and MAOB Gene Polymorphisms in Asthma.

The complex role of the serotonin system in respiratory function and inflammatory diseases such as asthma is unclear. Our study investigated platelet serotonin (5-HT) levels and platelet monoamine oxidase B (MAO-B) activity, as well as associations with HTR2A (rs6314; rs6313), HTR2C (rs3813929; rs518147), and MAOB (rs1799836; rs6651806) gene polymorphisms in 120 healthy individuals and 120 asthma patients of different severity and phenotypes. Platelet 5-HT concentration was significantly lower, while platelet MAO-B activity was considerably higher in asthma patients; however, they did not differ between patients with different asthma severity or phenotypes. Only the healthy subjects, but not the asthma patients, carrying the MAOB rs1799836 TT genotype had significantly lower platelet MAO-B activity than the C allele carriers. No significant differences in the frequency of the genotypes, alleles, or haplotypes for any of the investigated HTR2A, HTR2C and MAOB gene polymorphisms have been observed between asthma patients and healthy subjects or between patients with various asthma phenotypes. However, the carriers of the HTR2C rs518147 CC genotype or C allele were significantly less frequent in severe asthma patients than in the G allele carriers. Further studies are necessary to elucidate the involvement of the serotonergic system in asthma pathophysiology.

RhD alloimmunization by DEL variant missed in donor testing.

INTRODUCTION: Exposure to normal or variably expressed RhD antigens in an antigen-negative individual can elicit an immune response and lead to the formation of clinically significant anti-D alloantibodies. We present the case of anti-D alloimmunization by DEL variant missed in routine blood donor screening. MATERIAL AND METHODS: Blood donors were typed for D antigen using the direct serologic micromethod. Nonreactive samples were confirmed in the indirect antiglobulin method with an IgM/IgG anti-D monoclonal reagent. Genomic DNA was extracted using a commercial QIAamp DNA Blood Mini kit on the QIAcube device (Qiaqen, Germany). RHD genotyping was performed using the PCR-SSP genotyping kits- Ready Gene D weak, Ready Gene D weak screen, Ready Gene CDE, and Ready Gene D AddOn (Inno-Train, Germany). Unidentified alleles were sent for DNA genome sequencing. RESULTS: After identifying DEL positive blood units in RhD negative blood donor pool, a look-back study was performed to determine if their previous donations caused alloimmunization in recipients. Out of 40 D negative recipients, one developed anti-D alloantibody after 45 days. The patient did not receive other RhD positive blood products. Blood donor typed D negative in direct and indirect agglutination method. RHD screening was positive, but RHD genotyping and DNA sequencing showed no mutation indicating the normal genotype. CONCLUSION: Currently used methods in RHD genotyping are insufficient to identify many variant alleles, especially intronic variations. We suggest additional gene investigation including yet unexplored regions of regulation and intron regions to justify our serological finding.

D variants in the population of D-negative blood donors in the north-eastern region of Croatia.

OBJECTIVES: The aim of this study was to determine RHESUS D GENE (RHD) allelic variants among Croatian D-negative blood donors and compare our results with respective data from other European countries. BACKGROUND: Altered or reduced D antigen expression can result in D variants, which can be mistyped and can lead to the alloimmunisation of the blood recipient. RHD genotyping can distinguish D variants: weak D, partial D and DEL, thus preventing alloimmunisation. MATERIAL/METHODS: A total of 6523 samples obtained from D-negative Croatian donors were screened for the presence of RHD using the real-time polymerase chain reaction (PCR) method. PCR-SSP was performed for D variant genotyping by using commercial genotyping kits (Inno-Train, Kronberg, Germany). Genomic DNA sequencing for all 10 exons of the RHD was performed when the genotyping kits failed to assign a D variant. RESULTS: RHD molecular screening revealed 23 (0.35%) RHD-PCR positive samples, all C/E positive, in decreasing frequency: 11 hybrid RHD-CE (2-9) D-CE variants, 4 weak partial D type 11 and 2 weak D type 2. Six samples remained unresolved and were sequenced. For 12 of 23 samples (excluding large hybrids), an adsorption/elution of anti-D serum was performed, confirming that all 12 were RhD+. The calculated frequency of clinically significant D alleles in RhD-negative blood donors was 1:543 (0.18%) or 1:53 (1.89%) in C/E blood donors. CONCLUSION: Data on the significant frequency of D variants among serologically D-negative blood donors in the north-eastern region of Croatia could help in introducing RHD molecular screening of blood donors in a routine workflow.

Plasma Brain-Derived Neurotrophic Factor (BDNF) Concentration and BDNF/TrkB Gene Polymorphisms in Croatian Adults with Asthma.

Brain-derived neurotrophic factor (BDNF) and its tropomyosin-related kinase B (TrkB) receptor might contribute to normal lung functioning and immune responses; however, their role in asthma remains unclear. Plasma BDNF concentrations, as well as BDNF and NTRK2 (TrkB gene) polymorphisms, were investigated in 120 asthma patients and 120 healthy individuals using enzyme-linked immunosorbent assay and polymerase chain reaction, respectively. The genotype and allele frequencies of BDNF Val66Met (rs6265) and NTRK2 rs1439050 polymorphisms did not differ between healthy individuals and asthma patients, nor between patients grouped according to severity or different asthma phenotypes. Although plasma BDNF concentrations were higher among healthy subjects carrying the BDNF Val66Met GG genotype compared to the A allele carriers, such differences were not detected in asthma patients, suggesting the influences of other factors. Plasma BDNF concentration was not affected by NTRK2 rs1439050 polymorphism. Asthma patients had higher plasma BDNF concentrations than control subjects; however, no differences were found between patients subdivided according to asthma severity, or Type-2, allergic, and eosinophilic asthma. Higher plasma BDNF levels were observed in asthma patients with aspirin sensitivity and aspirin-exacerbated respiratory disease. These results suggest that plasma BDNF may serve as a potential peripheral biomarker for asthma, particularly asthma with aspirin sensitivity.

ABO blood group genotypes and ventilatory dysfunction in patients with allergic and nonallergic asthma.

Aim ABO blood group genotypes are established as a genetic factor in pathophysiology of various diseases, such as cardiovascular disorders, cancers, infectious diseases and there is rising evidence of their involvement in other conditions. The aim of this study was to determine if ventilatory changes of lung function in asthma, measured by biomarkers/parameters, are connected to certain ABO blood group genotypes in Croatia. Methods A case-control study included 149 patients with asthma and 153 healthy individuals (blood donors). ABO genotyping on five main alleles was performed using PCR-SSP method. All patients had spirometry performed and severity of asthma was estimated. Clinical parameters of spirometry (FEV1, FEV/FVC, PEF), biomarkers FeNO, IgE and pO2 were measured. The χ2 test, Fisher's test, Kruskal-Wallis test and Spearman's correlation coefficients with p<0.05 were used as statistically significant. Results There was no determined statistically significant difference in both ABO genotypes and phenotypes between patient and control groups. Comparison of the lung function in different ABO phenotypes in asthmatic patients also did not show any statistically significant differences in FEV1 values, FEV/FVC ratio or PEF. Statistically significant differences in oxygenation between different ABO blood types have not been noticed (p=0.326). Differences in quantitative values of biomarkers (FeNO and IgE) between different ABO blood phenotypes in patients with asthma were not significant, except for IgE that had marginal values (p=0.074). Conclusion No correlation was found between certain ABO blood group genotypes and parameters/biomarkers of ventilatory dysfunction in patients with allergic and nonallergic asthma.

Health Sequelae of Tobacco Exposure in Childhood and Adolescence.

Tobacco consumption is one of the most common preventable cause of premature deaths worldwide. Persisting effects of exposure to tobacco smoke on children and adolescents are apparent during pregnancy and in early infancy, passive exposure to environmental tobacco smoke in home and elsewhere, and active smoking during adolescence. While, lung development in these stages of growth is not complete, tobacco smoke puts children and adolescents in danger of severe respiratory diseases and may interfere with the growth of their lungs. Active tobacco consumption by adolescents may have immediate adverse health outcomes such as addiction, impaired lung growth or reduced lung function. Much of the current evidence comes from longitudinal and cross-sectional longitudinal observational studies and propose that the strongest associations with smoke exposure are in the pregnancy and early childhood. The association of nicotine with respiratory system among children and adolescents is less clearly understood and the evidence primarily comes from in vitro and animal studies.

Three-Year Experience in NAT Screening of Blood Donors for Transfusion Transmitted Viruses in Croatia.

BACKGROUND: Croatia implemented individual donation (ID)-NAT testing of blood donors in 2013 for three viruses HBV, HCV, and HIV-1 as a mandatory test for all blood donors. This study assessed the impact of NAT screening 3 years after its implementation. METHODS: A total of 545,463 donations were collected and screened for HBV, HCV, and HIV-1 using the Procleix Ultrio Plus Assay. All initially reactive (IR) NAT samples were retested in triplicate and, if repeatedly reactive (RR), NAT discriminatory assay (dNAT) was performed. ID-NAT positive donations were confirmed by RT-PCR on the COBAS AmpliPrep/TaqMan platform. RESULTS: Out of 545,463 samples tested, 108 (0.02%) were RR in NAT. There were 82 (75,9%) HBV reactive, 16 (14.8%) HCV reactive, and 10 (9.3%) HIV-1 reactive samples. 51 (47.2%) samples were ID-NAT positive only. Out of these 51 NAT yield cases, 1 window period HIV-1 and 50 occult HBV infections (OBI) were determined. There were only two potential HBV DNA transmissions from OBI donors. CONCLUSION: The implementation of NAT screening for three viruses has improved blood safety in Croatia. During the 3-year period, 1 window period HIV-1 and a number of occult HBV donations were identified.