Genetics of transfusion recipient alloimmunization: can clues from susceptibility to autoimmunity pave the way?

Effects of diet on skin sensitization by nickel, poison ivy, and sesquiterpene lactones

Skin contact or exposure to sensitizers often occurs as a consequence of occupational exposures (e.g. poison ivy in forestry), wearing jewelry (e.g. nickel), or use of cosmetics (e.g. fragrances). However, many of the known skin sensitizers or their chemical variants are also consumed orally through foods or other sources. Since oral exposure to antigenic substances can lead to tolerance, consumption of sensitizers may impact the development and potency of skin sensitization, especially if the sensitizer is consumed early in life, prior to the first skin contact. To address this issue, we have reviewed human clinical and epidemiological literature relevant to this subject and evaluated whether early oral exposures to relevant sensitizers, or their chemical variants, are associated with reduced prevalence of skin sensitization to three main allergic sensitizers - nickel, urushiols of poison ivy, and sesquiterpene lactones of chrysanthemum and other plants.

Predictors of autoimmune hemolytic anemia in beta-thalassemia patients with underlying red blood cells autoantibodies

In beta-thalassemia patients, erythrocyte autoantibodies can remain silent or lead to Autoimmune Hemolytic Anemia (AIHA).The aim of this study was to identify predictors of AIHA in beta-thalassemia patients with positive Direct Antiglobulin Test (DAT), in Tunisia. This longitudinal prognosis study was carried out on beta-thalassemia patients with a positive confirmed DAT. Predictors of AIHA were identified the Kaplan-Meier method. A Cox model analysis was used to identify independent predictors. Among 385 beta thalassemia patients, 87 developed positive DAT (22.6%). Autoimmune hemolytic anemia was occurred in 25 patients. Multivariate analysis showed that AIHA was independently associated with beta-thalassemia intermedia and similar family history of AIHA. Splenectomy in patients with positive DAT was independently associated with an increased risk of AIHA (HR = 6.175, CI: 2.049-18.612, p < 0.001). The risk of developing AIHA was higher during the first 72 transfusions. Autoimmune hemolytic anemia was significantly associated with polyspecific DAT (anti-complement and anti-IgG), blood group AB and prior alloimmunization. Whereas transfusion by phenotypic and leukoreduced blood was a protective factor. In summary, splenectomy after autoimmunization, prior alloimmunization, DAT specificity (IgG with complement), thalassemia intermedia, AB blood group and family history of AIHA were strongly associated with AIHA. Leukoreduced blood transfusion had a proven preventive role.

Identification of genetic biomarkers for alloimmunization in sickle cell disease

Most sickle cell disease (SCD) patients rely on blood transfusion as their main treatment strategy. However, frequent blood transfusion poses the risk of alloimmunization. On average, 30% of SCD patients will alloimmunize while other patient groups form antibodies less frequently. Identification of genetic markers may help to predict which patients are at risk to form alloantibodies. The aim of this study was to evaluate whether genetic variations in the Toll-like receptor pathway or in genes previously associated with antibody-mediated conditions are associated with red blood cell (RBC) alloimmunization in a cohort of SCD patients. In this case-control study, cases had a documented history of alloimmunization while controls had received ≥20 RBC units without alloantibody formation. We used a customized single nucleotide polymorphism (SNP) panel to genotype 690 SNPs in 275 (130 controls, 145 cases) patients. Frequencies were compared using multiple logistic regression analysis. In our primary analysis, no SNPs were found to be significantly associated with alloimmunization after correction for multiple testing. However, in a secondary analysis with a less stringent threshold for significance we found 19 moderately associated SNPs. Among others, SNPs in TLR1/TANK and MALT1 were associated with a higher alloimmunization risk, while SNPs in STAM/IFNAR1 and STAT4 conferred a lower alloimmunization risk.

Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate

Background

Unexpected red blood cell alloantibodies can cause hemolytic transfusion reactions. In this study, the prevalence of alloimmunization, the rate of identification of alloantibodies and the rate of blood transfusion reactions among transfused patients were identified in a clinical emergency hospital in Brazil.

Methods

Transfusions and clinical records of patients who had a positive indirect antiglobulin test between January and December 2013 were analyzed.

Results

Of 1169 patients who received blood transfusions, 28 had positive indirect antiglobulin tests, with one patient having two positive tests at different times, resulting in 29 positive tests during the period of this study. Alloantibodies were identified in 58.6% (17/29) of the cases. In 27.5% (8/29), identification was inconclusive and it was not possible to confirm alloimmunization. The rate of red blood cell alloimmunization was 1.71% (21/1169). Of 21 cases of alloimmunization, four (19%) were unidentified due to an unusual agglutination profile. All identified alloantibodies were clinically significant (10/17 anti-Rh, 5/17 anti-Kell and 2/17 anti-MNS). In two patients who had positive indirect antiglobulin tests, one had an unidentified alloantibody, and the other had an inconclusive test and developed a hemolytic transfusion reaction.

Conclusion

The prevalence of clinically important red blood cell alloantibodies and hemolytic transfusion reactions among patients with unidentified alloantibodies suggests that specific laboratory techniques should be performed to identify alloantibodies in cases of pan-reactivity or autoantibodies to improve transfusion safety.

Organ damage mitigation with the Baskent Sickle Cell Medical Care Development Program (BASCARE)

The Eastern Mediterranean is among the regions where sickle cell disease (SCD) is common. The morbidity and mortality of this disease can be postponed to adulthood through therapies implemented in childhood. The present study focuses on the organ damage-reducing effects of the Baskent Sickle Cell Medical Care Development Program (BASCARE), which was developed by a team who lives in this region and has approximately 25 years of experience. The deliverables of the program included the development of an electronic health recording system (PRANA) and electronic vaccination system; the use of low citrate infusion in routine prophylactic automatic erythrocyte exchange (ARCE) programs including pregnant women; the use of leukocyte-filtered and irradiated blood for transfusion; the use of magnetic resonance imaging methods (T2) for the management of transfusion-related hemosiderosis; and the implementation of an allogeneic hematopoietic stem cell transplantation protocol for adult patients. The sample was composed of 376 study subjects and 249 control subjects. The hospital's Data Management System and the central population operating system were used for data collection. BASCARE enabled better analysis and interpretation of complication and mortality data. Vaccination rates against influenza and pneumococcal disease improved (21.5% vs 50.8% and 21.5% vs 49.2%, respectively). Effective and safe ARCE with low citrate infusion were maintained in 352 subjects (1003 procedures). Maternal and fetal mortality was prevented in 35 consecutive pregnant patients with ARCE. Chelating therapy rates reduced from 6.7% to 5%. Successful outcomes could be obtained in all 13 adult patients who underwent allogeneic peripheral stem cell transplantation from a fully matched, related donor. No patients died by day 100 or after the first year. Cure could be achieved without graft loss, grades III to IV acute graft versus host disease, extensive chronic graft versus host disease, or other major complications. The BASCARE program significantly improved patient care and thereby prolonged the life span of SCD patients (42 ± 13 years vs 29 ± 7 years, P < .001). We may recommend using such individualized programs in centers that provide health care for patients with SCD, in accordance with holistic approach due to the benign nature but malignant course of the disease.

Fatal delayed haemolytic transfusion reaction in a patient without previous transfusions but with an obstetric history of 13 pregnancies

Delayed haemolytic transfusion reaction is a rare, life-threatening complication of blood transfusion that has been typically described among patients with sickle cell disease (SCD) due to alloimmunisation induced by their exposure to red blood cell antigens through recurrent transfusions. We report the case of a patient who suffered from fatal delayed haemolytic transfusion reaction (DHTR) occurring 1 week after blood transfusion. Indirect antiglobulin testing confirmed the presence of anti-Kell antibodies that were absent in the pretransfusion sample. The patient did not receive blood transfusions in the past, but her obstetric history was remarkable for 13 pregnancies. Although DHTR occurs more commonly among patients with SCD, this type of reaction can occur in any patient who is able to mount an immune response. We would to like to draw the attention of physicians to this rare and potentially lethal complication of blood transfusion, especially in grand multiparous women.

Two Genetic Variations in the IRF8 region are associated with Behçet's disease in Han Chinese

Several modulatory factors in the TLR signaling pathway including IRF3, IRF7, IRF8, TRIM20, MYD88 and NF-κB1 have been associated with autoimmune disease. In this study, we investigated the association of 13 SNPs for these genes with Behçet’s disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. Haplotype and linkage disequilibrium (LD) analysis were performed by Haploview4.2. IRF8 mRNA expression and cytokine production was tested by real-time PCR and ELISA. Two SNPs near IRF8 were associated with BD (for rs17445836 GG genotype, Pc = 9.56 × 10⁻⁸, OR = 2.044; for rs11642873 AA genotype, Pc = 9.24 × 10⁻⁷, OR = 1.776). No significant association was found for the 13 SNPs tested with VKH syndrome. Haplotype analysis of the two positive SNPs revealed that the AG haplotype was significantly increased in BD patients (Pc = 2.60 × 10⁻⁸, OR = 1.646). Functional studies revealed an increased mRNA expression of IRF8 and IFN-γ production and a decreased production of IL-10 in rs17445836 carriers with the GG genotype. Increased expression of IRF8 as well as IFN-γ production and a decreased production of IL-10 were found in individuals carrying the rs11642873/AA genotype. In conclusion, this study indicates that IRF8 may contribute to the genetic susceptibility of BD by regulating IRF8 expression and cytokine production.

Are Immune Modulating Single Nucleotide Polymorphisms Associated with Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency. The purpose of this study is to determine if functional single nucleotide polymorphisms (SNPs) in immune-modulating genes pre-dispose infants to NEC. After Institutional Review Board approval and parental consent, buccal swabs were collected for DNA extraction. TaqMan allelic discrimination assays and BglII endonuclease digestion were used to genotype specific inflammatory cytokines and TRIM21. Statistical analysis was completed using logistic regression. 184 neonates were analyzed in the study. Caucasian neonates with IL-6 (rs1800795) were over 6 times more likely to have NEC (p = 0.013; OR = 6.61, 95% CI 1.48–29.39), and over 7 times more likely to have Stage III disease (p = 0.011; OR = 7.13, (95% CI 1.56–32.52). Neonates with TGFβ-1 (rs2241712) had a decreased incidence of NEC-related perforation (p = 0.044; OR = 0.28, 95% CI: 0.08–0.97) and an increased incidence of mortality (p = 0.049; OR = 2.99, 95% CI: 1.01 – 8.86). TRIM21 (rs660) was associated with NEC-related intestinal perforation (p = 0.038; OR = 4.65, 95% CI 1.09–19.78). In premature Caucasian neonates, the functional SNP IL-6 (rs1800795) is associated with both the development and increased severity of NEC. TRIM21 (rs660) and TGFβ-1 (rs2241712) were associated with NEC- related perforation in all neonates in the cohort. These findings suggest a possible genetic role in the development of NEC.