Frequency of CD36 deficiency in Thais analyzed by quantification of CD36 on cell surfaces and in plasma

Impacts of CD36 Variants on Plasma Lipid Levels and the Risk of Early-Onset Coronary Artery Disease: A Systematic Review and Meta-Analysis

Background: Recent studies have indicated that cluster of differentiation 36 (CD36) is closely linked to dyslipidemia and early-onset coronary artery disease (EOCAD). This study is aimed at investigating the impacts of CD36 gene variants on lipid profiles and EOCAD risk. Methods: PubMed, Cochrane Library, Central, CINAHL, and ClinicalTrials.gov were searched until June 15, 2024. Results: In total, 25 studies (11,494 individuals) were included for the analysis. The A allele carriers of the rs1761667 variant had higher high-density lipoprotein cholesterol (HDL-C) levels and higher EOCAD risk than noncarriers. In contrast, the G allele carriers of the rs1049673 and rs3211956 variants had lower low-density lipoprotein cholesterol (LDL-C) levels and lower EOCAD risk than noncarriers. Subgroup analysis indicated that the antiatherosclerotic impact and reduced EOCAD risk were primarily observed in Chinese with rs1049673 and rs3211956. Conclusions: The rs1761667, rs1049673, and rs3211956 variants of the CD36 gene have significant impacts on lipid levels and may serve as genetic markers for the risk of EOCAD primarily in Chinese. The impacts of CD36 variants on EOCAD risk are mediated, at least partly, by dyslipidemia. Genetic screening of CD36 gene variants may be helpful for early intervention or prevention of EOCAD in individuals with high risk factors.

Immunological platelet transfusion refractoriness: current insights from mechanisms to therapeutics

Although there have been tremendous improvements in the production and storage of platelets, platelet transfusion refractoriness (PTR) remains a serious clinical issue that may lead to various severe adverse events. The burden of supplying platelets is worsened by rising market demand and limited donor pools of compatible platelets. Antibodies against platelet antigens are known to activate platelets through FcγR-dependent or complement-activated channels, thereby rapidly eliminating foreign platelets. Recently, other mechanisms of platelet clearance have been reported. The current treatment strategy for PTR is to select appropriate and compatible platelets; however, this necessitates a sizable donor pool and technical assistance for costly testing. Consolidation of these mechanisms should be of critical significance in providing insight to establish novel therapeutics to target immunological platelet refractoriness. Therefore, the purposes of this review were to explore the modulation of the immune system over the activation and elimination of allogeneic platelets and to summarize the development of alternative approaches for treating and avoiding alloimmunization to human leukocyte antigen or human platelet antigen in PTR.

The polymorphism analysis for CD36 among platelet donors

CD36 may defect on platelets and/or monocytes in healthy individuals, which was defined as CD36 deficiency. However, we did not know the correlation between the molecular and protein levels completely. Here, we aim to determine the polymorphisms of the CD36 gene, RNA level, and CD36 on platelets and in plasma. The individuals were sequenced by Sanger sequencing. Bioinformational analysis was used by the HotMuSiC, CUPSAT, SAAFEC-SEQ, and FoldX. RNA analysis and CD36 protein detection were performed by qPCR, flow cytometry, and ELISA. In this study, we found c.1228_1239delATTGTGCCTATT (allele frequency = 0.0072) with the highest frequency among our cohort, and one mutation (c.1329_1354dupGATAGAAATGATCTTACTCAGTGTTG) was not present in the dbSNP database. 5 mutations located in the extracellular domain sequencing region with confirmation in deficient individuals, of which c.284T>C, c.512A>G, c.572C>T, and c.869T>C were found to have a deleterious impact on CD36 protein stability. Furthermore, the MFI of CD36 expression on platelets in the mutation-carry, deleterious-effect, and deficiency group was significantly lower than the no-mutation group (P < 0.0500). In addition, sCD36 levels in type II individuals were significantly lower compared with positive controls (P = 0.0060). Nevertheless, we found the presence of sCD36 in a type I individual. RNA analysis showed CD36 RNA levels in platelets of type II individuals were significantly lower than the positive individuals (P = 0.0065). However, no significant difference was observed in monocytes (P = 0.7500). We identified the most prevalent mutation (c.1228_1239delATTGTGCCTATT) among Kunming donors. Besides, our results suggested RNA level alterations could potentially underlie type II deficiency. Furthermore, sCD36 may hold promise for assessing immune reaction risk in CD36-deficient individuals, but more studies should be conducted to validate this hypothesis.

High-Throughput CD36 Phenotyping on Human Platelets Based on Sandwich ELISA and Mutant Gene Analysis

Background

CD36 deficiency is closely associated with fetal/neonatal alloimmune thrombocytopenia, platelet transfusion refractoriness, and other hemorrhage disorders, particularly in Asian and African populations. There is a clinical need for rapid and high-throughput methods of platelet CD36 (pCD36) phenotyping to improve the availability of CD36 typing of donors and assist clinical blood transfusions for patients with anti-CD36 antibodies. Such methods can also support the establishment of databases of pCD36-negative phenotypes.

Study Design and Methods

A sandwich enzyme-linked immunosorbent assay (ELISA) for CD36 phenotyping of human platelets was developed using anti-CD36 monoclonal antibodies. The reliability of the assay was evaluated by calculating the intra-assay and inter-assay coefficients of variation (CV). A total of 1,691 anticoagulant whole blood samples from healthy blood donors were randomly selected. PCD36 expression was measured using a sandwich ELISA. PCD36 deficiency was confirmed by flow cytometry (FC). Mutations underlying pCD36 deficiency were identified using polymerase chain reaction sequence-based typing (PCR-SBT).

Results

The sandwich ELISA for pCD36 phenotyping had high reliability (intra-assay CV, 2.1-4.8%; inter-assay CV, 2.3-5.2%). The sandwich ELISA was used to screen for CD36 expression on platelets isolated from 1,691 healthy blood donors. Of these, 36 samples were pCD36-negative. FC demonstrated absence of CD36 expression on monocytes in three of the 36 cases. In the present study population, the frequency of CD36 deficiency was 2.13% (36/1,691), of which 0.18% (3/1,691) was type I deficiency and 1.95% (33/1,691) was type II deficiency. In addition, we used PCR-SBT to characterize the gene mutations in exons 3-14 of the CD36 gene in 27 cases of CD36 deficiency and discovered 10 types of mutations in 13 pCD36-negative samples.

Conclusion

The present study describes the development and characterization of a highly reliable sandwich ELISA for high-throughput screening for pCD36 expression. This novel method is feasible for clinical applications and provides a useful tool for the establishment of databases of pCD36-negative phenotype donors.

Ligand-dependent CD36 functions in cancer progression, metastasis, immune response, and drug resistance

CD36, a multifunctional glycoprotein, has been shown to play critical roles in tumor initiation, progression, metastasis, immune response, and drug resistance. CD36 serves as a receptor for a wide range of ligands, including lipid-related ligands (e.g., long-chain fatty acid (LCFA), oxidized low-density lipoprotein (oxLDL), and oxidized phospholipids), as well as protein-related ligands (e.g., thrombospondins, amyloid proteins, collagens I and IV). CD36 is overexpressed in various cancers and may act as an independent prognostic marker. While it was initially identified as a mediator of anti-angiogenesis through its interaction with thrombospondin-1 (TSP1), recent research has highlighted its role in promoting tumor growth, metastasis, drug resistance, and immune suppression. The varied impact of CD36 on cancer is likely ligand-dependent. Therefore, we focus specifically on the ligand-dependent role of CD36 in cancer to provide a critical review of recent advances, perspectives, and challenges.

Frequency and molecular basis of CD36 deficiency among platelet donors in Kunming, China

CD36 is a multifunctional receptor expressed on the surface of many cell types. Among healthy individuals, CD36 may be absent on platelets and monocytes (type I deficiency) or platelets alone (type II deficiency). However, the exact molecular mechanisms underlying CD36 deficiency remain unclear. In this study, we aimed to identify individuals with CD36 deficiency and investigate the molecular basis underlying it. Blood samples were collected from platelet donors at Kunming Blood Center. Platelets and monocytes were isolated and CD36-expression levels were analyzed using flow cytometry. DNA from whole blood and mRNA isolated from monocytes and platelets of individuals with CD36 deficiency were analyzed using polymerase chain reaction (PCR) testing. The PCR products were cloned and sequenced. Among the 418 blood donors,7 (1.68%) were CD36 deficient: 1 (0.24%) with type I deficiency and 6(1.44%) with type II deficiency. Six heterozygous mutations occurred, including c.268C>T (in type I individuals), c.120 + 1 G>T, c.268C>T, c.329_330del/AC, c.1156 C>T, c.1163A>C, and c.1228_1239del/ATTGTGCCTATT (in type II individuals). Mutations were not detected in one type II individual . At the cDNA level, only mutant, but not wild-type, transcripts were detected in the platelets and monocytes of type I individual. In type II individuals, only mutant transcripts were found in platelets, whereas monocytes possessed wild-type and mutant transcripts. Interestingly, only alternative splicing transcripts were observed in the individual without mutation. We report the incidence rates of type I and II CD36 deficiencies among platelet donors in Kunming. Molecular genetic analyses of DNA and cDNA demonstrated that homozygous mutations on the cDNA level in platelets and monocytes or platelets alone identified type I and II deficiencies, respectively. Furthermore, alternatively spliced products also potentially contribute to the mechanism of CD36 deficiency.

Generation of induced pluripotent stem cell line derived from FNAIT patient with CD36 deficiency mutations

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) caused by anti-CD36 isoantibodies is a common disease and the frequency of type I CD36 deficiency is relatively high in eastern Asian populations.Currently, patient-specific induced pluripotent stem cells (hiPSC) are believed to be useful tools for studying anti-CD36 mediated FNAIT and finding new therapeutic approaches to the disease.We generated an iPSC line from peripheral blood mononuclear cells of a patient carrying a 329-330delAC of the CD36 gene.The iPSC expressed pluripotency markers, gave rise to derivatives of three germ layers during spontaneous differentiation, had a normal karyotype, and retained the patient-specific mutation.

Diagnostik und Therapie einer Anti-CD36-induzierten neonatalen Alloimmunthrombozytopenie

Mütterliche Antikörper gegen das HPA-1a auf kindlichen Thrombozyten sind der Hauptverursacher einer fetalen oder neonatalen Alloimmunthrombozytopenie (FNAIT). In asiatischen Populationen wurden wiederholt Isoantikörper gegen CD36 als ursächlich im Zusammenhang mit der FNAIT beschrieben, wohingegen in Mitteleuropa die CD36-Defizienz und damit die Möglichkeit einer Immunisierung praktisch unbekannt sind. Das erschwert deutlich die Transfusion mit kompatiblen Thrombozyten bei FNAIT-Fällen, z. B. bei Neugeborenen asiatischer Abstammung. Bei einem Neugeborenen arabischstämmiger Eltern wurde eine Anti-CD36-induzierte FNAIT diagnostiziert. Die Thrombozytenwerte konnten erfolgreich durch die Gabe HPA-unausgewählter Apheresethrombozytenkonzentrate (ATK) stabilisiert werden. Durch ein vorangegangenes Forschungsprojekt zum CD36-Screening bei Blutspendern arabischer Herkunft stand zusätzlich kurz darauf ein ATK mit sehr schwacher CD36-Expression zur Verfügung, das aber nicht mehr benötigt wurde. Dieser Fall weist somit alternative Therapiemöglichkeiten bei einer Anti-CD36-induzierten FNAIT auf.

Platelet CD36 deficiency is present in 2.6% of Arabian individuals and can cause NAIT and platelet refractoriness

BACKGROUND

CD36 isoantibodies are capable of inducing neonatal alloimmune thrombocytopenia (NAIT) and platelet refractoriness. As to now the CD36 type I deficiency has been reported in East Asian and African individuals. However, it is virtually unknown in Caucasians. The aim of this study was to display the prevalence of the CD36 deficiency within parts of the Arabian population in Germany. Secondly, we are presenting the case of a newborn suffering from NAIT which was induced by CD36 antibody.

METHODS

Platelet (p) CD36 was determined by flow cytometry on 1328 samples mainly from individuals of Arabian origin and a family with a neonate affected by NAIT. DNA sequencing was performed on all pCD36-negative samples.

RESULTS

Thirty-five (2.64%) of all donor samples were pCD36 negative, 19 (1.43%) had a weak expression. Including only individuals from the Arabian peninsula, frequencies were 3.39% and 1.75%, respectively. CD36 type I deficiency on both platelets and monocytes combined with a CD36 isoantibody were detected in the mother of the NAIT baby. The baby was successfully transfused with two HPA-unselected platelet concentrates. In case of need, two platelet units with a weak pCD36 expression were on hand. A total of 45 different CD36 mutations were detected within pCD36-negative individuals, some being homozygous, most of them only present on one allele.

CONCLUSION

The CD36-negative phenotype is present in a significant number of individuals of Arabian origin and enables CD36 isoimmunization in NAIT or refractoriness. Blood transfusion services should be aware of such cases.