In Vivo Detection of Retinal Ganglion Cell Stress in Rodents with DARC.

DARC (detection of apoptosing retinal cells) uses fluorescently tagged Annexin A5 to identify retinal apoptosis non-invasively in vivo using a confocal laser scanning ophthalmoscope (cSLO). This can provide insights into the presence and progression of disease pathology and the efficacy of neuroprotective intervention. The methods of administration, imaging, and quantification of DARC, including the operation of the cSLO, are described here.

Designing an effective malaria vaccine targeting Plasmodium vivax Duffy-binding protein.

Malaria caused by the Plasmodium vivax parasite is a major global health burden. Immunity against blood-stage infection reduces parasitemia and disease severity. Duffy-binding protein (DBP) is the primary parasite protein responsible for the invasion of red blood cells and it is a leading subunit vaccine candidate. An effective vaccine, however, is still lacking despite decades of interest in DBP as a vaccine candidate. This review discusses the reasons for targeting DBP, the challenges associated with developing a vaccine, and modern structural vaccinology methods that could be used to create an effective DBP vaccine. Next-generation DBP vaccines have the potential to elicit a broadly protective immune response and provide durable and potent protection from P. vivax malaria.

Prospects for targeting ACKR1 in cancer and other diseases.

The chemokine network is comprised of a family of signal proteins that encode messages for cells displaying chemokine G-protein coupled receptors (GPCRs). The diversity of effects on cellular functions, particularly directed migration of different cell types to sites of inflammation, is enabled by different combinations of chemokines activating signal transduction cascades on cells displaying a combination of receptors. These signals can contribute to autoimmune disease or be hijacked in cancer to stimulate cancer progression and metastatic migration. Thus far, three chemokine receptor-targeting drugs have been approved for clinical use: Maraviroc for HIV, Plerixafor for hematopoietic stem cell mobilization, and Mogalizumab for cutaneous T-cell lymphoma. Numerous compounds have been developed to inhibit specific chemokine GPCRs, but the complexity of the chemokine network has precluded more widespread clinical implementation, particularly as anti-neoplastic and anti-metastatic agents. Drugs that block a single signaling axis may be rendered ineffective or cause adverse reactions because each chemokine and receptor often have multiple context-specific functions. The chemokine network is tightly regulated at multiple levels, including by atypical chemokine receptors (ACKRs) that control chemokine gradients independently of G-proteins. ACKRs have numerous functions linked to chemokine immobilization, movement through and within cells, and recruitment of alternate effectors like ß-arrestins. Atypical chemokine receptor 1 (ACKR1), previously known as the Duffy antigen receptor for chemokines (DARC), is a key regulator that binds chemokines involved in inflammatory responses and cancer proliferation, angiogenesis, and metastasis. Understanding more about ACKR1 in different diseases and populations may contribute to the development of therapeutic strategies targeting the chemokine network.

Association between FY* 02N. 01 and the severity of COVID-19: initial observations

ABSTRACT Introduction The pro-inflammatory immune response underlies severe cases of COVID-19. Antigens of the Duffy blood group systems are receptors for pro-inflammation chemokines. The ACKR1 c.-67T>C gene variation silences the expression of Duffy antigens on erythrocytes and individuals presenting this variant in homozygosity have impaired inflammatory response control. Our aim was to evaluate the association between the ACKR1 c.-67T>C and the severity of COVID-19. Methods This was a retrospective single-center case-control study, enrolling 164 participants who were divided into four groups: 1) Death: COVID-19 patients who died during hospitalization; 2) Hospital Discharge: COVID-19 patients who were discharged for home after hospitalizations; 3) Convalescent Plasma Donors: COVID-19 patients who were not hospitalized, and; 4) Controls: patients with diagnosis other than COVID-19. Patients were genotyped for the ACKR1 c.-67T>C (FY*02 N.01 allele) and the frequency of individuals presenting the altered allele was compared between the groups. Results The groups significantly differed in terms of the percentage of patients presenting at least one FY*02N.01 allele: 36.8% (Death group), 37% (Hospital Discharge group), 16.1% (Convalescent Plasma group) and 16.2% (Control group) (p= 0.027). The self-declared race (p < 0.001) and the occurrence of in hospital death (p= 0.058) were independently associated with the presence of the FY*02N.01 allele. Hypertension (p < 0.001), age (p < 0.001) and the presence of at least one FY*02N.01 allele (p= 0.009) were independently associated with the need for hospitalization. Conclusion There is a suggestive association between the presence of the FY*02N.01 and the severity of COVID-19. This may be a mechanism underlying the worse prognosis for Afro-descendants infected with SARS-CoV-2.

Association between FY*02N.01 and the severity of COVID-19: initial observations.

Introduction: The pro-inflammatory immune response underlies severe cases of COVID-19. Antigens of the Duffy blood group systems are receptors for pro-inflammation chemokines. The ACKR1 c.-67T>C gene variation silences the expression of Duffy antigens on erythrocytes and individuals presenting this variant in homozygosity have impaired inflammatory response control. Our aim was to evaluate the association between the ACKR1 c.-67T>C and the severity of COVID-19. Methods: This was a retrospective single-center case-control study, enrolling 164 participants who were divided into four groups: 1) Death: COVID-19 patients who died during hospitalization; 2) Hospital Discharge: COVID-19 patients who were discharged for home after hospitalizations; 3) Convalescent Plasma Donors: COVID-19 patients who were not hospitalized, and; 4) Controls: patients with diagnosis other than COVID-19. Patients were genotyped for the ACKR1 c.-67T>C (FY*02 N.01 allele) and the frequency of individuals presenting the altered allele was compared between the groups. Results: The groups significantly differed in terms of the percentage of patients presenting at least one FY*02N.01 allele: 36.8% (Death group), 37% (Hospital Discharge group), 16.1% (Convalescent Plasma group) and 16.2% (Control group) (p = 0.027). The self-declared race (p < 0.001) and the occurrence of in hospital death (p = 0.058) were independently associated with the presence of the FY*02N.01 allele. Hypertension (p < 0.001), age (p < 0.001) and the presence of at least one FY*02N.01 allele (p = 0.009) were independently associated with the need for hospitalization. Conclusion: There is a suggestive association between the presence of the FY*02N.01 and the severity of COVID-19. This may be a mechanism underlying the worse prognosis for Afro-descendants infected with SARS-CoV-2.

Detecting retinal cell stress and apoptosis with DARC: Progression from lab to clinic.

DARC (Detection of Apoptosing Retinal Cells) is a retinal imaging technology that has been developed within the last 2 decades from basic laboratory science to Phase 2 clinical trials. It uses ANX776 (fluorescently labelled Annexin A5) to identify stressed and apoptotic cells in the living eye. During its development, DARC has undergone biochemistry optimisation, scale-up and GMP manufacture and extensive preclinical evaluation. Initially tested in preclinical glaucoma and optic neuropathy models, it has also been investigated in AMD, Alzheimer's, Parkinson's and Diabetic models, and used to assess efficacy of therapies. Progression to clinical trials has not been speedy. Intravenous ANX776 has to date been found to be safe and well-tolerated in 129 patients, including 16 from Phase 1 and 113 from Phase 2. Results on glaucoma and AMD patients have been recently published, and suggest DARC with an AI-aided algorithm can be used to predict disease activity. New analyses of DARC in GA (Geographic Atrophy) prediction are reported here. Although further studies are needed to validate these findings, it appears there is potential for the technology to be used as a biomarker. Much larger clinical studies will be needed before it can be considered as a diagnostic, although the relatively non-invasive nature of the nasal as opposed to intravenous administration would widen its acceptability in the future as a screening tool. This review describes DARC development and its progression into Phase 2 clinical trials from lab-based research. It discusses hypotheses, potential challenges, and regulatory hurdles in translating technology.

COVID-19: Mechanistic Model of the African Paradox Supports the Central Role of the NF-κB Pathway.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has expanded into a global pandemic, with more than 220 million affected persons and almost 4.6 million deaths by 8 September 2021. In particular, Europe and the Americas have been heavily affected by high infection and death rates. In contrast, much lower infection rates and mortality have been reported generally in Africa, particularly in the sub-Saharan region (with the exception of the Southern Africa region). There are different hypotheses for this African paradox, including less testing, the young age of the population, genetic disposition, and behavioral and epidemiological factors. In the present review, we address different immunological factors and their correlation with genetic factors, pre-existing immune status, and differences in cytokine induction patterns. We also focus on epidemiological factors, such as specific medication coverage, helminth distribution, and malaria endemics in the sub-Saharan region. An analysis combining different factors is presented that highlights the central role of the NF-κB signaling pathway in the African paradox. Importantly, insights into the interplay of different factors with the underlying immune pathological mechanisms for COVID-19 can provide a better understanding of the disease and the development of new targets for more efficient treatment strategies.

Sequence analysis of Plasmodium vivax Duffy binding proteins reveals the presence of unique haplotypes and diversifying selection in Ethiopian isolates.

BACKGROUND: Red blood cell invasion by the Plasmodium vivax merozoite requires interaction between the Duffy antigen receptor for chemokines (DARC) and the P. vivax Duffy-binding protein II (PvDBPII). Given that the disruption of this interaction prevents P. vivax blood-stage infection, a PvDBP-based vaccine development has been well recognized. However, the polymorphic nature of PvDBPII prevents a strain transcending immune response and complicates attempts to design a vaccine. METHODS: Twenty-three P. vivax clinical isolates collected from three areas of Ethiopia were sequenced at the pvdbpII locus. A total of 392 global pvdbpII sequences from seven P. vivax endemic countries were also retrieved from the NCBI archive for comparative analysis of genetic diversity, departure from neutrality, linkage disequilibrium, genetic differentiation, PvDBP polymorphisms, recombination and population structure of the parasite population. To establish a haplotype relationship a network was constructed using the median joining algorithm. RESULTS: A total of 110 variable sites were found, of which 44 were parsimony informative. For Ethiopian isolates there were 12 variable sites of which 10 were parsimony informative. These parsimony informative variants resulted in 10 nonsynonymous mutations. The overall haplotype diversity for global isolates was 0.9596; however, the haplotype diversity was 0.874 for Ethiopia. Fst values for genetic revealed Ethiopian isolates were closest to Indian isolates as well as to Sri Lankan and Sudanese isolates but further away from Mexican, Papua New Guinean and South Korean isolates. There was a total of 136 haplotypes from the 415 global isolates included for this study. Haplotype prevalence ranged from 36.76% to 0.7%, from this 74.2% were represented by single parasite isolates. None of the Ethiopian isolates grouped with the Sal I reference haplotype. From the total observed nonsynonymous mutations 13 mapped to experimentally verified epitope sequences. Including 10 non-synonymous mutations from Ethiopia. However, all the polymorphic regions in Ethiopian isolates were located away from DARC, responsible for junction formation. CONCLUSION: The results of this study are concurrent with the multivalent vaccine approach to design an effective treatment. However, the presence of novel haplotypes in Ethiopian isolates that were not shared by other global sequences warrant further investigation.

Hematologic safety of palbociclib in combination with endocrine therapy in patients with benign ethnic neutropenia and advanced breast cancer.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, including palbociclib, are approved to treat hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC) and are associated with hematologic toxicity. African American women, who are underrepresented in CDK4/6 inhibitor clinical trials, may experience worse neutropenia because of benign ethnic neutropenia. The authors specifically investigated the hematologic safety of palbociclib in African American women with HR-positive/HER2-negative ABC. METHODS: PALINA was a single-arm, open-label, investigator-initiated study of palbociclib (125 mg daily; 21 days on and 7 days off) plus endocrine therapy (ET) in African American women who had HR-positive/HER2-negative ABC and a baseline absolute neutrophil count ≥1000/mm3 (ClinicalTrials.gov identifier NCT02692755). The primary outcome was the proportion of patients who completed 12 months of therapy without experiencing febrile neutropenia or treatment discontinuation because of neutropenia. Single nucleotide polymorphism analysis was used to assess Duffy polymorphism status. RESULTS: Thirty-five patients received ≥1 dose of palbociclib plus ET; 19 had a Duffy null polymorphism (cytosine/cytosine). There were no reports of febrile neutropenia or permanent study discontinuation because of neutropenia. Significantly more patients with the Duffy null versus the wild-type variant had grade 3 and 4 neutropenia (72.2% vs 23.1%; P = .029) and required a palbociclib dose reduction (55.6% vs 7.7%; P = .008). Patients with the Duffy null versus the wild-type variant had lower overall relative dose intensity (mean ± SD, 81.89% ± 15.87 and 95.67% ± 5.89, respectively; P = .0026) and a lower clinical benefit rate (66.7% and 84.6%, respectively). CONCLUSIONS: These findings suggest that palbociclib is well tolerated in African American women with HR-positive/HER2-negative ABC. Duffy null status may affect the incidence of grade 3 neutropenia, dose intensity, and possibly clinical benefit.

The effect of erythrocyte transfusion on macrophage pyroptosis and inflammation in a sepsis model.

BACKGROUND: Sepsis is one of most common causes of death in the intensive care unit (ICU) due to infection and inflammation. The Duffy antigen receptor for chemokines (DARC) regulates pro-inflammatory cytokines, thus playing an important role in inflammation. OBJECTIVES: This study aimed to elucidate the correlation among erythrocyte transfusion, macrophage pyroptosis and inflammation in the progression of sepsis. MATERIAL AND METHODS: Alanine aminotransferase (ALT/GPT) activity was measured with the ALT/GPT activity measurement kit (Jiancheng Bio, Nanjing, China) according to the kit manual. The ET-1 concentration was measured with enzyme-linked immunosorbent assay (ELISA) using the endothelin-1 (ET-1) measurement kit (Jiancheng Bio) according to the kit manual. Apoptosis was evaluated using flow cytometry-based Annexin V staining assay. The cells were collected using centrifugation and resuspended in binding buffer. Ultrastructural analysis of pyroptotic body, the levels of interleukin (IL)-1ß, IL-18, IL-33, MIP-2, CXCL8, reactive oxygen species (ROS), and LTB4 were measured with ELISA. RESULTS: Our results showed that septic rats had impaired hepatic function and ET-1 levels. Erythrocyte transfusion upregulated DARC expression in the sepsis model. Erythrocyte transfusion also affected pyroptosis in macrophages, reduced the production of inflammatory cytokines, such as IL-1ß, IL-18 and IL-33, and alleviated cytotoxicity in the sepsis model. CONCLUSIONS: Erythrocyte transfusion may function as a therapeutic tool against sepsis by regulating pyroptosis, inflammation and cytotoxicity.

Plasmodium vivax Strains Use Alternative Pathways for Invasion.

Plasmodium vivax has 2 invasion ligand/host receptor pathways (P. vivax Duffy-binding protein/Duffy antigen receptor for chemokines [DARC] and P. vivax reticulocyte binding protein 2b/transferrin receptor [TfR1]) that are promising targets for therapeutic intervention. We optimized invasion assays with isogenic cultured reticulocytes. Using a receptor blockade approach with multiple P. vivax isolates, we found that all strains utilized both DARC and TfR1, but with significant variation in receptor usage. This suggests that P. vivax, like Plasmodium falciparum, uses alternative invasion pathways, with implications for pathogenesis and vaccine development.

Predicting wet age-related macular degeneration (AMD) using DARC (detecting apoptosing retinal cells) AI (artificial intelligence) technology.

OBJECTIVES: To assess a recently described CNN (convolutional neural network) DARC (Detection of Apoptosing Retinal Cells) algorithm in predicting new Subretinal Fluid (SRF) formation in Age-related-Macular-Degeneration (AMD). METHODS: Anonymized DARC, baseline and serial OCT images (n = 427) from 29 AMD eyes of Phase 2 clinical trial (ISRCTN10751859) were assessed with CNN algorithms, enabling the location of each DARC spot on corresponding OCT slices (n = 20,629). Assessment of DARC in a rabbit model of angiogenesis was performed in parallel. RESULTS: A CNN DARC count >5 at baseline was significantly (p = 0.0156) related to development of new SRF throughout 36 months. Prediction rate of eyes using unique DARC spots overlying new SRF had positive predictive values, sensitivities and specificities >70%, with DARC count significantly (p < 0.005) related to the magnitude of SRF accumulation at all time points. DARC identified earliest stages of angiogenesis in-vivo. CONCLUSIONS: DARC was able to predict new wet-AMD activity. Using only an OCT-CNN definition of new SRF, we demonstrate that DARC can identify early endothelial neovascular activity, as confirmed by rabbit studies. Although larger validation studies are required, this shows the potential of DARC as a biomarker of wet AMD, and potentially saving vision-loss.

Identification of a domain critical for Staphylococcus aureus LukED receptor targeting and lysis of erythrocytes.

Leukocidin ED (LukED) is a pore-forming toxin produced by Staphylococcus aureus, which lyses host cells and promotes virulence of the bacteria. LukED enables S. aureus to acquire iron by lysing erythrocytes, which depends on targeting the host receptor Duffy antigen receptor for chemokines (DARC). The toxin also targets DARC on the endothelium, contributing to the lethality observed during bloodstream infection in mice. LukED is comprised of two monomers: LukE and LukD. LukE binds to DARC and facilitates hemolysis, but the closely related Panton-Valentine leukocidin S (LukS-PV) does not bind to DARC and is not hemolytic. The interaction of LukE with DARC and the role this plays in hemolysis are incompletely characterized. To determine the domain(s) of LukE that are critical for DARC binding, we studied the hemolytic function of LukE-LukS-PV chimeras, in which areas of sequence divergence (divergence regions, or DRs) were swapped between the toxins. We found that two regions of LukE's rim domain contribute to hemolysis, namely residues 57-75 (DR1) and residues 182-196 (DR4). Interestingly, LukE DR1 is sufficient to render LukS-PV capable of DARC binding and hemolysis. Further, LukE, by binding DARC through DR1, promotes the recruitment of LukD to erythrocytes, likely by facilitating LukED oligomer formation. Finally, we show that LukE targets murine Darc through DR1 in vivo to cause host lethality. These findings expand our biochemical understanding of the LukE-DARC interaction and the role that this toxin-receptor pair plays in S. aureus pathophysiology.

Duffy blood group system and ocular toxoplasmosis.

Duffy blood group phenotypes [Fy(a + b-), Fy(a-b+), Fy(a + b+), Fy(a-b-)], characterized by the expression of Fya, and Fyb antigens, are present in red blood cells. Therefore, we hypothesize that the non-hematopoietic expression of these antigens might influence cell invasion by T. gondii. 576 consecutive patients from both genders were enrolled. The presumed OT clinical diagnosis was performed. Duffy phenotyping was performed by hemagglutination in gel columns and for the correct molecular characterization Fy(a-b-) phenotype, using PCR-RFLP. Anti-T. gondii IgG antibodies were detected by ELISA. Chi-square, Fisher's exact tests were used to compare the proportions. OT was present in 22.9% (n = 132) and absent in 77.1% (n = 444) of patients. The frequencies of anti-T. gondii IgG antibodies were higher in OT (127/132, 96.2%) than those without this disease (321/444, 72.3%) (p < .0001). None of the Duffy antigens or phenotypes were associated with T. gondii infection (χ2: 2.222, GL: 3, p = .5276) as well as the risk of OT (χ2: 0.771, GL: 3, p = .8566). Duffy blood group system phenotypes and their antigens do not constitute risk factors for infection by T. gondii infection and the development of OT.

Identification of ACKR1 variants associated with altered Duffy phenotype expression in blood donors from southern Brazil.

The atypical chemokine receptor 1 gene (ACKR1) is responsible for the clinically significant Duffy blood group. The main antigens of this system, Fya and Fyb, can be related to a null or weak expression of the DARC protein. In the present work, we aimed to identify ACKR1 gene variants in blood donors from southern Brazil based on discrepancies between their serological and molecular typing results. Then, we analyzed the association of these variants with the expression of the Duffy phenotype. The Fy antigen types were determined via hemagglutination and real-time PCR (c.125 G > A, c.265C > T and c.-67T > C SNPs) tests in a sample composed of 382 regular repetitive voluntary blood donors to the Blood Bank of Hospital de Clínicas de Porto Alegre. An inconclusive correlation between phenotype-genotype analyses was found in 11 (2.88 %) donors, and the entire ACKR1 gene was sequenced in these samples. Our investigation found 11 genetic variants, four of which (c.-541C > T, c.21 + 150C > T, c.22-58A > G, and c.298 G > A SNPs) seem to have putative functional effects on the structure and expression of DARC undertaken for in silico analysis (SIFT, PolyPhen-2 and RegulomeDB). Molecular events can result in apparent discrepancies between red cell genotypes and phenotypes. Our findings provided insight into the molecular background of FY antigens to improve technical approaches for red cell genotyping.

The diverse and complex roles of atypical chemokine receptors in cancer: From molecular biology to clinical relevance and therapy.

Chemokines regulate directed cell migration, proliferation and survival and are key components in cancer biology. They exert their functions by interacting with seven-transmembrane domain receptors that signal through G proteins (GPCRs). A subgroup of four chemokine receptors known as the atypical chemokine receptors (ACKRs) has emerged as essential regulators of the chemokine functions. ACKRs play diverse and complex roles in tumor biology from tumor initiation to metastasis, including cancer cell proliferation, adherence to endothelium, epithelial-mesenchymal transition (EMT), extravasation from blood vessels, tumor-associated angiogenesis or protection from immunological responses. This chapter gives an overview on the established and emerging roles that the atypical chemokine receptors ACKR1, ACKR2, ACKR3 and ACKR4 play in the different phases of cancer development and dissemination, their clinical relevance, as well as on the hurdles to overcome in ACKRs targeting as cancer therapy.

The emerging role of red blood cells in cytokine signalling and modulating immune cells.

For many years red blood cells have been described as inert bystanders rather than participants in intercellular signalling, immune function, and inflammatory processes. However, studies are now reporting that red blood cells from healthy individuals regulate immune cell activity and maturation, and red blood cells from disease cohorts are dysfunctional. These cells have now been shown to bind more than 50 cytokines and have been described as a sink for these molecules, and the loss of this activity has been correlated with disease progression. In this review, we summarise what is currently understood about the role of red blood cells in cytokine signalling and in modulating the activity of immune cells. We also discuss the implications of these findings for transfusion medicine and in furthering our understanding of anaemia of chronic inflammation. By bringing these disparate units of work together, we aim to shine a light on an area that requires significantly more investigation.

Interleukin-22 Induces the Infiltration of Visceral Fat Tissue by a Discrete Subset of Duffy Antigen Receptor for Chemokine-Positive M2-Like Macrophages in Response to a High Fat Diet.

Interleukin-22 (IL-22) is a cytokine with important functions in host defense and inflammatory responses and has recently been suggested to play a role in immune-inflammatory system in the context of obesity and its metabolic consequences. The specific cellular targets and mechanisms of IL-22-mediated obesity are largely unknown however. We here identified a previously unknown subset of monocyte-derived Duffy antigen receptors for chemokines (DARC)+ macrophages in epididymal fat adipose tissue and found that they are preferentially recruited into the crown-like structures of adipose tissue in the mouse upon high fat diet-induced obesity. Importantly, DARC+ macrophages highly express the IL-22 receptor (IL-22Ra1). Exposure to recombinant IL-22 shifts macrophages to an alternative M2 polarization pathway and augments DARC expression via a STAT5b signaling axis. STAT5b directly binds to the DARC promoter and a STAT5 inhibitor abrogates the IL-22-mediated induction of DARC. These M2-like DARC+ subpopulations of monocytes/macrophages were elevated in obese db/db mice compared to WT lean mice. Furthermore, subsets of CD14+ and/or CD16+ monocytes/macrophages within human peripheral blood mononuclear cell populations express DARC and the prevalence of these subsets is enhanced by IL-22 stimuli. This suggested that IL-22 is a critical cytokine that promotes the infiltration of adipose tissue macrophages, that regulate inflammatory processes. Taken together, our present findings provide important insights into the molecular mechanism by which IL-22 signal modulates DARC expression in M2-like macrophages.

Cytokine Levels in Inner Ear Fluid of Young and Aged Mice as Molecular Biomarkers of Noise-Induced Hearing Loss.

Sensorineural hearing loss (SNHL) is the most common sensory deficit worldwide, frequently caused by noise trauma and aging, with inflammation being implicated in both pathologies. Here, we provide the first direct measurements of proinflammatory cytokines in inner ear fluid, perilymph, of adolescent and 2-year-old mice. The perilymph of adolescent mice exposed to the noise intensity resulting in permanent auditory threshold elevations had significantly increased levels of IL-6, TNF-α, and CXCL1 6 h after exposure, with CXCL1 levels being most elevated (19.3 ± 6.2 fold). We next provide the first immunohistochemical localization of CXCL1 in specific cochlear supporting cells, and its presumed receptor, Duffy antigen receptor for chemokines (DARC), in hair cells and spiral ganglion neurons. Our results demonstrate the feasibility of molecular diagnostics of SNHL using only 0.5 µL of perilymph, and motivate future sub-µL based diagnostics of human SNHL based on liquid biopsy of the inner ear to guide therapy, promote hearing protection, and monitor response to treatment.

Duffy antigen receptor for chemokines gene polymorphisms and malaria in Mangaluru, India.

BACKGROUND: Duffy blood group antigens serve as receptors for Plasmodium vivax invasion into erythrocytes, and they are determined by polymorphisms of the Duffy antigen receptor for chemokines (DARC), also known as Fy glycoprotein (FY). Duffy negativity, i.e., absence of the antigens, protects against P. vivax infection and is rare among non-African populations. However, data on DARC polymorphisms and their impact on Plasmodium infection in India are scarce. METHODS: In a case-control study among 909 malaria patients and 909 healthy community controls in Mangaluru, southwestern India, DARC polymorphisms T-33C (rs2814778), G125A (rs12075), C265T (rs34599082), and G298A (rs13962) were genotyped. Associations of the polymorphisms with the odds of malaria, parasite species and manifestation were assessed. RESULTS: Among patients, vivax malaria (70%) predominated over falciparum malaria (9%) and mixed species infections (21%). DARC T-33C was absent and C265T was rare (1%). FYB carriage (deduced from DARC G125A) was not associated with the risk of malaria per se but it protected against severe falciparum malaria (P = 0.03), and hospitalization (P = 0.006) due to falciparum malaria. Vice versa, carriage of DARC 298A was associated with increased odds of malaria (aOR, 1.46 (1.07-1.99), P = 0.015) and vivax malaria (aOR, 1.60 (1.14-2.22), P = 0.006) and with several reported symptoms and findings of the patients. CONCLUSION: This report from southern India is the first to show an independent effect of the DARC 298A polymorphism on the risk of malaria. Functional studies are required to understand the underlying mechanism. Moreover, FYB carriage appears to protect against severe falciparum malaria in southern India.