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Mucinous adenocarcinomas of the upper urinary tract are extremely rare, and the majority of information available comes from case reports or short case series. Intestinal metaplasia is considered a premalignant condition in carcinogenesis. Here we present a case of a 55-year-old male who presented with a left flank mass extending to the left hemiabdomen and macroscopic hematuria. Pathologic findings revealed that the kidney was transformed into a multiloculated cystic mass measuring 18 × 12 × 11 cm, with a dilated pelvicalyceal system obstructed by a stone at the renal hilus and filled with a gray, soft, gelatinous material. Histopathologic sections showed glandular metaplasia of the proximal ureter ascending to the renal pelvis, lined by intestinal-type columnar epithelium containing goblet cells admixed with malignant glands floating in abundant extracellular mucin, along with poorly differentiated areas composed of signet ring cells. Immunohistochemistry studies showed positive periodic acid Schiff (PAS)/periodic acid Schiff-diastase (PAS-D), consistent with the mucinous nature of the intracellular and extracellular materials. Positive immunohistochemical staining for CK7, CK20, and CDX2 (CK7+/CK20+/CDX2+) highlighted the intestinal differentiation of this neoplasm. This offers evidence for the intestinal metaplasia-dysplasia-carcinoma sequence rather than a teratomatous or coelomic epithelial origin in mucinous ovarian-like cystadenocarcinoma involving the renal pelvis.
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Corticosteroids have been utilized in modern medicine for decades. Many indications have been investigated across various treatment settings with both benefit and harm observed. Given the instability of critically ill patients, the increased risk of corticosteroid-related complications, and the pervasive comorbidities, patients who receive corticosteroids must be carefully managed. Common critical care disease states in which corticosteroids have been studied and are routinely utilized include acute respiratory distress syndrome, adrenal insufficiency, angioedema, asthma, chronic obstructive pulmonary disease, community-acquired pneumonia, coronavirus disease 2019, septic shock, and spinal cord injury. Benefits of corticosteroids include an improvement in disease state-specific outcomes, decreased hospital length of stay, decreased mechanical ventilatory support, and decreased mortality. The harm of corticosteroids is well documented through adverse effects that include, but are not limited to, hyperglycemia, tachycardia, hypertension, agitation, delirium, anxiety, immunosuppression, gastrointestinal bleeding, fluid retention, and muscle weakness. Furthermore, corticosteroids are associated with increased health care costs through adverse effects as well as drug acquisition and administration costs. Given the assortment of agents, dosing, benefits, risks, and utilization in the critical care setting, there may be difficulty with identifying the appropriate places for use of corticosteroids in therapy. There currently exists no comprehensive report detailing the use of corticosteroids in the aforementioned disease states within the critical care setting. This narrative review sets out to describe these in detail.
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Corticosteroides , Estado Terminal , Humanos , Corticosteroides/uso terapêutico , Corticosteroides/efeitos adversos , Corticosteroides/administração & dosagem , Cuidados Críticos/métodos , COVID-19RESUMO
Malaria sterile immunity has been reproducibly induced by immunization with Plasmodium radiation-attenuated sporozoites (RAS). Analyses of sera from RAS-immunized individuals allowed the identification of P. falciparum antigens, such as the circumsporozoite protein (CSP), the basis for the RTS, S and R21Matrix-M vaccines. Similar advances in P. vivax (Pv) vaccination have been elusive. We previously reported 42% (5/12) of sterile protection in malaria-unexposed, Duffy-positive (Fy +) volunteers immunized with PvRAS followed by a controlled human malaria infection (CHMI). Using a custom protein microarray displaying 515 Pv antigens, we found a significantly higher reactivity to PvCSP and one hypothetical protein (PVX_089630) in volunteers protected against P. vivax infection. In mock-vaccinated Fy + volunteers, a strong antibody response to CHMI was also observed. Although the Fy- volunteers immunized with non-irradiated Pv-infected mosquitoes (live sporozoites) did not develop malaria after CHMI, they recognized a high number of antigens, indicating the temporary presence of asexual parasites in peripheral blood. Together, our findings contribute to the understanding of the antibody response to P. vivax infection and allow the identification of novel parasite antigens as vaccine candidates.Trial registration: ClinicalTrials.gov number: NCT01082341.
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Vacinas Antimaláricas , Malária Falciparum , Malária Vivax , Malária , Animais , Humanos , Plasmodium vivax , Esporozoítos , Formação de Anticorpos , Imunização , Vacinação , Malária/prevenção & controle , Malária Falciparum/parasitologia , Malária Vivax/parasitologia , Plasmodium falciparumRESUMO
Members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family are important targets for protective immunity. Abnormal display of PfEMP1 on the surfaces of infected erythrocytes (IEs) and reduced cytoadhesion have been demonstrated in hemoglobin (Hb) AS and HbAC, inherited blood disorders associated with protection against severe P. falciparum malaria. We found that Ghanaian children with HbAS had lower levels of immunoglobulin G against several PfEMP1 variants and that this reactivity increased more slowly with age than in their HbAA counterparts. Moreover, children with HbAS have lower total parasite biomass than those with HbAA at comparable peripheral parasitemias, suggesting impaired cytoadhesion of HbAS IEs in vivo and likely explaining the slower acquisition of PfEMP1-specific immunoglobulin G in this group. In contrast, the function of acquired antibodies was comparable among Hb groups and appears to be intact and sufficient to control parasitemia via opsonization and phagocytosis of IEs.
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Hemoglobina Falciforme , Malária Falciparum , Criança , Humanos , Hemoglobina Falciforme/metabolismo , Plasmodium falciparum , Malária Falciparum/parasitologia , Gana , Proteínas de Protozoários , Eritrócitos/parasitologia , Imunoglobulina G , Anticorpos Antiprotozoários , Proteínas de Membrana/metabolismoRESUMO
Background: The surge in malaria cases and deaths in recent years, particularly in Africa, despite the widespread implementation of malaria-control measures could be due to inefficiencies in malaria control and prevention measures in malaria-endemic communities. In this context, this study provides the malaria situation report among children in three Municipalities in Northern Ghana, where Seasonal Malaria Chemotherapy (SMC) is implemented by Ghana Health Service (GHS). Methods: A cross-sectional household survey was carried out to assess the malaria knowledge, attitudes, and practices (KAP) and malaria prevalence in 394 households in 13 rural communities in the Kumbugu, Nanton and Tolon Municipalities, Northern Region, Ghana. This was followed by screening for P. falciparum infection with anti-HRP2 RDT and PCR among children 1-17 years in the households. Plasma levels of IgG specific for crude P. falciparum antigen (3D7) and four recombinant malaria antigens (CSP, GLURP, MSP3, and Pfs230) were assessed by ELISA. The malaria and parasitaemia data were converted into frequency and subgroup proportions and disaggregated by study sites and demographic information of the participants. The ELISA data was converted to arbitrary units (AU) and similarly compared across study sites and demographic information. Results: The P. falciparum infection rate and frequency of malaria were high in the study areas with significant age-dependent and inter-community differences, which were reflected by differences in plasma levels of P. falciparum-specific IgG. Over 60% of households reported the use of bed nets and indoor insecticide sprays/coils, and 14% mentioned bush clearing around homes (14%) as malaria preventive measures. Community health centres were the preferred place for households (88%) to seek malaria treatment but over-the-counter drug stores were the major source (66%) of their antimalarials. Overall, malaria preventive and treatment practices were sub-optimal. Conclusions: P. falciparum infection and malaria are still high in the studied communities, indicating that preventive and control measures against the disease in the region remain inadequate. Efforts to ensure high SMC compliance and to improve preventative and treatment practices thus seem cost-beneficial "low-hanging fruits" in the fight against malaria in the Northern Region of Ghana.
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STUDY OBJECTIVE: Significant practice variation exists when selecting between hydrocortisone and vasopressin as second line agents in patients with septic shock in need of escalating doses of norepinephrine. The goal of this study was to assess differences in clinical outcomes between these two agents. DESIGN: Multicenter, retrospective, observational study. SETTING: Ten Ascension Health hospitals. PATIENTS: Adult patients with presumed septic shock receiving norepinephrine prior to study drug initiation between December 2015 and August 2021. INTERVENTION: Vasopressin (0.03-0.04 units/min) or hydrocortisone (200-300 mg/day). MEASUREMENTS AND MAIN RESULTS: A total of 768 patients were included with a median (interquartile range) SOFA score of 10 (8-13), norepinephrine dose of 0.3 mcg/kg/min (0.1-0.5 mcg/kg/min), and lactate of 3.8 mmol/L (2.4-7.0 mmol/L) at initiation of the study drug. A significant difference in 28-day mortality was noted favoring hydrocortisone as an adjunct to norepinephrine after controlling for potential confounding factors (OR 0.46 [95% CI, 0.32-0.66]); similar results were seen following propensity score matching. Compared to vasopressin, hydrocortisone initiation was also associated with a higher rate of hemodynamic responsiveness (91.9% vs. 68.2%, p < 0.01), improved resolution of shock (68.8% vs. 31.5%, p < 0.01), and reduced recurrence of shock within 72 h (8.7% vs. 20.7%, p < 0.01). CONCLUSIONS: Addition of hydrocortisone to norepinephrine was associated with a lower 28-day mortality in patients with septic shock, compared to the addition of vasopressin.
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Norepinefrina , Choque Séptico , Humanos , Adulto , Norepinefrina/uso terapêutico , Hidrocortisona/uso terapêutico , Vasoconstritores/uso terapêutico , Estudos Retrospectivos , Choque Séptico/tratamento farmacológico , Vasopressinas/uso terapêuticoRESUMO
BACKGROUND: Malaria remains a leading public health problem worldwide. Co-infections with other pathogens complicate its diagnosis and may modify the disease's clinical course and management. Similarities in malaria clinical presentation with other infections and overlapping endemicity result in underdiagnosis of co-infections and increased mortality. Thus, the aim of this study was to determine the seroprevalence of viral and bacterial pathogens among diagnosed malaria patients in malaria-endemic areas in Venezuela. METHODS: A cross-sectional study was conducted on malaria patients attending three reference medical centres in Ciudad Bolivar, Venezuela. Clinical evaluation and laboratory tests for dengue virus (DENV), chikungunya virus (CHIKV), viral hepatitis [hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV)], and leptospirosis (LEP) were performed by enzyme-linked immunosorbent assays. Previous exposure to these pathogens was defined by the presence of specific immunoglobulin (Ig) G, and co-infection or recent exposure (CoRE) was determined by the presence of specific IgM alone or IgM + IgG. Data analysis considered descriptive statistics. Parameter distribution was statistically evaluated using Kolmogorov-Smirnov test and the necessary comparison tests. Odds ratio (OR) for complications was determined according to CoRE presence with a 95% confidence interval (CI). RESULTS: A total of 161 malaria patients were studied, 66% infected with Plasmodium vivax, 27% with P. falciparum, and 7.5% harboured P. vivax/P. falciparum mixed infection. Previous exposure to DENV (60%) and CHIKV (25%) was frequent. CoRE was confirmed in 55 of the 161 malaria patients (34%) and were more frequent in P. falciparum (49%) than in P. vivax (29%) and mixed malaria patients (25%) (OR = 2.43, 95% CI: 1.39-4.25, P = 0.018). The most frequent CoRE was DENV (15%), followed by HAV (12%), HBV (6.2%), CHIKV (5.5%), and LEP (3.7%); HCV CoRE was absent. Complicated malaria was significantly more frequent in patients with CoRE (56%) than those without CoRE (36%; OR = 2.31, 95% CI: 1.18-4.92, P = 0.013). CONCLUSIONS: We found high CoRE prevalence in malaria patients as determined by serology in the study region; cases were associated with a worse clinical outcome. Further prospective studies with samples from different infection sites and the use of molecular tools are needed to determine the clinical significance of these findings.
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Vírus Chikungunya , Coinfecção , Dengue , Hepatite C , Leptospirose , Malária Falciparum , Malária Vivax , Malária , Humanos , Dengue/epidemiologia , Coinfecção/epidemiologia , Estudos Soroepidemiológicos , Estudos Transversais , Estudos Prospectivos , Venezuela/epidemiologia , Malária/epidemiologia , Malária/diagnóstico , Malária Vivax/epidemiologia , Vírus da Hepatite B , Imunoglobulina MRESUMO
BACKGROUND: Malaria-endemic areas are not spared from the impact of coronavirus disease 2019 (COVID-19), leading to co-infection scenarios where overlapping symptoms impose serious diagnostic challenges. Current knowledge on Plasmodium spp. and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infection in pregnant women remains limited, especially in Latin America, where Plasmodium vivax infection is highly prevalent. METHODS: This is a case series of five pregnant women with P. vivax and SARS-CoV-2 co-infection hospitalized in two main malaria referral centers of the Capital District and Bolivar state, Venezuela between March 13, 2020 and December 31, 2021. RESULTS: Clinical and laboratory data from five pregnant women with a mean age of 22 years were analyzed; three of them were in the third trimester of pregnancy. Comorbidities included obesity in two cases, hypertension in one, and asthma in one. Three out of five patients had severe to critical COVID-19 disease. Dry cough, fever, chills, and headache were the most frequent symptoms reported. Laboratory analyses showed elevated aspartate/alanine aminotransferase and creatinine levels, thrombocytopenia, and severe anemia as the most relevant abnormalities. The mean period between symptom onset and a positive molecular test for SARS-CoV-2 infection or positive microscopy for Plasmodium spp. was 4.8 ± 2.5 days and 2.8 ± 1.6 days, respectively. The mean hospital stay was 5.4 ± 7 days. Three women recovered and were discharged from the hospital. Two women died, one from cerebral malaria and one from respiratory failure. Three adverse fetal outcomes were registered, two miscarriages and one stillbirth. CONCLUSION: This study documented a predominance of severe/critical COVID-19 disease and a high proportion of adverse maternal-fetal outcomes among pregnant women with malaria and COVID-19 co-infection. More comprehensive prospective cohort studies are warranted to explore the risk factors, management challenges, and clinical outcomes of pregnant women with this co-infection.
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Aborto Espontâneo , COVID-19 , Coinfecção , Malária Vivax , Malária , Complicações Infecciosas na Gravidez , Feminino , Humanos , Gravidez , Adulto Jovem , Coinfecção/diagnóstico , Coinfecção/epidemiologia , COVID-19/diagnóstico , COVID-19/epidemiologia , Malária Vivax/diagnóstico , Malária Vivax/epidemiologia , Plasmodium vivax , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/epidemiologia , Gestantes , Estudos Prospectivos , SARS-CoV-2 , Venezuela/epidemiologiaRESUMO
Malaria during pregnancy is a major global health problem caused by infection with Plasmodium falciparum parasites. Severe effects arise from the accumulation of infected erythrocytes in the placenta. Here, erythrocytes infected by late blood-stage parasites adhere to placental chondroitin sulphate A (CS) via VAR2CSA-type P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. Immunity to placental malaria is acquired through exposure and mediated through antibodies to VAR2CSA. Through evolution, the VAR2CSA proteins have diversified in sequence to escape immune recognition but retained their overall macromolecular structure to maintain CS binding affinity. This structural conservation may also have allowed development of broadly reactive antibodies to VAR2CSA in immune women. Here we show the negative stain and cryo-EM structure of the only known broadly reactive human monoclonal antibody, PAM1.4, in complex with VAR2CSA. The data shows how PAM1.4's broad VAR2CSA reactivity is achieved through interactions with multiple conserved residues of different sub-domains forming conformational epitope distant from the CS binding site on the VAR2CSA core structure. Thus, while PAM1.4 may represent a class of antibodies mediating placental malaria immunity by inducing phagocytosis or NK cell-mediated cytotoxicity, it is likely that broadly CS binding-inhibitory antibodies target other epitopes at the CS binding site. Insights on both types of broadly reactive monoclonal antibodies may aid the development of a vaccine against placental malaria.
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Malária Falciparum , Malária , Humanos , Feminino , Gravidez , Antígenos de Protozoários , Malária Falciparum/parasitologia , Epitopos , Anticorpos Antiprotozoários , Anticorpos Monoclonais , Microscopia Crioeletrônica , Placenta/metabolismo , Plasmodium falciparum/metabolismo , Eritrócitos/parasitologia , Sulfatos de Condroitina/metabolismoRESUMO
For the first time, structural analogues to bisphenol A were investigated in infant formulas marketed in Brazil. A fast and high throughput UPLC-MS/MS method was established for simultaneous analysis of bisphenol A, B, E, F, and S in complex infant formula matrices. The influence of mobile phase composition on electrospray ionization response in negative mode was studied to improve the detectability of the method. As also, the main sample preparation variables that could affect the extraction and cleanup were screened by the Plackett-Burman design. The method performance characteristics were adequate, including reliable limits of detection (5-10 µg kg-1) and quantification (10-20 µg kg-1) with suitable recoveries (84.2-108.9 %) and precision (≤18 %). Sixty-one infant formulas were analyzed, and 36 % of total samples contained at least one bisphenol analogue, whose levels ranged between 10.9 and 198.9 µg kg-1. Based on a deterministic approach, the estimated daily intakes for babies up to 6 months old, fed exclusively with infant formula, were below the temporary tolerable daily intake of 4 µg kg-1 body weight set for bisphenol A by the European Food Safety Authority.
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Fórmulas Infantis , Espectrometria de Massas em Tandem , Compostos Benzidrílicos , Brasil , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Exposição Dietética , Humanos , Lactente , Fórmulas Infantis/química , FenóisRESUMO
In vitro culture of asexual blood stages of Plasmodium falciparum is essential to study the parasite biology, and several aspects need to be addressed to successfully cultivate the parasites, including the requirements for red blood cells and specific nutrients. Since Trager and Jensen established the technique in 1976, some modifications have been introduced to improve the growth rate and yield. In brief, the method is based on the use of human red blood cells suspended in RPMI-1640 culture medium supplemented with a source of lipids and maintained at 37 °C in a low-oxygen atmosphere. In this protocol, a description of thawing, culturing, and cryopreservation of asexual blood stages of P. falciparum is presented.
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Malária Falciparum , Plasmodium falciparum , Meios de Cultura , Eritrócitos/parasitologia , Humanos , Malária Falciparum/parasitologiaRESUMO
Plasmodium falciparum expresses a broad range of proteins on the surface of infected erythrocytes (IEs), including members of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. This protocol describes an immunomagnetic selection method using PfEMP1-specific antibodies to obtain a parasite clone homogenously expressing a particular PfEMP1 protein. The expression of the corresponding PfEMP1 is later tested by flow cytometry, and the selected parasites can be used for further analysis.
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Malária Falciparum , Plasmodium falciparum , Anticorpos Antiprotozoários , Antígenos de Protozoários , Eritrócitos/metabolismo , Citometria de Fluxo , Humanos , Malária Falciparum/parasitologia , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/genéticaRESUMO
Cultures of Plasmodium falciparum often contain a heterogeneous parasite population. However, several studies require analysis of single infected erythrocytes (IEs) or a clonal parasite population derived from a single parasite. This protocol describes an efficient method for cloning by using fluorescence-activated cell sorting (FACS). For this, an antibody for a particular IEs surface protein it is added to the cell mixture to separate positive and negative IEs for that marker. After the separation, the viable homogeneous population can be used to grow in culture or for molecular analysis.
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Malária Falciparum , Parasitos , Animais , Eritrócitos/metabolismo , Humanos , Malária Falciparum/parasitologia , Parasitos/metabolismo , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismoRESUMO
Several members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family can bind human serum proteins such as IgM and α2-macroglobulin (α2M). This binding seems to play a role in pathogenesis and immune evasion by improving the avidity of PfEMP1-mediated binding to erythrocyte receptors and/or by masking antibody epitopes in PfEMP1. In this protocol, we describe a flow cytometry-based protocol to evaluate IgM- and α2M-binding to intact and unfixed mature-stage IEs. The method can be used for laboratory clones and field isolates.
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Malária Falciparum , alfa 2-Macroglobulinas Associadas à Gravidez , Anticorpos Antiprotozoários , Eritrócitos/metabolismo , Feminino , Citometria de Fluxo , Humanos , Imunoglobulina M , Plasmodium falciparum/metabolismo , Gravidez , alfa 2-Macroglobulinas Associadas à Gravidez/metabolismo , Proteínas de Protozoários/metabolismoRESUMO
INTRODUCTION: Caustic agents, also called corrosive agents, could be acids or alkali in nature. If ingested, these agents can injure any part of the aerodigestive tree. Extent of injury depends on the type, concentration, duration of exposure and volume of caustic agent ingested. Serious complications after caustic agent ingestion can occur both in the short term such as hollow viscus perforation and death and in the long term such as stricture formation causing obstruction and lifetime risk of development of carcinoma. PRESENTATION OF A CASE: This is a case of a 25-year-old female who ingested an unknown substance resulting to a severe stricture of the larynx, hypopharynx, esophagus and pyloroantral region of the stomach. Six months after her tracheostomy and tube jejunostomy, she sought further medical attention in our institution due to inability to swallow food and saliva. She underwent pharyngolaryngectomy (PL) with the strictured esophagus and stomach left in-situ due to extensive adhesions. The subcutaneous colonic interposition reestablished the alimentary continuity by providing enough length for tension-free anastomosis and a more direct route for cervical anastomosis. DISCUSSION: Stricture formation is one of the most challenging late complication of corrosive injury. It results from scar formation in response to inflammation of the aerodigestive tract. Key factors in managing caustic strictures include safety of strictured segment resection, choice of replacement organ for reconstruction and route of conduit. CONCLUSION: Timing of surgery and proper selection the surgical procedure for complications of caustic ingestion can result in excellent long term outcomes.
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IgG antibodies are key effector molecules in acquired immunity to Plasmodium falciparum malaria, and the PfEMP1 adhesins expressed on the surface of the infected erythrocytes are crucial immunological targets. The antigen specificity of these antibodies has therefore been a major research focus. However, we recently reported that the Fc domain of naturally induced PfEMP1-specific IgG1 is selectively modified by post-translational omission of fucose from the conserved Fc glycan. The resulting afucosylated IgG has increased affinity for the IgG-Fc-receptor III family (FcγRIII), found on natural killer cells and on subsets of other cells in the immune system. We discuss the implications of these findings for the basic understanding of antimalarial immunity and for the design of improved vaccines against the disease.
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Antígenos de Protozoários , Malária Falciparum , Imunidade Adaptativa , Anticorpos Antiprotozoários , Eritrócitos , Humanos , Imunoglobulina G , Plasmodium falciparum , Proteínas de ProtozoáriosRESUMO
Hemoglobin C is the second most common structural hemoglobinopathy in Africa, and carriers have a reduced risk of severe malaria. However, the effect of HbAC on the antibody response to malaria antigens in pregnancy has not been studied. Here, we measured PfEMP1-specific antibodies in plasma samples from 74 Beninese pregnant women with either HbAA or HbAC. IgG-mediated inhibition of VAR2CSA+ infected erythrocytes adhesion to chondroitin sulfate A (CSA) was also tested. PfEMP1-specific IgG levels to VAR2CSA were significantly lower in HbAC women, suggesting less exposure to VAR2CSA. In contrast, the percentage of VAR2CSA+-infected erythrocytes adhesion to CSA was not different between HbAA and HbAC women. Moreover, IgG levels to PfEMP1 variants associated with severe malaria were not significantly different between groups. The findings indicate similar exposure to Plasmodium falciparum parasites expressing PfEMP1 variants causing severe malaria, and justify more comprehensive studies of hemoglobinopathy-related qualitative and quantitative differences in PfEMP1-specific antibody responses.
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Hemoglobinopatias , Malária Falciparum , Complicações Parasitárias na Gravidez , Anticorpos Antiprotozoários , Formação de Anticorpos , Antígenos de Protozoários , Eritrócitos/parasitologia , Feminino , Hemoglobina C/genética , Humanos , Imunoglobulina G , Malária Falciparum/parasitologia , Placenta/parasitologia , Plasmodium falciparum , Gravidez , Complicações Parasitárias na Gravidez/parasitologia , GestantesRESUMO
BACKGROUND: Sickle cell trait (HbAS) protects against severe Plasmodium falciparum malaria but not against placental malaria (PM). In this study, P falciparum erythrocyte membrane protein (PfEMP1)-specific antibodies were measured in HbAA and HbAS Beninese pregnant women as a proxy of exposure to specific PfEMP1 variants. METHODS: Plasma samples collected at delivery from 338 HbAA and 63 HbAS women were used to measure immunoglobulin (Ig)G levels to 6 recombinant PfEMP1 proteins and 3 corresponding native proteins expressed on the infected erythrocyte (IE) surface. Immunoglobulin G-mediated inhibition of VAR2CSA+ IEs adhesion to chondroitin sulfate A (CSA) was also tested. RESULTS: Levels of PfEMP1-specific IgG were similar in the 2 groups, except for native IT4VAR09 on IEs, where IgG levels were significantly higher in HbAS women. Adjusted odds ratios for women with positive IgG to HB3VAR06 and PFD1235w suggest a lower risk of infection with these virulent variants among HbAS individuals. The percentage of IEs binding to CSA did not differ between HbAA and HbAS women, but it correlated positively with levels of anti-VAR2CSA and parity. Women with PM had lower levels of anti-VAR2CSA-specific IgG and lower IgG-mediated inhibition of IE adhesion to CSA. CONCLUSIONS: The findings support similar malaria exposure in HbAA and HbAS women and a lack of HbAS-dependent protection against placental infection among pregnant women.
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Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (FcγR) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to FcγRIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces FcγRIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria.