Serologic Response to Vaccine for COVID-19 in Patients with Hematologic Malignancy: A Prospective Cohort Study

BACKGROUND

Patients with hematological cancers have increased COVID-19 morbidity and mortality, and these patients show attenuated vaccine responses. This study aimed to characterize the longitudinal humoral immune responses to COVID-19 vaccination in patients with hematological malignancies.

PATIENTS AND METHODS

We conducted a prospective cohort study, collecting samples from March 2021 to July 2022, from patients seen at a cancer treatment center in London, Ontario, Canada, who met the following eligibility criteria: age ≥18 years, diagnosed with a hematological malignancy, recipient of a COVID-19 vaccine during the study period, and able to provide informed consent.

RESULTS

Median anti-S titers (MST) were 0.0, 64.0, and 680.5 U/mL following first (V1), second (V2), and third (V3) vaccine doses, respectively. Patients with lymphoid malignancies' response to vaccination was attenuated compared to myeloid malignancy patients after V2 and V3 (P < .001, P < .01). Active treatment was associated with lower antibody titers (MST 10) compared to treatment 12-24 months (MST 465, P = .04367) and >24 months (MST 1660.5, P = .0025) prior to vaccination. V3 significantly increased antibody titers compared to V2 for patients less than 3 months from treatment. Increasing age was associated with smaller antibody response following V2 (P < .05), but not following V3. Patients receiving anti-CD20 therapy did not demonstrate increased antibody titer levels after V3 (V2 MST 0, V3 MST 0; P > .05).

CONCLUSION

We report an attenuated serologic response to COVID-19 vaccination in our study population of patients with hematological malignancy. The immune response to vaccination was affected by patient age, diagnosis, treatment, and timing of treatment exposure.

Plasma proteome of Long-COVID patients indicates HIF-mediated vasculo-proliferative disease with impact on brain and heart function

AIMS

Long-COVID occurs after SARS-CoV-2 infection and results in diverse, prolonged symptoms. The present study aimed to unveil potential mechanisms, and to inform prognosis and treatment.

METHODS

Plasma proteome from Long-COVID outpatients was analyzed in comparison to matched acutely ill COVID-19 (mild and severe) inpatients and healthy control subjects. The expression of 3072 protein biomarkers was determined with proximity extension assays and then deconvoluted with multiple bioinformatics tools into both cell types and signaling mechanisms, as well as organ specificity.

RESULTS

Compared to age- and sex-matched acutely ill COVID-19 inpatients and healthy control subjects, Long-COVID outpatients showed natural killer cell redistribution with a dominant resting phenotype, as opposed to active, and neutrophils that formed extracellular traps. This potential resetting of cell phenotypes was reflected in prospective vascular events mediated by both angiopoietin-1 (ANGPT1) and vascular-endothelial growth factor-A (VEGFA). Several markers (ANGPT1, VEGFA, CCR7, CD56, citrullinated histone 3, elastase) were validated by serological methods in additional patient cohorts. Signaling of transforming growth factor-β1 with probable connections to elevated EP/p300 suggested vascular inflammation and tumor necrosis factor-α driven pathways. In addition, a vascular proliferative state associated with hypoxia inducible factor 1 pathway suggested progression from acute COVID-19 to Long-COVID. The vasculo-proliferative process predicted in Long-COVID might contribute to changes in the organ-specific proteome reflective of neurologic and cardiometabolic dysfunction.

CONCLUSIONS

Taken together, our findings point to a vasculo-proliferative process in Long-COVID that is likely initiated either prior hypoxia (localized or systemic) and/or stimulatory factors (i.e., cytokines, chemokines, growth factors, angiotensin, etc). Analyses of the plasma proteome, used as a surrogate for cellular signaling, unveiled potential organ-specific prognostic biomarkers and therapeutic targets.

Investigation of N,N,N-Trimethyl-L-alanyl-L-proline Betaine (TMAP) as a Biomarker of Kidney Function

Glomerular filtration rate (GFR) is the most widely used tool for the measurement of kidney function, but endogenous biomarkers such as cystatin C and creatinine have limitations. A previous metabolomic study revealed N,N,N-trimethyl-L-alanyl-L-proline betaine (TMAP) to be reflective of kidney function. In this study, we developed a quantitative LCMS assay for the measurement of TMAP and evaluated TMAP as a biomarker of GFR. An assay to measure TMAP was developed using liquid chromatography-mass spectrometry. After validation of the method, we applied it to plasma samples from three distinct kidney disease patient cohorts: nondialysis chronic kidney disease (CKD) patients, patients receiving peritoneal and hemodialysis, and living kidney donors. We investigated whether TMAP was conserved in other mammalian and nonmammalian species, by analyzing plasma samples from Wistar rats with diet-induced CKD and searching for putative matches to the m/z for TMAP and its known fragments in the raw sample data repository "Metabolomics Workbench". The assay can measure plasma TMAP at a lower limit of quantitation (100 ng/mL) with an interday precision and accuracy of 12.8 and 12.1%, respectively. In all three patient cohorts, TMAP concentrations are significantly higher in patients with CKD than in controls with a normal GFR. Further, TMAP concentrations are also elevated in rats with CKD and TMAP is present in the sap produced from Acer saccharum trees. TMAP concentration is inversely related to GFR suggesting that it is a marker of kidney function. TMAP is present in nonmammalian species suggesting that it is part of a biologically conserved process.

Organ and cell-specific biomarkers of Long-COVID identified with targeted proteomics and machine learning

BACKGROUND

Survivors of acute COVID-19 often suffer prolonged, diffuse symptoms post-infection, referred to as "Long-COVID". A lack of Long-COVID biomarkers and pathophysiological mechanisms limits effective diagnosis, treatment and disease surveillance. We performed targeted proteomics and machine learning analyses to identify novel blood biomarkers of Long-COVID.

METHODS

A case-control study comparing the expression of 2925 unique blood proteins in Long-COVID outpatients versus COVID-19 inpatients and healthy control subjects. Targeted proteomics was accomplished with proximity extension assays, and machine learning was used to identify the most important proteins for identifying Long-COVID patients. Organ system and cell type expression patterns were identified with Natural Language Processing (NLP) of the UniProt Knowledgebase.

RESULTS

Machine learning analysis identified 119 relevant proteins for differentiating Long-COVID outpatients (Bonferonni corrected P < 0.01). Protein combinations were narrowed down to two optimal models, with nine and five proteins each, and with both having excellent sensitivity and specificity for Long-COVID status (AUC = 1.00, F1 = 1.00). NLP expression analysis highlighted the diffuse organ system involvement in Long-COVID, as well as the involved cell types, including leukocytes and platelets, as key components associated with Long-COVID.

CONCLUSIONS

Proteomic analysis of plasma from Long-COVID patients identified 119 highly relevant proteins and two optimal models with nine and five proteins, respectively. The identified proteins reflected widespread organ and cell type expression. Optimal protein models, as well as individual proteins, hold the potential for accurate diagnosis of Long-COVID and targeted therapeutics.

Elevated vascular transformation blood biomarkers in Long-COVID indicate angiogenesis as a key pathophysiological mechanism

BACKGROUND

Long-COVID is characterized by prolonged, diffuse symptoms months after acute COVID-19. Accurate diagnosis and targeted therapies for Long-COVID are lacking. We investigated vascular transformation biomarkers in Long-COVID patients.

METHODS

A case-control study utilizing Long-COVID patients, one to six months (median 98.5 days) post-infection, with multiplex immunoassay measurement of sixteen blood biomarkers of vascular transformation, including ANG-1, P-SEL, MMP-1, VE-Cad, Syn-1, Endoglin, PECAM-1, VEGF-A, ICAM-1, VLA-4, E-SEL, thrombomodulin, VEGF-R2, VEGF-R3, VCAM-1 and VEGF-D.

RESULTS

Fourteen vasculature transformation blood biomarkers were significantly elevated in Long-COVID outpatients, versus acutely ill COVID-19 inpatients and healthy controls subjects (P < 0.05). A unique two biomarker profile consisting of ANG-1/P-SEL was developed with machine learning, providing a classification accuracy for Long-COVID status of 96%. Individually, ANG-1 and P-SEL had excellent sensitivity and specificity for Long-COVID status (AUC = 1.00, P < 0.0001; validated in a secondary cohort). Specific to Long-COVID, ANG-1 levels were associated with female sex and a lack of disease interventions at follow-up (P < 0.05).

CONCLUSIONS

Long-COVID patients suffer prolonged, diffuse symptoms and poorer health. Vascular transformation blood biomarkers were significantly elevated in Long-COVID, with angiogenesis markers (ANG-1/P-SEL) providing classification accuracy of 96%. Vascular transformation blood biomarkers hold potential for diagnostics, and modulators of angiogenesis may have therapeutic efficacy.

COVID-19 vaccine humoral response and treatment effect in patients with hematologic malignancy

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Background: Patients with hematologic malignancies have a lower vaccine response and higher rates for SARS CoV-2 morbidity and mortality. We present preliminary data focusing on humoral vaccine responses and correlates with disease subtype and treatment exposure. Methods: We analyzed data from 332 patients with a hematologic malignancy from May 1, 2021 – Jan 31, 2022 who received SARS-CoV-2 vaccination and performed a prospective cohort serologic study with the Elecsys® Anti-SARS-CoV-2-S test. Patients received homologous or heterologous vaccine combination of BNT162b2, mRNA1273, ChAdOx1 nCoV-19, and/or Ad26.COV2.S. Blood samples were obtained before any vaccination, 2-6 weeks after the second vaccine (2V), before third vaccine (3V), and 2-6 weeks after 3V. Results: The median age was 67 years (range 18-91years) with 41.9% female. At 2V, 11.5% and at 3V, 23.8% received heterologous vaccines. Treatment status at first vaccine dose significantly affected peak 2V antibody response (p < 0.05). Seropositive rate and median antibody titer after 2V for previously untreated patients were higher compared to patients on active therapy or had previously been treated. Treatment naïve (n = 60; seropositivity 85.1%; median titer 1306 U/mL; [Q1-Q3:11.4- > 2499]); first-line (1L) active therapy (n = 127;65.4%; 41.25 U/mL; [ < 0.8-592.5]); second-line and beyond (2L+) active therapy (n = 56; 60.7%; 2.6U/mL; [ < 0.8-154]); previous treatment with 1L (n = 66;64.8%; 118 U/mL; [ < 0.8- > 2499]); previous treatment with 2L+ (n = 23; 59.1%; 4U/mL; [ < 0.8-229.5]). Of 61 patients that were seronegative at 2V, 17 (27.9%) seroconverted after 3V. Anti-CD20 monoclonal antibody (mAb) containing therapy as the most recent treatment from 2V had the greatest impact on humoral response. Exposure to anti-CD20 mAb based regimens or as monotherapy revealed low antibody responses (n = 84; seropositivity 22.6%; median titer < 0.8 U/mL; Q1-Q3 [ < 0.8- < 0.8]). On analysis of indolent B-cell Non-Hodgkin Lymphomas whereby antiCD-20 mAb are often incorporated, treatment proximity to 2V impacted responses: < 3 months (n = 33; 22%; < 0.8 U/mL; [ < 0.8- < 0.8]) vs. 12-24 months (n = 4; 60%; 228 U/mL; [ < 0.8-232]). In contrast, tyrosine kinase inhibitor (n = 38; 100%; 858 U/mL; [221- > 2499]), proteosome inhibitor monotherapy (n = 4;100%; median titer 1520 U/mL; [462- > 2499]) were among the subgroups with the highest numerical responses, however, the addition of corticosteroids impacted vaccine response as seen in proteosome inhibitor with corticosteroids (n = 7; 85.7%; 6.6 U/mL; [1.8-115.2]). Conclusions: The humoral response from our single institution cohort identifies diminished responses depending on treatment status and the type of treatment including the proximity of treatment exposure to receipt of vaccination. Furthermore, vaccine boosters can induce antibody responses in patients who were previously seronegative.

Epitope-specific antibody responses differentiate COVID-19 outcomes and variants of concern

BACKGROUNDThe role of humoral immunity in COVID-19 is not fully understood, owing, in large part, to the complexity of antibodies produced in response to the SARS-CoV-2 infection. There is a pressing need for serology tests to assess patient-specific antibody response and predict clinical outcome.METHODSUsing SARS-CoV-2 proteome and peptide microarrays, we screened 146 COVID-19 patients' plasma samples to identify antigens and epitopes. This enabled us to develop a master epitope array and an epitope-specific agglutination assay to gauge antibody responses systematically and with high resolution.RESULTSWe identified linear epitopes from the spike (S) and nucleocapsid (N) proteins and showed that the epitopes enabled higher resolution antibody profiling than the S or N protein antigen. Specifically, we found that antibody responses to the S-811-825, S-881-895, and N-156-170 epitopes negatively or positively correlated with clinical severity or patient survival. Moreover, we found that the P681H and S235F mutations associated with the coronavirus variant of concern B.1.1.7 altered the specificity of the corresponding epitopes.CONCLUSIONEpitope-resolved antibody testing not only affords a high-resolution alternative to conventional immunoassays to delineate the complex humoral immunity to SARS-CoV-2 and differentiate between neutralizing and non-neutralizing antibodies, but it also may potentially be used to predict clinical outcome. The epitope peptides can be readily modified to detect antibodies against variants of concern in both the peptide array and latex agglutination formats.FUNDINGOntario Research Fund (ORF) COVID-19 Rapid Research Fund, Toronto COVID-19 Action Fund, Western University, Lawson Health Research Institute, London Health Sciences Foundation, and Academic Medical Organization of Southwestern Ontario (AMOSO) Innovation Fund.

Rapid and accurate agglutination-based testing for SARS-CoV-2 antibodies

We have developed a rapid, accurate, and cost-effective serologic test for SARS-CoV-2 virus, which caused the COVID-19 pandemic, on the basis of antibody-dependent agglutination of antigen-coated latex particles. When validated using plasma samples that are positive or negative for SARS-CoV-2, the agglutination assay detected antibodies against the receptor-binding domain of the spike (S-RBD) or the nucleocapsid protein of SARS-CoV-2 with 100% specificity and ∼98% sensitivity. Furthermore, we found that the strength of the S-RBD antibody response measured by the agglutination assay correlated with the efficiency of the plasma in blocking RBD binding to the angiotensin-converting enzyme 2 in a surrogate neutralization assay, suggesting that the agglutination assay might be used to identify individuals with virus-neutralizing antibodies. Intriguingly, we found that >92% of patients had detectable antibodies on the day of a positive viral RNA test, suggesting that the agglutination antibody test might complement RNA testing for the diagnosis of SARS-CoV-2 infection.

Rapid COVID-19 testing: Speed, quality and cost. Can you have all three?

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Consider safety precautions and infection control processes, particularly in remote testing locations when using rapid SARS-CoV-2 devices.

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Seek oversight and partnership with an accredited clinical laboratory for guidance on setting up a quality assurance framework.

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Rapid-testing for SARS-CoV-2 requires method verification prior to clinical implementation.

Quality assurance practices for point of care testing programs: Recommendations by the Canadian society of clinical chemists point of care testing interest group

Point of Care Testing (POCT) refers to clinical laboratory testing performed outside the central laboratory, nearer to the patient and sometimes at the patient bedside. The testing is usually performed by clinical staff, such as physicians or nurses, who are not laboratory trained. This document was developed by the POCT Interest group of the Canadian Society of Clinical Chemists (CSCC) as practical guidance for quality assurance practices related to POCT performed in hospital and outside hospital environments. The aspects of quality assurance addressed in this document include: (1) device selection, (2) initial device verification, (3) ongoing device verification, (4) ongoing quality assurance including reagent and quality control (QC) lot changes, and (5) quality management including operator and document management.

Evaluation of electrochemiluminescence immunoassays for immunosuppressive drugs on the Roche cobas e411 analyzer

Background:  Therapeutic drug monitoring of immunosuppressant drugs are used to monitor drug efficacy and toxicity and to prevent organ transplant rejection. This study evaluates the analytical performance of semi-automated electrochemiluminescence immunoassays (ECLIA) for cyclosporine (CSA), tacrolimus (TAC) and sirolimus (SRL) on the Roche cobas e 411 analyzer at a major transplant hospital to assess method suitability and limitations.

Methods: Residual whole blood samples from patients undergoing immunosuppressant therapy were used for evaluation. Imprecision, linearity, functional sensitivity, method comparisons and lot-to-lot comparisons were assessed.

Results: Total imprecision ranged from 3.3 to 7.1% for CSA, 3.9 to 9.4% for TAC, and 4.6 to 8.2% for SRL. Linearity was verified from 30.0 to 960.9 μg/L for CSA, from 1.1 to 27.1 μg/L for TAC, and from 0.5 to 32.3 µg/L for SRL. The functional sensitivity met the manufacturer’s claims and was determined to be <6.5 μg/L for CSA, 1.1 μg/L for TAC, and <0.1 µg/L for SRL (CV≤20%). Deming regression analysis of method comparisons with the ARCHITECT immunoassay yielded slopes of 0.917 (95%CI: 0.885-0.949) and r of 0.985 for CSA, 0.938 (95%CI: 0.895-0.981) and r of 0.974 for TAC, and 0.842 (0.810-1.110) and r of 0.982 for SRL. Deming regression analysis of comparisons with the LC–MS/MS method yielded slopes of 1.331 (95%CI: 1.167-1.496) and r of 0.969 for CSA, 0.924 (95%CI: 0.843-1.005) and r of 0.984 for TAC, and 0.971 (95%CI: 0.913-1.030) and r of 0.993 for SRL.

Conclusions: The cobas e 411 ECLIA for CSA, TAC, and SRL have acceptable precision, linearity, and functional sensitivity. The method comparisons correlated well with the ARCHITECT immunoassay and LC–MS/MS and is fit for therapeutic drug monitoring

Transport function and transcriptional regulation of a liver-enriched human organic anion transporting polypeptide 2B1 transcriptional start site variant

Human organic anion transporting polypeptide 2B1 (OATP2B1) is a membrane transporter that facilitates the cellular uptake of a number of endogenous compounds and drugs. OATP2B1 is widely expressed in tissues including the small intestine, liver, kidney, placenta, heart, skeletal muscle, and platelets. It was recently shown that differential promoter usage in tissues results in expression of five OATP2B1 transcriptional start site variants that use distinct first exons but share common subsequent exons. These variants are expected to encode either a full-length (OATP2B1-FL) or shortened protein lacking 22 N terminus amino acids (OATP2B1-Short). Little is known regarding the transport activity and regulation of OATP2B1 variants with N terminus truncation. Here, using absolute quantitative polymerase chain reaction, we find the full-length variant is the major form expressed in duodenum but the short variant predominates in liver. Using a transient heterologous cell expression system, we find that the transport activities of the short OATP2B1 variant toward substrates estrone sulfate and rosuvastatin are similar to the well characterized full-length variant. Transcriptional activity screening of the liver-enriched OATP2B1 variant promoter identified hepatocyte nuclear factor 4 α (HNF4α) as a novel transacting factor. With a combination of in silico screening, promoter mutation in cell-based reporter assays, small interfering RNA knockdown, and chromatin immunoprecipitation (ChIP) studies, we identified a functional HNF4α binding site close to the transcription start site (-17 to -4 bp). We conclude that the major OATP2B1 protein form in liver is transport competent and its hepatic expression is regulated by HNF4α.

Clarifying the importance of CYP2C19 and PON1 in the mechanism of clopidogrel bioactivation and in vivo antiplatelet response

AIMS

It is thought that clopidogrel bioactivation and antiplatelet response are related to cytochrome P450 2C19 (CYP2C19). However, a recent study challenged this notion by proposing CYP2C19 as wholly irrelevant, while identifying paraoxonase-1 (PON1) and its Q192R polymorphism as the major driver of clopidogrel bioactivation and efficacy. The aim of this study was to systematically elucidate the mechanism and relative contribution of PON1 in comparison to CYP2C19 to clopidogrel bioactivation and antiplatelet response.

METHODS AND RESULTS

First, the influence of CYP2C19 and PON1 polymorphisms and plasma paraoxonase activity on clopidogrel active metabolite (H4) levels and antiplatelet response was assessed in a cohort of healthy subjects (n = 21) after administration of a single 75 mg dose of clopidogrel. There was a remarkably good correlation between H4 AUC (0-8 h) and antiplatelet response (r2 = 0.78). Furthermore, CYP2C19 but not PON1 genotype was predictive of H4 levels and antiplatelet response. There was no correlation between plasma paraoxonase activity and H4 levels. Secondly, metabolic profiling of clopidogrel in vitro confirmed the role of CYP2C19 in bioactivating clopidogrel to H4. However, heterologous expression of PON1 in cell-based systems revealed that PON1 cannot generate H4, but mediates the formation of another thiol metabolite, termed Endo. Importantly, Endo plasma levels in humans are nearly 20-fold lower than H4 and was not associated with any antiplatelet response.

CONCLUSION

Our results demonstrate that PON1 does not mediate clopidogrel active metabolite formation or antiplatelet action, while CYP2C19 activity and genotype remains a predictor of clopidogrel pharmacokinetics and antiplatelet response.

The human proton-coupled folate transporter (hPCFT): modulation of intestinal expression and function by drugs

Folic acid is a vitamin essential for thymidylate and purine synthesis. The human proton-coupled folate transporter (hPCFT) has recently been identified as a pH-dependent folic acid transporter, and mutations in this transporter have been linked to hereditary folic acid malabsorption. In this study, we assessed hPCFT-mediated transport activity in vitro, intersubject variability of intestinal expression in relation to blood folates, and the relationship of proton-pump inhibitor (PPI) therapy on hPCFT expression in vivo. We created a Madin-Darby canine kidney strain II (MDCKII) cell line stably expressing hPCFT to evaluate its drug substrates and inhibitors. Intestinal pinch biopsies (duodenum, ileum, colon) were collected from patients undergoing routine endoscopy procedures, and expressed levels of hPCFT were determined by RT-PCR. When assessed using MDCKII-hPCFT cells, folic acid and methotrexate were found to be high-affinity hPCFT substrates. Sulfasalazine and pyrimethamine were noted to inhibit hPCFT activity with Ki values of 42.3 and 161.7 micromol/l, respectively. hPCFT was localized to the brush-border membrane of enterocytes with highest expression in the duodenum and reduced levels in the ileum and colon. When we assessed hPCFT expression in a subset of patients who were receiving PPI therapy, a near 50% reduction in duodenal hPCFT mRNA expression was noted. These results suggest that hPCFT transporter activity can be modulated by many drugs in clinical use, and expression of this transporter in the gastrointestinal tract is higher in the duodenum than more distal sites (duodenum > ileum > colon). Importantly, we note that PPI drug use appears to be associated with reduced hPCFT expression in vivo.

Human skeletal muscle drug transporters determine local exposure and toxicity of statins

RATIONALE

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, are important drugs used in the treatment and prevention of cardiovascular disease. Although statins are well tolerated, many patients develop myopathy manifesting as muscle aches and pain. Rhabdomyolysis is a rare but severe toxicity of statins. Interindividual differences in the activities of hepatic membrane drug transporters and metabolic enzymes are known to influence statin plasma pharmacokinetics and risk for myopathy. Interestingly, little is known regarding the molecular determinants of statin distribution into skeletal muscle and its relevance to toxicity.

OBJECTIVE

We sought to identify statin transporters in human skeletal muscle and determine their impact on statin toxicity in vitro.

METHODS AND RESULTS

We demonstrate that the uptake transporter OATP2B1 (human organic anion transporting polypeptide 2B1) and the efflux transporters, multidrug resistance-associated protein (MRP)1, MRP4, and MRP5 are expressed on the sarcolemmal membrane of human skeletal muscle fibers and that atorvastatin and rosuvastatin are substrates of these transporters when assessed using a heterologous expression system. In an in vitro model of differentiated, primary human skeletal muscle myoblast cells, we demonstrate basal membrane expression and drug efflux activity of MRP1, which contributes to reducing intracellular statin accumulation. Furthermore, we show that expression of human OATP2B1 in human skeletal muscle myoblast cells by adenoviral vectors increases intracellular accumulation and toxicity of statins and such effects were abrogated when cells overexpressed MRP1.

CONCLUSIONS

These results identify key membrane transporters as modulators of skeletal muscle statin exposure and toxicity.