SARS-CoV-2 seroprevalence among healthcare workers in a highly vaccinated Japanese medical center from 2020-2023.

Infection-induced SARS-CoV-2 seroprevalence has been studied worldwide. At Juntendo University Hospital (JUH) in Tokyo, Japan, we have consistently conducted serological studies using the blood residue of healthcare workers (HCWs) at annual health examinations since 2020. In this 2023 study (n = 3,594), N-specific seroprevalence (infection-induced) was examined while univariate and multivariate logistic regression analyses were performed to compute ORs of seroprevalence with respect to basic characteristics of participants. We found that the N-specific seroprevalence in 2023 was 54.1%-a jump from 17.7% in 2022, and 1.6% in 2021-with 37.9% as non-PCR-confirmed asymptomatic infection cases. Those younger than 50 (adjusted OR = 1.62; p < .001) and recipients with 4 doses or less of vaccine had a higher risk to be N-positive, ranging from 1.45 times higher for the participants with 4 doses (p < .001) to 4.31 times higher for the participants with 1 dose (p < .001), compared to those with 5 or more doses. Our findings indicate that robust vaccination programs may have helped alleviate symptoms but consequently caused asymptomatic spread in this hospital, especially among younger HCWs. Although having four doses or less was found to be associated with higher risk of infection, the optimal constitution and intervals for effective booster vaccines warrant further investigations.

Downregulation of osteoprotegerin in colorectal cancer cells promotes liver metastasis via activating tumor-associated macrophage.

Osteoprotegerin (OPG) is a secreted cytokine that functions as a decoy receptor for receptor activator of nuclear factor kappa-B (RANK) ligand (RANKL). Anti-RANKL treatment for bone metastasis has been widely accepted for solid tumors. However, the mechanism of OPG-RANKL-RANK signaling in systemic colorectal cancer (CRC) metastasis remains unclear. In this study, we investigated the relevance and function of OPG expression in CRC liver metastasis. First, we performed in silico analysis using The Cancer Genome Atlas public database and found that lower OPG expression in CRC was associated with poor overall survival. Immunohistochemistry analyses using resected specimen from patients with CRC in our institute confirmed the result. Patient-matched primary CRC and liver metastases showed a significant downregulation of OPG expression in metastatic lesions. In CRC cell lines, OPG expression did not suppress cell proliferation and migration. However, OPG expression inhibited macrophage migration by suppressing the RANKL-RANK pathway. Moreover, in vivo mouse liver metastasis models showed that OPG expression in CRC cells suppressed liver metastases. In addition, treatment with an anti-RANKL neutralizing antibody also suppressed liver metastases. These results showed that downregulation of OPG expression in CRC cells promotes liver metastasis by activating tumor-associated macrophage, which can become a candidate for targeted therapy with anti-RANKL neutralizing antibody for CRC liver metastasis.

Assessment of antibody dynamics and neutralizing activity using serological assay after SARS-CoV-2 infection and vaccination.

The COVID-19 antibody test was developed to investigate the humoral immune response to SARS-CoV-2 infection. In this study, we examined whether S antibody titers measured using the anti-SARS-CoV-2 IgG II Quant assay (S-IgG), a high-throughput test method, reflects the neutralizing capacity acquired after SARS-CoV-2 infection or vaccination. To assess the antibody dynamics and neutralizing potency, we utilized a total of 457 serum samples from 253 individuals: 325 samples from 128 COVID-19 patients including 136 samples from 29 severe/critical cases (Group S), 155 samples from 71 mild/moderate cases (Group M), and 132 samples from 132 health care workers (HCWs) who have received 2 doses of the BNT162b2 vaccinations. The authentic virus neutralization assay, the surrogate virus neutralizing antibody test (sVNT), and the Anti-N SARS-CoV-2 IgG assay (N-IgG) have been performed along with the S-IgG. The S-IgG correlated well with the neutralizing activity detected by the authentic virus neutralization assay (0.8904. of Spearman's rho value, p < 0.0001) and sVNT (0.9206. of Spearman's rho value, p < 0.0001). However, 4 samples (2.3%) of S-IgG and 8 samples (4.5%) of sVNT were inconsistent with negative results for neutralizing activity of the authentic virus neutralization assay. The kinetics of the SARS-CoV-2 neutralizing antibodies and anti-S IgG in severe cases were faster than the mild cases. All the HCWs elicited anti-S IgG titer after the second vaccination. However, the HCWs with history of COVID-19 or positive N-IgG elicited higher anti-S IgG titers than those who did not have it previously. Furthermore, it is difficult to predict the risk of breakthrough infection from anti-S IgG or sVNT antibody titers in HCWs after the second vaccination. Our data shows that the use of anti-S IgG titers as direct quantitative markers of neutralizing capacity is limited. Thus, antibody tests should be carefully interpreted when used as serological markers for diagnosis, treatment, and prophylaxis of COVID-19.

Evaluation of bone marrow aspirates using the automated hematology analyzer Sysmex XN-3000.

INTRODUCTION: This study evaluated the feasibility of the Sysmex XN-3000 automated hematology analyzer for the assessment of total nucleated cells (TNC) and bone marrow (BM) cell density in routine bone marrow aspiration (BMA) samples. METHODS: A total of 54 BMA samples from 39 hematological patients were evaluated. The number of megakaryocytes was calculated by a specific gating algorithm using the body fluid mode of the WBC differential (WDF) channel. Lipid contents were calculated through a newly developed algorithm utilizing the WDF channel. The ratio of lipid particles over TNCs by the WNR channel was compared with the BM cellularity assessed by the BM biopsy. The myeloid/erythroid (M/E) ratio was calculated by measuring the number of myeloid cells in the WDF channel and the number of nucleated red blood cells (NRBCs) in the WNR channel. RESULTS: XN-3000 counts and microscopic results showed a linear correlation in TNC (R2  = .98, p < .001), megakaryocytes (R2  = .59, p = .002), NRBC (R2  = .84, p < .001), and M/E ratio (R2  = .59, p < .001). There were significant differences in the lipid/TNC ratios of hypercellular, normocellular, and hypocellular BMs measured by XN-3000 (p < .001). Receiver-operating characteristic analysis detected cut-off values of the lipid/TNC ratio of >0.4054 for hypoplasia and <0.157 for hyperplasia. The sensitivity and specificity for hypoplasia were 100% and 88%, and for hyperplasia were 89% and 86%, respectively. CONCLUSION: XN-3000 provides a quantitative assessment of BM cellularity, supporting the qualitative assessment by myelogram and BM biopsy.

Increased SARS-CoV-2 seroprevalence and spread of infection without awareness among healthcare workers through 2020-2022 in a Japanese medical center.

Despite Japan's high vaccination coverage, daily numbers of new COVID-19 cases have been high. However, studies on the seroprevalence among Japanese people and the causative factors for rapid spread have remained limited. In this study, we aimed to examine the seroprevalence and associated factors in healthcare workers (HCWs) of a medical center in Tokyo using blood samples drawn at annual check-ups from 2020 to 2022. We found that of the 3,788 HCWs in 2022 (by mid-June), 669 were seropositive for N-specific antibodies (tested by Roche Elecsys Anti-SARS-CoV-2 assay); the seroprevalence surged from 0.3% in 2020 and 1.6% in 2021 to 17.7% in 2022. Notably, our study found 325 (48.6%; 325/669) cases were infected without awareness. Among those with a previously PCR-confirmed SARS-CoV-2 infection during the past three years, 79.0% (282/357) were found after January 2022, after the Omicron variant was first detected in Tokyo at the end of 2021. This study indicates the fast spread of the SARS-CoV-2 among HCWs during the Omicron surge in Japan. The high percentage of infection without awareness may be a key driving factor causing rapid person-to-person transmission, as shown in this medical center with high vaccination coverage and strict infection control measures.

Performance evaluation of the Ortho VITROS SARS-CoV-2 Spike-Specific Quantitative IgG test by comparison with the surrogate virus neutralizing antibody test and clinical assessment.

BACKGROUND: Despite the worldwide campaigns of COVID-19 vaccinations, the pandemic is still a major medical and social problem. The Ortho VITROS SARS-CoV-2 spike-specific quantitative IgG (VITROS S-IgG) assay has been developed to assess neutralizing antibody (NT antibody) against SARS-CoV-2 spike (S) antibodies. However, it has not been evaluated in Japan, where the total cases and death toll are lower than the rest of the world. METHODS: The clinical performance of VITROS S-IgG was evaluated by comparing with the NT antibody levels measured by the surrogate virus neutralizing antibody test (sVNT). A total of 332 serum samples from 188 individuals were used. Of these, 219 samples were from 75 COVID-19 patients: 96 samples from 20 severe/critical cases (Group S), and 123 samples from 55 mild/moderate cases (Group M). The remaining 113 samples were from 113 healthcare workers who had received 2 doses of the BNT162b2 vaccine. RESULTS: VITROS S-IgG showed good correlation with the cPass sVNT assay (Spearman rho = 0.91). Both VITROS S-IgG and cPass sVNT showed significantly higher plateau levels of antibodies in Group S compared to Group M. Regarding the humoral immune responses after BNT162b2 vaccination, individuals who were negative for SARS-CoV-2 nucleocapsid (N)-specific antibodies had statistically lower titers of both S-IgG and sVNT compared to individuals with a history of COVID-19 and individuals who were positive for N-specific antibodies without history of COVID-19. In individuals who were positive for N-specific antibodies, S-IgG and sVNT titers were similar to individuals with a history of COVID-19. CONCLUSIONS: Although the automated quantitative immunoassay VITROS S-IgG showed a reasonable correlation with sVNT antibodies, there is some discrepancy between Vitros S-IgG and cPass sVNT in milder cases. Thus, VITROS S-IgG can be a useful diagnostic tool in assessing the immune responses to vaccination and herd immunity. However, careful analysis is necessary to interpret the results.

Bowel obstruction secondary to internal hernia in a hereditary angioedema patient: a case report.

BACKGROUND: Gastrointestinal attacks are frequent symptoms in patients diagnosed with hereditary angioedema (HAE). Cases of self-limited bowel intussusception and unneeded exploratory laparotomy due to lack of knowledge about HAE have been reported. Furthermore, after the introduction of C1-esterase inhibitor (C1-INH) concentrate, the recommended medication for HAE attacks, treatment has become typically medical in nature. We share a rare case where operative exploration was indicated to resolve a mechanical small bowel obstruction secondary to an HAE attack. CASE REPORT: An 80-year-old woman with HAE presented with lower left abdominal pain, vomiting, and nausea. Computed tomography (CT) showed edema of the small bowel and stomach as well as possible signs of mechanical small bowel obstruction. The patient was treated with C1-INH concentrate but showed only mild signs of relief, warranting diagnostic laparoscopy. Intraoperative findings showed internal herniation and strangulation of the small bowel caused by adhesions forming a band. After surgical intervention, no bowel resection was needed. CONCLUSION: Although C1-INH concentrate remains the principal treatment for HAE, gastrointestinal attacks may potentially cause surgical emergencies.

Causes of Thrombocytosis: A Single-center Retrospective Study of 1,202 Patients.

Objective Thrombocytosis can occur as a primary event accompanying hematological diseases or as a secondary event. Since the publication of the World Health Organization classification in 2008, thrombocytosis is now generally defined as a platelet count above 450×109/L. Furthermore, the discovery of driver-gene mutations in myeloproliferative neoplasms (MPNs) has simplified the diagnostic approach for thrombocytosis. To identify the causes of thrombocytosis using this new definition, we conducted a retrospective study. Methods We identified outpatients and inpatients aged 20 years or older with platelet counts >450×109/L in a half-year period at a single institute and analyzed the causes of thrombocytosis and associated clinical characteristics. Results Among 1,202 patients with thrombocytosis, 150 (12.5%) had primary and 999 (83.1%) had secondary thrombocytosis. Of these patients with primary thrombocytosis, 129 (86%) had at least 1 molecular marker indicative of MPNs. The major causes of secondary thrombocytosis were tissue injury (32.2%), infection (17.1%), chronic inflammatory disorders (11.7%) and iron deficiency anemia (11.1%). The median platelet count and the incidence of thrombosis were significantly higher in patients with primary thrombocytosis than in those with secondary thrombocytosis. Conclusion Thrombocytosis mainly occurs as a secondary event; however, it is important to determine the cause of and prevent thrombosis, particularly in cases of primary thrombocytosis.

Performance evaluation of the Roche Elecsys® Anti-SARS-CoV-2 immunoassays by comparison with neutralizing antibodies and clinical assessment.

Quantitative measurement of SARS-CoV-2 neutralizing antibodies is highly expected to evaluate immune status, vaccine response, and antiviral therapy. The Elecsys® Anti-SARS-CoV-2 S (Elecsys® anti-S) was developed to measure anti-SARS-CoV-2 S proteins. We sought to investigate whether Elecsys® anti-S can be used to predict neutralizing activities in patients' serums using an authentic virus neutralization assay. One hundred forty-six serum samples were obtained from 59 patients with COVID-19 at multiple time points. Of the 59 patients, 44 cases were included in Group M (mild 23, moderate 21) and produced 84 samples (mild 35, moderate 49), while 15 cases were included in Group S (severe 11, critical 4) and produced 62 samples (severe 43, critical 19). The neutralization assay detected 73% positive cases, and Elecsys® anti-S and Elecsys® Anti-SARS-CoV-2 (Elecsys® anti-N) showed 72% and 66% positive cases, respectively. A linear correlation between the Elecsys® anti-S assay and the neutralization assay were highly correlated (r = 0.7253, r2 = 0.5261) than a linear correlation between the Elecsys® anti-N and neutralization assay (r = 0.5824, r2 = 0.3392). The levels of Elecsys® anti-S antibody and neutralizing activities were significantly higher in Group S than in Group M after 6 weeks from onset of symptoms (p < 0.05). Conversely, the levels of Elecsys® anti-N were comparable in both groups. Three immunosuppressed patients, including cancer patients, showed low levels of anti-S and anti-N antibodies and neutralizing activities throughout the measurement period, indicating the need for careful follow-up. Our data indicate that Elecsys® anti-S can predict the neutralization antibodies in COVID-19.

Activation of SARS-CoV-2 neutralizing antibody is slower than elevation of spike-specific IgG, IgM, and nucleocapsid-specific IgG antibodies.

COVID-19 antibody testing has been developed to investigate humoral immune response in SARS-CoV-2 infection. To assess the serological dynamics and neutralizing potency following SARS-CoV-2 infection, we investigated the neutralizing (NT) antibody, anti-spike, and anti-nucleocapsid antibodies responses using a total of 168 samples obtained from 68 SARS-CoV-2 infected patients. Antibodies were measured using an authentic virus neutralization assay, the high-throughput laboratory measurements of the Abbott Alinity quantitative anti-spike receptor-binding domain IgG (S-IgG), semiquantitative anti-spike IgM (S-IgM), and anti-nucleocapsid IgG (N-IgG) assays. The quantitative measurement of S-IgG antibodies was well correlated with the neutralizing activity detected by the neutralization assay (r = 0.8943, p < 0.0001). However, the kinetics of the SARS-CoV-2 NT antibody in severe cases were slower than that of anti-S and anti-N specific antibodies. These findings indicate a limitation of using the S-IgG antibody titer, detected by the chemiluminescent immunoassay, as a direct quantitative marker of neutralizing activity capacity. Antibody testing should be carefully interpreted when utilized as a marker for serological responses to facilitate diagnostic, therapeutic, and prophylactic interventions.

Antibody response and seroprevalence in healthcare workers after the BNT162b2 vaccination in a University Hospital at Tokyo.

In 2020, we reported a low seroprevalence of N-specific antibodies in 4147 health care workers (HCWs) at a frontline hospital in Tokyo, Japan. In Japan, a vaccine campaign was launched in early 2021. We re-evaluated seroprevalences of N- and S-specific antibodies in 2202 HCWs who took two doses of the BNT162b2 vaccine. In 2021, N-specific seroprevalence remains as low as 1.59%. The seroprevalences were comparable among all HCWs regardless of exposure levels. Almost all of the HCWs elicited S-specific antibodies after vaccination. However, the HCWs who had COVID-19 elicited higher S-specific antibody titers than those who did not have COVID-19. In the HCWs without a history of COVID-19, 1.1% (23 out of 2185) were seropositive with N-specific antibodies, indicating the existence of asymptomatic infections. Also, S-specific antibody titers were higher in females and younger HCWs, and in those who had severe side effects. However, S-specific antibody titers were lower depending on the number of days after the second dose of vaccination specifically in elderly individuals. In conclusion, this study indicates N-specific seroprevalence remains low in HCWs at a frontline hospital in Tokyo. The mRNA vaccine elicited S-specific antibody in HCWs, however, the titers decreased as the days proceeded.

Force-dependent remodeling of cytoplasmic ZO-1 condensates contributes to cell-cell adhesion through enhancing tight junctions.

The physiological importance of biomolecular condensates is widely recognized, but how it is controlled in time and space during development is largely unknown. Here, we show that a tight junction protein ZO-1 forms cytoplasmic condensates in the trophectoderm (TE) of the mouse embryo before E4.0. These disappear via dissolution, and ZO-1 accumulates at the cell junction as the blastocyst cavity grows and internal pressure on TE cells increases. In contrast, this dissolution was less evident in TE cells attached to the inner cell mass because they receive weaker tensile forces. Furthermore, analyses using MDCK cells demonstrated that the ZO-1 condensates are generated and maintained by liquid-liquid phase separation. Our study also highlights that the dynamics of these condensates depends on the physical environment via an interaction between ZO-1 and F-actin. We propose that the force-dependent regulation of ZO-1 condensation contributes to the establishment of robust cell-cell adhesion during early development.

Laparoscopic posterior pelvic exenteration for clear cell adenocarcinoma arising in an episiotomy scar.

Malignant degeneration of endometriosis is a very rare event, especially when it develops in an episiotomy scar. A 53-year-old woman with an enlarged perineal mass presented to the hospital. She had undergone vaginal delivery with episiotomy twice. Imaging analyses showed a mass involving the levator ani muscle apart from the rectum, with lymph node metastases to the right inguinal and internal iliac regions. A biopsy specimen of the right inguinal lymph node revealed poorly differentiated adenocarcinoma. She underwent neoadjuvant chemotherapy according to the treatment strategy of anal fistula cancer. Laparoscopic posterior pelvic exenteration and pelvic lymph node dissection with anterior inguinal node dissection was performed, along with perineal reconstruction. Pathological examination revealed clear cell adenocarcinoma with lymph node metastases, derived from extrapelvic endometriosis in the episiotomy scar. She was treated with adjuvant chemotherapy according to the treatment strategy of vulvar cancer, and showed no evidence of recurrence after 15 months of surgery.

Clinical Evaluation of Siemens SARS-CoV-2 Total Antibody assay and IgG assay using the Dimension EXL 200 in the Tokyo Metropolitan area.

BACKGROUND: We evaluated the efficacy of the Siemens SARS-CoV-2 Total Antibody assay (CV2T) and IgG assay (CV2G) that can detect antibodies against the receptor binding domain of S antigen in patients with COVID-19 in a Tokyo metropolitan area. METHODS: Sensitivity and antibody levels were examined by CV2T and CV2G on Dimension EXL 200 using 236 serum samples obtained from 79 RT-PCR confirmed COVID-19 patients at multiple time points and were compared with disease severity by the World Health Organization criteria. The assay specificity was evaluated using samples collected before the COVID-19 pandemic. RESULTS: The sensitivity of CV2T and CV2G were low (16.7-21.4%) in days 0-6 and increased to 43.8-52.5% in days 7-13 and to 80.8-90.0% in days 14-20. The seroprevalences persisted after day 21 to days past 42 regardless of disease severity. In every day grouping, mean antibody levels were higher in severe cases than in mild cases with a significant difference in days 14-20 and days 20-27. The specificity was 97.9 % (95% CI; 92.8-99.8) for CV2T and 99.0 % (95% CI; 94.6-100) for CV2G. CONCLUSIONS: Our results indicate a high specificity and high sensitivity at 14 days of CV2T and CV2G as antibody detection assays.

Fibrinogen measurement by a novel point-of-care device with whole blood: comparison of values against Clauss method.

Timely fibrinogen replacement is key to treating critical hemorrhage. Measuring fibrinogen concentration by conventional laboratory tests requires centrifugation of blood samples and is often time-consuming. A point-of-care testing device (A&T, Yokohama, Japan), CG02N, has been available in Japan since 2011 to measure fibrinogen concentration without centrifugation. However, it has not been widely used as it requires dilution of blood samples using manual micropipetting. To further speed up and simplify the fibrinogen measurement, an improved device called FibCare (Atom Medical, Tokyo, Japan) was developed to avoid diluting blood samples. The purpose of this study is to verify the reliability of FibCare against laboratory measurement using the Clauss method. Fibrinogen concentrations with 60 sodium citrated whole blood samples were measured by both FibCare and Clauss methods in the laboratory. Measured values with the Clauss method were distributed in the 88-300 mg/dL range. By comparing these results, a significant positive correlation was observed between the FibCare and Clauss method (Y = 12.402 + 0.982 X; R = 0.891; P < 0.01). The study indicated that FibCare allows accurate measurement of fibrinogen concentration and shows a possibility to contribute to optimal fibrinogen replacement therapy during critical hemorrhage.

Accuracy study of a novel alternate method measuring erythrocyte sedimentation rate for prototype hematology analyzer Celltac α.

INTRODUCTION: The erythrocyte sedimentation rate (ESR) is a nonspecific inflammation indicator. In laboratory testing, automated ESR analyzers may use the reference Westergren method (Reference WG), modified Westergren (Modified WG), or Alternate ESR method (Alternate ESR) based on photometric rheology. A prototype hematology analyzer Celltac α+ (Nihon Kohden Corporation) with built-in Novel ESR analysis technology (Novel ESR) was developed to improve the accuracy of Alternate ESR. Alternate ESR uses only the aggregation phase information of Reference WG. The Novel ESR adds sedimentation and packing phase information obtained by hematology analyzer measurands. High correlation with WG was ensured by predicting the ESR value using Hematocrit (Hct) and MCV values as correcting parameters. METHODS: Novel ESR was compared with Modified WG (MONITOR-40, Joko Corporation) and Reference WG, according to internationally recognized guidelines: Precision, carryover, limit of quantification, comparability, linearity, accuracy, and fibrinogen sensitivity. Samples from healthy volunteers and clinical patients were used. The correction performance of Novel ESR and Modified WG was compared with Reference WG by regression analysis in three range categories for ESR and measurands affecting ESR correction (Hct, MCV, and MCH). RESULTS: Novel ESR showed sufficient basic performance and comparability with Modified WG. In the accuracy study comparing with Reference WG, the regression equation was y = 1.026x + 0.5(r =  .945,P <  .001;n = 271). When evaluating the correction performance, the slopes were within 0.8-1.2, except for the high part of Hct. All intercepts were within 10 mm. CONCLUSION: This study validated the correction performance to the initial estimated ESR value by aggregation phase information using information reflecting sedimentation and packing phase obtained from automated hematology analyzer. The Celltac α+ Novel ESR provided results equivalent to Reference WG.

SARS-CoV-2 seroprevalence in healthcare workers at a frontline hospital in Tokyo.

Healthcare workers (HCWs) are highly exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The actual coronavirus disease (COVID-19) situation, especially in regions that are less affected, has not yet been determined. This study aimed to assess the seroprevalence of SARS-CoV-2 in HCWs working in a frontline hospital in Tokyo, Japan. In this cross-sectional observational study, screening was performed on consented HCWs, including medical, nursing, and other workers, as part of a mandatory health checkup. The screening test results and clinical characteristics of the participants were recorded. The antibody seroprevalence rate among the 4147 participants screened between July 6 and August 21, 2020, was 0.34% (14/4147). There was no significant difference in the seroprevalence rate between frontline HCWs with a high exposure risk and HCWs working in other settings with a low exposure risk. Of those seropositive for SARS-CoV-2, 64% (9/14) were not aware of any symptoms and had not previously been diagnosed with COVID-19. In conclusion, this study provides insights into the extent of infection and immune status in HCWs in Japan, which has a relatively low prevalence of COVID-19. Our findings aid in formulating public health policies to control virus spread in regions with low-intensity COVID-19.

Comparison of the clinical performance and usefulness of five SARS-CoV-2 antibody tests.

We examined the usefulness of five COVID-19 antibody detection tests using 114 serum samples at various time points from 34 Japanese COVID-19 patients. We examined Elecsys Anti-SARS-CoV-2 from Roche, and four immunochromatography tests from Hangzhou Laihe Biotech, Artron Laboratories, Chil, and Nadal. In the first week after onset, Elecsys had 40% positivity in Group S (severe cases) but was negative in Group M (mild-moderate cases). The immunochromatography kits showed 40-60% and 0-8% positivity in Groups S and M, respectively. In the second week, Elecsys showed 75% and 50% positivity, and the immunochromatography tests showed 5-80% and 50-75% positivity in Groups S and M, respectively. After the third week, Elecsys showed 100% positivity in both groups. The immunochromatography kits showed 100% positivity in Group S. In Group M, positivity decreased to 50% for Chil and 75-89% for Artron and Lyher. Elecsys and immunochromatography kits had 91-100% specificity. Elecsys had comparable chronological change of cut-off index values in the two groups from the second week to the sixth week. The current SARS-CoV-2 antibody detection tests do not provide meaningful interpretation of severity and infection status. Its use might be limited to short-term epidemiological studies.

Suppressing neutrophil-dependent angiogenesis abrogates resistance to anti-VEGF antibody in a genetic model of colorectal cancer.

We tested cis-ApcΔ716/Smad4+/- and cis-ApcΔ716/Smad4+/-KrasG12D mice, which recapitulate key genetic abnormalities accumulating during colorectal cancer (CRC) tumorigenesis in humans, for responsiveness to anti-VEGF therapy. We found that even tumors in cis-ApcΔ716/Smad4+/-KrasG12D mice, although highly aggressive, were suppressed by anti-VEGF treatment. We tested the hypothesis that inflammation, a major risk factor and trigger for CRC, may affect responsiveness to anti-VEGF. Chemically induced colitis (CIC) in cis-ApcΔ716/Smad4+/- and cis-ApcΔ716/Smad4+/-KrasG12D mice promoted development of colon tumors that were largely resistant to anti-VEGF treatment. The myeloid growth factor G-CSF was markedly increased in the serum after induction of colitis. Antibodies blocking G-CSF, or its target Bv8/PROK2, suppressed tumor progression and myeloid cell infiltration when combined with anti-VEGF in CIC-associated CRC and in anti-VEGF-resistant CRC liver metastasis models. In a series of CRC specimens, tumor-infiltrating neutrophils strongly expressed Bv8/PROK2. CRC patients had significantly higher plasma Bv8/PROK2 levels than healthy volunteers and high plasma Bv8/PROK2 levels were inversely correlated with overall survival. Our findings establish Bv8/PROK2 as a translational target in CRC, in combination with anti-VEGF agents.