Prevalence of saliva immunoglobulin A antibodies reactive with severe acute respiratory syndrome coronavirus 2 among Japanese people unexposed to the virus.

While the COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a threat to public health as the number of cases and COVID-19-related deaths are increasing worldwide, the incidence of the virus infection is extremely low in Japan compared with many other countries. To explain this uncommon phenomenon, we investigated the prevalence of naturally occurring ("natural") antibodies, focusing on those of the secretory immunoglobulin A (sIgA) form, reactive with SARS-CoV-2 among Japanese people. One hundred and eighty healthy Japanese volunteers of a wide range of age who had been considered to be unexposed to SARS-CoV-2 participated in this study. Saliva samples and blood samples were collected from all of the 180 participants and 139 adults (aged ≥ 20 years) included therein, respectively. The determination of saliva IgA antibodies, mostly comprising sIgA antibodies, as well as serum IgA and immunoglobulin G antibodies, reactive with the receptor binding domain of the SARS-CoV-2 spike-1 subunit proteins was conducted using an enzyme-linked immunosorbent assay. The major findings were that 52.78% (95% confidence interval, 45.21%-60.25%) of the individuals who had not been exposed to SARS-CoV-2 were positive for saliva IgA antibodies with a wide range of levels between 0.002 and 3.272 ng/mL, and that there may be a negative trend in positivity for the antibodies according to age. As we had expected, a frequent occurrence of assumable "natural" sIgA antibodies reactive with SARS-CoV-2 among the studied Japanese participant population was observed.

Association between selective IgA deficiency and COVID-19.

The purpose of this study was to propose a hypothesis that there is a potential association between the incidence of selective IgA deficiency in various countries and COVID-19 cases. The number of deaths due to COVID-19 increased in clear proportion to the number of infected patients, and the difference in the number of deaths by country was due to the difference in the number of infected patients. The frequency of selective IgA deficiency has a strong positive correlation with the prevalence of COVID-19 per population. The low infection rate contributed to the low death rate from COVID-19 in Japan, suggesting that the extremely low frequency of selective IgA deficiency may be a contributing factor.

Monocyte Chemoattractant Protein-1 (MCP-1) as a Potential Therapeutic Target and a Noninvasive Biomarker of Liver Fibrosis Associated With Transient Myeloproliferative Disorder in Down Syndrome.

Liver fibrosis is one of the common complications of transient myeloproliferative disorder (TMD) in Down syndrome (DS), but the exact molecular pathogenesis is largely unknown. We herein report a neonate of DS with liver fibrosis associated with TMD, in which we performed the serial profibrogenic cytokines analyses. We found the active monocyte chemoattractant protein-1 expression in the affected liver tissue and also found that both serum and urinary monocyte chemoattractant protein-1 concentrations are noninvasive biomarkers of liver fibrosis. We also showed a prospective of the future anticytokine therapy with herbal medicine for the liver fibrosis associated with TMD in DS.

New photic stimulating system with white light-emitting diodes to elicit electroretinograms from zebrafish larvae.

PURPOSE: The zebrafish is an established animal model commonly used in biological, neuroscience, and genetic research. We have developed a new light stimulating system using white light-emitting diodes (LEDs) to elicit ERGs from zebrafish larvae. The purpose of this study was to record full-field ERGs and to evaluate the inter-trial reliability of the ERGs recorded with our system from zebrafish larvae. METHODS: The stimulating device used white LEDs that were attached to a stereomicroscope, and the location of the recording electrode on the cornea could be monitored while the eye was being stimulated. Full-field scotopic and photopic ERGs were recorded from larvae at the age of 5-7 days post-fertilization (dpf). Intensity-response curves were constructed from the ERGs. Inter-trial reliability of the ERGs recorded by our system was evaluated. RESULTS: This stimulating system could be used for efficient and reliable ERG recordings from 5-7 dpf larvae. The amplitudes, implicit times, and the waveforms of the scotopic and photopic ERGs were similar to those reported in earlier studies. Inter-trial reliability of the amplitudes of the photopic ERG b-waves was excellent with an intra-class correlation coefficient of 0.98. CONCLUSION: We conclude that this new light stimulation system using white LEDs attached to a stereomicroscope will be helpful in recording reliable ERGs from zebrafish larvae.

Clinical impact of gastroenterologist-administered propofol during esophagogastroduodenoscopy: a randomized comparison at a single medical clinic.

BACKGROUND: Although midazolam is widely used during endoscopic procedures by endoscopists, propofol has been recently favored for its rapid action and metabolism. The aim of this study is to compare the clinical advantages between propofol and midazolam use during screening esophagogastroduodenoscopy (EGD) for gastric cancer and post-procedure management at a medical clinic. METHODS: One hundred six healthy patients aged 20-69 years requesting sedation for screening EGD from October 2012 to May 2013 at a single clinic in Japan were randomly assigned to propofol (n = 54) or midazolam (n = 52). Medications were given by bolus injection, and the dose was adjusted by body weight. Sedation level and tolerability during EGD and recovery time were assessed. Sedation level and tolerability were evaluated by American Society of Anesthesiologists responsiveness levels and four levels of the gag reflex, respectively. For safety purposes, endoscopists and nurses were trained in administering propofol and an anesthesiologist was on call at all times. RESULTS: No statistically significant differences were found between the two groups in sedation level and patient tolerability. Full recovery time in the propofol group (4.7 min) was significantly shorter than that in the midazolam group (24 min, P < 0.01). CONCLUSIONS: Regarding post-procedure management of patients in a medical clinic, propofol use might not necessitate a recovery room and excessive assessment tasks because of rapid recovery time without any prolonged reaction, which causes patient compliance. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000009142.).

Predicting early intrahepatic recurrence after curative resection of colorectal liver metastases with molecular markers.

BACKGROUND: The aim of this case-control study was to identify clinicopathological factors and test three relevant biomarkers for their ability to predict early intrahepatic recurrence after curative liver resection for colorectal liver metastases (CLM). METHODS: Of the 184 patients with CLM undergoing hepatectomy between January 2007 and December 2009, thirty patients had intrahepatic disease recurrence within 6 months. The control group was randomly selected from a cohort of patients between April 1997 and December 2005 who have survived without disease recurrence after CLM resection for over 5 years. Both groups were matched for size of metastasis greater than 5.0 cm, the presence of multiple metastases, and synchronous versus metachronous CLM. The final study population consisted of 60 patients with CLM undergoing R0 hepatectomy, 30 of whom had early intrahepatic-only recurrences (study group) and 30 patients without recurrence for more than 5 years (control group). Both groups were analyzed and compared for the presence of clinical factors and expression levels of CD133, survivin, and Bcl-2 within tumor tissue. RESULTS: Characteristics of patients were similar between the two groups except primary tumor location and administration of postoperative chemotherapy. Expression level of CD133 and survivin were significantly increased in tumors of patients with recurrence compared to patients without recurrence. On multivariate analysis high tumor expression levels of CD133 (odds ratio [OR] 14.7, confidence interval [CI] 1.8-121.3, p = 0.012) and survivin (OR 9.5, CI 2.1-44.3, p = 0.004) and postoperative chemotherapy (OR 4.8, CI 1.01-22.9, p = 0.049) were independent factors associated with early intrahepatic recurrence. CONCLUSIONS: Tumor expression levels of CD133 and survivin may be a useful predictor of early intrahepatic recurrence after hepatectomy for CLM. Administration of postoperative chemotherapy may prevent early intrahepatic recurrence.

Role of blood ribosomal protein S19 in coagulum resorption: a study using Gln137Glu-ribosomal protein S19 gene knock-in mouse.

Sera of human, guinea pig or mouse contain a strong monocyte chemoattractant capacity that is attributed to the ribosomal protein S19 (RP S19) oligomers generated during blood coagulation. In contrast, sera prepared from Gln137Glu-RP S19 gene knock-in mice contained negligible chemoattractant capacity. When coagula that had been pre-formed from the blood of both the wild type and knock-in mice were intraperitoneally inserted into host mice, after 3 days of recovery, the knock-in mouse coagula remained larger than the wild type mouse coagula. The wild type mouse coagula were covered by multiple macrophage layers at the surface and were infiltrated inside by macrophages. Knock-in mouse coagula exhibited less macrophage involvement. When coagula of knock-in mice and coagula of knock-in mice containing C5a/RP S19, an artificial substitute of the RP S19 oligomers, were intraperitoneally inserted as pairs, the C5a/RP S19 containing coagulum was more rapidly absorbed, concomitant with increased macrophage involvement. Finally, when the knock-in mouse and wild type mouse coagula pairs were inserted into mice in which macrophages had been depleted using clodronate liposome, the size difference of recovered coagula was reversed. These results indicate the importance of the RP S19 oligomer-induced macrophage recruitment in coagulum resorption.

Molecular Events in Immune Responses to Sublingual Influenza Vaccine with Hemagglutinin Antigen and Poly(I:C) Adjuvant in Nonhuman Primates, Cynomolgus Macaques.

Sublingual vaccines offer the benefits of inducing mucosal immunity to protect against respiratory viruses, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and influenza, while also enabling needle-free self-administration. In a previous study, a sublingual SARS-CoV-2 vaccination was created by combining a recombinafigureCoV-2 spike protein receptor-binding domain antigen with a double strand RNA Poly(I:C) adjuvant. This vaccine was tested on nonhuman primates, Cynomolgus macaques. This study examined the immune and inflammatory responses elicited by the sublingual influenza vaccine containing hemagglutinin (HA) antigen and Poly(I:C) adjuvants, and assessed the safety of this vaccine in nonhuman primates. The Poly(I:C)-adjuvanted sublingual vaccine induced both mucosal and systemic immunities. Specifically, the sublingual vaccine produced HA-specific secretory IgA antibodies in saliva and nasal washings, and HA-specific IgA and IgG were detected in the blood. This vaccine appeared to be safe, as judged from the results of blood tests and plasma C-reactive protein levels. Notably, sublingual vaccination neither increased the production of inflammation-associated cytokines-IFN-alpha, IFN-gamma, and IL-17-in the blood, nor upregulated the gene expression of proinflammatory cytokines-IL12A, IL12B, IFNA1, IFNB1, CD69, and granzyme B-in white blood cells. Moreover, DNA microarray analyses revealed that sublingual vaccination evoked both enhancing and suppressing expression changes in genes associated with immune-related responses in cynomolgus monkeys. Therefore, the sublingual vaccine with the Poly(I:C) adjuvant is safe, and creates a balanced state of enhancing and suppressing the immune-related response.

Involvement of cross-linked ribosomal protein S19 oligomers and C5a receptor in definitive erythropoiesis.

We performed a series of experiments under a working hypothesis that cross-linked oligomers of ribosomal protein S19 (RP S19) play an essential role in definitive erythropoiesis as a ligand of the C5a receptor of erythroblasts and macrophages. We found molecules functionally and immunologically indistinguishable from RP S19 oligomers in the extracellular fluid of porcine and guinea pig bone marrow. When an increased hematopoietic state was induced in guinea pigs by bloodletting, the bone marrow RP S19 oligomer concentration was concomitantly increased. However, when the RP S19 oligomers were immunologically neutralized or the C5a receptor was pharmacologically antagonized, hyper-erythropoiesis induced by bloodletting was prevented and the anemic state was retarded in guinea pigs. When the RP S19 oligomers were neutralized in mice after bloodletting, the reactive hyper proliferation of erythroblasts in the spleen was prevented. Proerythroblasts and erythroblasts prepared by bone marrow aspiration from healthy individuals were found to express significant levels of the C5a receptor and type 2 transglutaminase genes. Majority of erythroblasts in cord blood of healthy newborns bore the C5a receptor. Taken together, these results support our hypothesis.

Involvement of regional neutrophil apoptosis promotion by ribosomal protein S19 oligomers in resolution of experimental acute inflammation.

Isolated peripheral neutrophils spontaneously underwent apoptosis in association with extra-cellular liberation of the monocyte-attracting ribosomal protein S19 (RP S19) oligomers. This apoptosis was prevented by the simultaneous presence of anti-RP S19 antibodies or of a C5a receptor antagonist, but was promoted by supplementing extrinsic RP S19 oligomers. Transformed HL-60 cells to over-produce Gln137Asn-mutant RP S19 were differentiated to neutrophil-like cells. The neutrophil-like cells gained resistance against the spontaneous apoptosis concomitant with the generation of non-functional RP S19 oligomers. When the neutrophil-like cells were intradermally transplanted into mice, the mutant RP S19-producing neutrophils persisted for a long period of time, whereas wild-type RP S19-producing neutrophils underwent apoptosis and were promptly cleared by infiltrated macrophages. When an experimental pleurisy was introduced by injecting carrageenan into the pleural cavity of mice, the inflammation spread slightly to lung parenchyma. When antibodies neutralizing the RP S19 oligomers were simultaneously administrated with carrageenan, the neutrophil infiltration in the lung parenchymal lesion become more severe, occurring as alveolar septal destruction and hemorrhage concomitant with an augmented neutrophil number in the pleural exudate. These results indicate the importance of the RP S19 oligomers and the C5a receptor in neutrophil clearance and acute inflammation resolution.

SARS-CoV-2 sublingual vaccine with RBD antigen and poly(I:C) adjuvant: Preclinical study in cynomolgus macaques.

Mucosal vaccine for sublingual route was prepared with recombinant SARS-CoV-2 spike protein receptor binding domain (RBD) antigen and poly(I:C) adjuvant components. The efficacy of this sublingual vaccine was examined using Cynomolgus macaques. Nine of the macaque monkeys were divided into three groups of three animals: control [just 400 µg poly(I:C) per head], low dose [30 µg RBD and 400 µg poly(I:C) per head], and high dose [150 µg RBD and 400 µg poly(I:C) per head], respectively. N-acetylcysteine (NAC), a mild reducing agent losing mucin barrier, was used to enhance vaccine delivery to mucosal immune cells. RBD-specific IgA antibody secreted in pituita was detected in two of three monkeys of the high dose group and one of three animals of the low dose group. RBD-specific IgG and/or IgA antibodies in plasma were also detected in these monkeys. These indicated that the sublingual vaccine stimulated mucosal immune response to produce antigen-specific secretory IgA antibodies in pituita and/or saliva. This sublingual vaccine also affected systemic immune response to produce IgG (IgA) in plasma. Little RBD-specific IgE was detected in plasma, suggesting no allergic antigenicity of this sublingual vaccine. Thus, SARS-CoV-2 sublingual vaccine consisting of poly(I:C) adjuvant showed reasonable efficacy in a non-human primate model.

Dual functions of the C5a receptor as a connector for the K562 erythroblast-like cell-THP-1 macrophage-like cell island and as a sensor for the differentiation of the K562 erythroblast-like cell during haemin-induced erythropoiesis.

The transcriptional nuclear factor binding to the Y box of human leukocyte antigen genes (NF-Y) for the C5a receptor (C5aR) gene is active in erythroblasts. However, the roles of the C5aR in erythropoiesis are unclear. We have previously demonstrated that apoptotic cell-derived ribosomal protein S19 (RP S19) oligomers exhibit extraribosomal functions in promoting monocyte chemotaxis and proapoptosis via the C5aR without receptor internalisation. In contrast to the extraribosomal functions of the RP S19, a proapoptotic signal in pro-EBs, which is caused by mutations in the RP S19 gene, is associated with the inherited erythroblastopenia, Diamond-Blackfan anaemia. In this study, we detected C5aR expression and RP S19 oligomer generation in human erythroleukemia K562 cells during haemin-induced erythropoiesis. Under monocell culture conditions, the differentiation into K562 erythrocyte-like cells was enhanced following the overexpression of Wild-type RP S19. Conversely, the differentiation was repressed following the overexpression of mutant RP S19. An RP S19 oligomer inhibitor and a C5aR inhibitor blocked the association of the K562 basophilic EB-like cells and the THP-1 macrophage-like cells under coculture conditions. When bound to RP S19 oligomers, the C5aR may exhibit dual functions as a connector for the EB-macrophage island and as a sensor for EB differentiation in the bone marrow.

Guideline for hereditary angioedema (HAE) 2010 by the Japanese Association for Complement Research - secondary publication.

This guideline was provided by the Japanese Association for Complement Research targeting clinicians for making an accurate diagnosis of hereditary angioedema (HAE), and for prompt treatment of the HAE patient in Japan. This is a 2010 year version and will be updated according to any pertinent medical advancements.

Epstein-Barr virus-related diffuse large B-cell lymphoma type methotrexate-associated lymphoproliferative disorders presenting in the adrenal gland.

Introduction: Methotrexate-associated lymphoproliferative disorders appear during treatment with methotrexate as an immunosuppressive drug. However, the mechanism and frequency are still unknown, and the treatment is undefined. Case presentation: A 76-year-old woman was admitted to the hospital with back pain, and magnetic resonance imaging showed a tumor in the right adrenal region. She had received methotrexate for rheumatoid arthritis. Enhanced computed tomography showed a tumor of 90 mm in diameter on the dorsal side of the liver abutting to the inferior vena cava. The preoperative diagnosis was a hepatic invasion of right adrenocortical carcinoma and right adrenalectomy was performed. The histopathological diagnosis was diffuse large B-cell lymphoma. The final diagnosis was methotrexate-associated lymphoproliferative disorders. Conclusion: It is important to consider methotrexate-associated lymphoproliferative disorders before surgery when neoplastic lesions are found in patients taking methotrexate.

Incidental Sacral Meningocele in an Elderly Patient Diagnosed After Epidermal Inclusion Cyst Removal: A Case Report.

A meningocele is a congenital neural tube defect, and the majority of the meningocele cases are identified perinatally. We present the case of a 67-year-old patient with a sacral meningocele undiagnosed until the removal of a symptomatic epidermal inclusion cyst adjacent to it. Cerebrospinal fluid leakage occurred due to an incision in an undiagnosed meningocele adjacent to the epidermal inclusion cyst. Repair of the cerebrospinal fluid leakage was performed successfully without any deficit. The present case underscores the importance of considering a meningocele as a differential diagnosis for a mass occurring in the midline of the back at any age.

A plasma protein indistinguishable from ribosomal protein S19: conversion to a monocyte chemotactic factor by a factor XIIIa-catalyzed reaction on activated platelet membrane phosphatidylserine in association with blood coagulation.

A monocyte-chemoattracting factor is generated during blood coagulation and during clotting of platelet-rich plasma. This chemotactic factor attracts monocytes as a ligand of the C5a receptor; however, it inhibits C5a-induced neutrophil chemotaxis as an apparent receptor antagonist. The curious dual function of the serum monocyte chemotactic factor resembles that of the cross-linked homodimer of ribosomal protein S19 (RP S19). Indeed, the inactive precursor of the monocyte chemotactic factor was present in plasma, and the precursor molecule and RP S19, as well as the active form and the RP S19 dimer, were indistinguishable in terms of immunological reactivity and molecular size. Coagulation factor XIIIa, plasma transglutaminase, and membrane phosphatidylserine on the activated platelets were required for conversion of the precursor to the active form. In addition, the precursor molecule in plasma could be replaced by wild-type recombinant RP S19 but not by mutant forms of it. These results indicate that a molecule indistinguishable from RP S19 was present in plasma, and that the RP S19-like molecule was converted to the active form by a transglutaminase-catalyzed reaction on a scaffold that included the phosphatidylserine-exposed platelet membrane.

Maintenance of ribosomal protein S19 in plasma by complex formation with prothrombin.

We have demonstrated that the cross-linking of ribosomal protein S19 (RP S19) on platelets by activated factor XIII provides chemotactic potency to monocytes/macrophages for a resolution of coagulum. Factor XIII is activated by an active form of prothrombin, thrombin. We here report that RP S19 is present as a complex with prothrombin in the blood stream. Formation of this complex was blocked by a mutation of the glycosaminoglycan-binding basic cluster (Lys(23) -Lys(29) ) in RP S19. Prothrombin-RP S19 interaction was enhanced by an absence of Ca(2+) and the plasma RP S19 concentration was significantly low in the patient treated with warfarin, indicating participation of the γ-carboxyl glutamic acid domain of prothrombin making a salt bridge with the basic cluster. The complex formation likely explains why a protein as small as RP S19 can prevent from a filtering system of renal glomeruli at a steady state. The translocation of RP S19 from prothrombin to platelets during blood coagulation seems to be also advantageous for RP S19 from the perspective of oligomerisation by activated factor XIII, which should have been activated by thrombin.

Role of ribosomal protein S19-like plasma protein in blood coagulum resorption.

Western blot analyses and monocyte chemoattraction analyses of guinea pig plasma and serum indicated the presence of a plasma protein indistinguishable from ribosomal protein S19 and the cross-linked dimerization of it gaining monocyte chemotactic capacity in association with blood coagulation as in the case of human. When coagula preformed in vitro were intraperitoneally inserted into guinea pigs, they were rapidly covered by macrophages within 24h concomitant with an intra-coagulum macrophage infiltration. Differences were observed between the surface macrophages and the penetrating macrophages in ultrastructural, histochemical and immunohistochemical analyses. The inserted coagula were resorbed by day 7. When either anti-RP S19 antibodies or Gln137Asn-RP S19, a competitive inhibitor against RP S19, was premixed into the inserted coagulum, the attachment and penetration by macrophages decreased and the coagulum resorption retarded. These results indicate the role of the plasma RP S19-like molecule in coagulum resorption via macrophage recruitment.

Glyceraldehyde-derived advanced glycation end-products having pyrrolopyridinium-based crosslinks.

Reducing sugars and reactive aldehydes, such as glyceraldehyde, non-enzymatically react with amino or guanidino groups of proteins to form advanced glycation end-products (AGEs) by the Maillard reaction that involves Schiff base formation followed by Amadori rearrangement. AGEs are found relatively in abundance in the human eye and to accumulate at a higher rate in diseases that impair vision such as cataract, diabetic retinopathy or age-related macular degeneration. We identified two novel AGEs of pyrrolopyridinium lysine dimer derived from glyceraldehyde, PPG1 and PPG2, in the Maillard reaction of N α-acetyl-l-lysine with glyceraldehyde under physiological conditions. Having fluorophores similar to that of vesperlysine A, which was isolated from the human lens, PPGs were found to act as photosensitizers producing singlet oxygen in response to blue light irradiation. Moreover, PPG2 interacts with receptor for AGE (RAGE) in vitro with a higher binding affinity than GLAP, a well-known ligand of the receptor. We also proposed a pathway to form PPGs and discussed how they would be formed in vitro. As glyceraldehyde-derived AGEs have been studied extensively in connection with various hyperglycemia-related diseases, further studies will be required to find PPGs in vivo such as in the lens or other tissues.

The role of the ribosomal protein S19 C-terminus in Gi protein-dependent alternative activation of p38 MAP kinase via the C5a receptor in HMC-1 cells.

We have demonstrated that an alternative C5a receptor (C5aR) ligand, the homodimer of ribosomal protein S19 (RP S19), contains a unique C-terminus (I(134)-H(145)) that is distinct from the moieties involved in the C5a-C5aR interaction. To examine the role of I(134)-H(145) in the ligand-C5aR interaction, we connected this peptide to the C-terminus of C5a (C5a/RP S19) and found that it endowed the second binding moiety of RP S19 (L(131)DR) with a relatively higher binding affinity to the C5aR on a human mast cell line, HMC-1. In contrast to the C5aR, the second C5aR C5L2 worked as a decoy receptor. As a result, the mitogen-activated protein kinase (MAPK) downstream of the Gi protein exchanged extracellular-signal regulated kinase for p38MAPK. This alternative p38MAPK activation could be pharmacologically suppressed not only by the downregulation of phosphoinositide 3-kinase (PI3K) by LY294002, but also by the over-activation of protein kinase C by phorbol 12-myristate 13-acetate. The activation was reproduced upon C5a-C5aR interaction by a simultaneous suppression of PI3K and phospholipase C with LY294002 and U73122 at low concentrations. Moreover, p38MAPK phosphorylation upstream of the pertussis toxin-dependent extracellular Ca(2+) entry was also suppressed by high concentrations of MgCl(2), which blocks melastatin-type transient receptor potential Ca(2+) channels (TRPMs). The active conformation of C5aR upon the ligation by C5a, at least on HMC-1 cells, is changed by the additional interaction of the I(134)-H(145) peptide, which seems to guide the alternative activation of p38MAPK. This activation is then amplified by a novel positive feedback loop between p38MAPK and TRPM.