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Abstract Background Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) is a disease entity with nonorganized granular glomerular deposition with monoclonal proteins of both heavy and light chains. Dysproteinemia was observed in only 30% of the patients with PGNMID. We herein report a case of PGNMID with discrepancy between serum and glomerular deposits. Case presentation The patient was a 50-year-old man who had been followed at a local clinic due to hypertension, type 2 diabetes, hyperlipidemia, hyperuricemia, fatty liver, and obesity. Proteinuria had been noted five years previously, and he had been referred to a hematology department due to hyperproteinemia, high gamma globulin, and κ Bence-Jones protein (BJP) positivity one year previously. Bone marrow aspiration showed 5% plasma cells, and he was referred to the nephrology department to evaluate persistent proteinuria. He was hypertensive, and his estimated glomerular filtration rate was 54.2 ml/min/1.73 m2. His urinary protein level was 0.84 g/g⋅Cr. Urine and serum immunofixation showed BJP-κ type and IgG-κ type, respectively. Kidney biopsy showed an increase in mesangial cells and matrix without nodular lesions under a light microscope. Immunofluorescence microscopy showed granular deposits of IgG and C3 on the capillary wall and weak positivity for C1q. IgG3 was predominant among the IgG subclasses, and intraglomerular κ and λ staining was negative for κ and positive for λ. Direct fast scarlet staining was negative. Electron microscopy showed lumpy deposits without a fibrillar structure in the subepithelial area. Based on the above findings, a diagnosis of membranous nephropathy-type PGNMID was made. Since proteinuria increased gradually after three years of treatment with valsartan (40 mg, daily), oral prednisolone (30 mg, daily) was initiated, which led to decreased proteinuria. The dose of oral prednisolone was gradually tapered to 10 mg per day. At that time, proteinuria was 0.88 g/g⋅Cr. We found 204 cases in 81 articles in the PubMed database, among which 8 showed discrepancy in the heavy and/or light chains between serum and kidney. Conclusions We experienced a case of membranous nephropathy-type PGNMID with discrepancy in light chains between serum and kidney that was successfully treated with oral prednisolone.

Background/Objectives: FVIII reagent activity varies across different assays, as well as activated partial thromboplastin time (APTT) reagents. The hemostatic ability of various FVIII reagents was examined via clot waveform analysis (CWA). Methods: APTT was measured using 12 APTT reagents, a small amount of tissue factor-induced FIX activation (sTF/FIXa) and a small amount of thrombin time (sTT) in order to examine 10 FVIII reagents and reference plasma (RP) using CWA. FVIII activity was measured using CWA-APTT, a chromogenic assay, or CWA-sTT. Results: Although the peak time (PT) and peak height (PH) of the CWA-APTT were markedly different in different FVIII reagents using several APTT reagents, the PTs of CWA-APTT were generally normal or shortened and the PHs of CWA-APTT were generally lower than those of RP. The FVIII activity varied, as evaluated using APTT, and was higher when using the CWA-sTT method than the APTT or chromogenic methods. CWA-sTT showed an elevated second peak of first DPH in all FVIII reagents, and both CWA-sTF/FIXa and CWA-sTT were enhanced using APTT reagents. Conclusions: Our evaluation of the hemostatic ability of FVIII reagents varied among APTT reagents. CWA-sTT can be used to further evaluate the hemostatic ability of an FVIII concentrate based on thrombin burst.

Summary: Adoptive cell therapy using allogeneic γδ-T cells is a promising option for off-the-shelf T cell products with a low risk of graft-versus-host disease (GVHD). Long-term persistence may boost the clinical development of γδ-T cell products. In this study, we found that genetically modified Vγ9+Vδ2+ T cells expressing a tumor antigen-specific αβ-TCR and CD8 coreceptor (GMC) showed target-specific killing and excellent persistence. To determine the mechanisms underlying these promising effects, we investigated metabolic characteristics. Cytokine secretion by γδ-TCR-stimulated nongene-modified γδ-T cells (NGMCs) and αβ-TCR-stimulated GMCs was equally suppressed by a glycolysis inhibitor, although the cytokine secretion of αβ-TCR-stimulated GMCs was more strongly inhibited by ATP synthase inhibitors than that of γδ-TCR-stimulated NGMCs. Metabolomic and transcriptomic analyses, flow cytometry analysis using mitochondria-labeling dyes and extracellular flux analysis consistently suggest that αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function.In conclusion, αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function with promising persistence.

Abstract Tacrolimus interacts with letermovir and azole antifungals, whereas letermovir has nonuniform effects on the pharmacokinetics of azole antifungals. We retrospectively investigated the interaction of tacrolimus (continuous infusion) with letermovir considering co‐administered azole antifungals in adult hematopoietic stem cell transplantation patients. The extent of intraindividual variation in the ratio of tacrolimus concentration to dose normalized by body weight (C/D ratio) was investigated. The correlation between the C/D ratio and estimated glomerular filtration rate (eGFR) was analyzed. In 35 patients (795 points), the C/D ratio was higher in the tacrolimus plus letermovir period than in the tacrolimus alone period (1234.7 [566.2–2721.0] ng/mL/mg/kg vs. 564.4 [245.3–1861.3] ng/mL/mg/kg, p

Abstract Radiation‐induced lung damage (RILD) is a critical problem in lung cancer radiotherapy, and it is difficult to predict its severity. Although no biomarkers for RILD have been established, tenascin C (TNC) is an extracellular matrix glycoprotein involved in the remodeling of damaged tissues and has been implicated in inflammation and fibrosis. We report the unique case of a 36‐year‐old man with adenocarcinoma of the lung, Union for International Cancer Control stage IIIB, who was treated with radiotherapy before lung surgery. The surgical specimen showed histopathological expression of TNC in the region where radiation pneumonitis was observed radiographically. Serum TNC levels were elevated after radiotherapy. In this case, TNC is suggested to be implicated in RILD and may be a potential candidate as a biomarker for the onset and severity of the condition.

The licensing process mediated by inhibitory receptors of the Ly49 C-type lectin superfamily that recognizes self-major histocompatibility complex (MHC) class I in mice is essential for the proper antitumor function of natural killer (NK) cells. Several models for NK cell licensing can be exploited for adoptive immunotherapy for cancer. However, the appropriate adoptive transfer setting to induce efficient graft versus tumor/leukemia effects remains elusive, especially after hematopoietic stem cell transplantation (HSCT). In our previous experiment, we showed that intraperitoneal neutrophil administration with their corresponding NK receptor ligand-activated NK cells using congenic mice without HSCT. In this experiment, we demonstrate enhanced antitumor effects of licensed NK cells induced by weekly intraperitoneal injections of irradiated neutrophil-enriched peripheral blood mononuclear cells (PBMNCs) in recipient mice bearing lymphoma. Bone marrow transplantation was performed using BALB/c mice (H-2d) as the recipient and B10 mice (H-2b) as the donor. The tumor was A20, a BALB/c-derived lymphoma cell line, which was injected subcutaneously into the recipient at the same time as the HSCT. Acute graft versus host disease was not exacerbated in this murine MHC class I mismatched HSCT setting. The intraperitoneal injection of PBMNCs activated a transient licensing of NK subsets expressed Ly49G2, its corresponding NK receptor ligand to H-2d, and reduced A20 tumor growth in the recipient after HSCT. Pathological examination revealed that increased donor-oriented NK1.1+NK cells migrated into the recipient tumors, depending on neutrophil counts in the administered PBMNCs. Collectively, our data reveal a pivotal role of neutrophils in promoting NK cell effector functions and adoptive immunotherapy for cancer.

Undifferentiated neoplasms of unknown primary sites are rare. It is difficult to identify their characteristics and determine the appropriate chemotherapy regimen to be used. Undifferentiated/rhabdoid carcinoma is reportedly associated with loss of SWI/SNF chromatin remodeling complexes, such as observed in SMARCA4-deficient tumors. However, little is known about SMARCA2/BRM-deficient tumors. A 48-year-old man presented with low back pain. Computed tomography (CT) revealed intraperitoneal lymph nodes and multiple bone metastases that invaded the thoracic and lumbar spinal canals. The primary tumor was not identified despite the standard diagnostic methods being used. CT-guided needle biopsy of right iliac bone metastasis showed that the tumor had an undifferentiated/rhabdoid morphology. Immunostaining revealed that the tumor was SMARCA2/BRM-deficient despite both SMARCB1/INI1 and SMARCA4/BRG being retained. We found no genomic alterations during domestic next-generation sequencing panel profiling, which can identify 114 genes. Thus, he was diagnosed with SMARCA2/BRM-deficient undifferentiated/rhabdoid carcinoma of an unknown primary site with multiple bone metastases and intraperitoneal lymph node metastasis. We administered radiotherapy to the thoracic and lumbar spine to improve cord compression, and carboplatin (CBDCA) and paclitaxel regimen was chosen as first-line chemotherapy, but this was discontinued due to an anaphylactic shock. We then selected the CBDCA and gemcitabine regimens; however, the patient did not continuously receive the regimen due to myelosuppression. Radiation therapy effectively relieves pain and cord compression. To our knowledge, this is the first reported case of SMARCA2/BRM-deficient undifferentiated/rhabdoid carcinoma of an unknown primary site. Further studies are needed to improve SWI/SNF-deficient tumor identification methods.

Background: Regular prophylactic therapy has become an increasingly common treatment for severe hemophilia. Therefore, hypercoagulability—a potential risk factor of thrombosis—is a cause for concern in hemophilic patients treated with a high dose of FVIII concentrate. In clot waveform analysis (CWA)-thrombin time (TT), a small amount of thrombin activates clotting factor VIII (FVIII) instead of fibrinogen, resulting in FVIII measurements using CWA-TT with a small amount of thrombin. Methods: The coagulation ability of patients treated with FVIII concentrate or emicizumab was evaluated using activated partial thromboplastin time (APTT), TT and a small amount of tissue factor-induced FIX activation assay (sTF/FIXa) using CWA. Results: The FVIII activity based on CWA-TT was significantly greater than that based on the CWA-APTT or chromogenic assay. FVIII or FVIII-like activities based on the three assays in plasma without emicizumab were closely correlated; those in plasma with emicizumab based on CWA-TT and chromogenic assays were also closely correlated. CWA-APTT and CWA-TT showed different patterns in patients treated with FVIII concentrates compared to those treated with emicizumab. In particular, CWA-TT in patients treated with FVIII concentrate showed markedly higher peaks in platelet-rich plasma than in platelet-poor plasma. CWA-APTT showed lower coagulability in hemophilic patients treated with FVIII concentrate than in healthy volunteers, whereas CWA-sTF/FIXa did not. In contrast, CWA-TT showed hypercoagulability in hemophilic patients treated with FVIII concentrate. Conclusions: CWA-TT can be used to evaluate the thrombin bursts that cause hypercoagulability in patients treated with emicizumab. Although routine APTT evaluations demonstrated low coagulation ability in patients treated with FVIII concentrate, CWA-TT showed hypercoagulability in these patients, suggesting that the evaluation of coagulation ability may be useful when using multiple assays.

Abstract Introduction Graft‐versus‐host disease (GVHD) is frequent and fatal complication following allogeneic hematopoietic stem cell transplantation (HSCT) and characteristically involves skin, gut, and liver. Macrophages promote tissue regeneration and mediate immunomodulation. Macrophages are divided into two different phenotypes, classically activated M1 (pro‐inflammatory or immune‐reactive macrophages) and alternatively activated M2 (anti‐inflammatory or immune‐suppressive macrophages). The anti‐inflammatory effect of M2 macrophage led us to test its effect in the pathophysiology of GVHD. Methods GVHD was induced in lethally irradiated BALB/c mice. M2 macrophages derived from donor bone marrow (BM) were administered intravenously, while controls received donor BM‐mononuclear cells and splenocytes. Animals were monitored for clinical GVHD and analyzed. Results We confirmed that administering donor BM‐derived M2 macrophages attenuated GVHD severity and prolonged survival after HSCT. Moreover, donor BM‐derived M2 macrophages significantly suppressed donor T cell proliferation by cell‐to‐cell contact in vitro. Conclusions We showed the protective effects of donor‐derived M2 macrophages on GVHD and improved survival in a model of HSCT. Our data suggest that donor‐derived M2 macrophages offer the potential for cell‐based therapy to treat GVHD.

Abstract The introduction of anti-inflammatory therapies has enabled substantial improvement of disease activity in patients with inflammatory bowel diseases (IBD). However, IBD can lead to serious complications such as intestinal fibrosis and colorectal cancer. Therefore, novel therapies reducing the development of these complications are needed. Angiotensin II (Ang II) promotes tissue inflammation by stimulating the production of monocyte chemoattractant protein-1 (MCP-1) or proinflammatory cytokines. It plays a pivotal role in IBD progression. Although blockade of Ang II has been reported to ameliorate experimental colitis and reduce colorectal cancer risk, the cellular and molecular mechanisms remain poorly understood. Our previous work showed that irbesartan, an Ang II type 1 receptor blocker, reduced the number of C–C chemokine receptor 2-positive (CCR2+) monocytic cells in the inflamed pancreas. This study aimed to investigate the possible antifibrotic and antitumour effects of irbesartan using the azoxymethane/dextran sodium sulphate mouse model. Irbesartan suppressed MCP-1 production and the accumulation of Ly6C+CCR2+ monocytes and fibrocytes in the inflamed colon, downregulated the expression of type 1 collagen and matrix metalloproteinase 9 and inhibited the development of intestinal fibrosis and tumours. Our observations suggest that blocking the MCP-1/CCR2 pathway using irbesartan might be beneficial in preventing colitis-associated colon tumours.

Tumor-related sarcoidosis-like reactions (SLR) have been reported with the use of immune checkpoint inhibitors (ICIs). We report a case of 50-year-old woman who observed an enlarged lymph node in the right hilar region and the appearance of a subcutaneous mass in the extremities during chemotherapy with atezolizumab plus nab-paclitaxel for metastatic triple-negative breast cancer (TNBC). Skin biopsy revealed the formation of epithelioid granulation species with the Langhans giant cell. After discontinuing atezolizumab in the treatment procedure, the hilar lymph nodes and the subcutaneous mass were reduced. A pathological examination was effective in differentiating tumor exacerbation from SLR. Owing to limited information on ICI-related SLR in breast cancer, future studies are recommended to properly manage immune-related adverse effects during cancer treatment.

Histoplasmosis, a fungal infection caused by Histoplasma capsulatum, is poor prognosis once it disseminated, especially in immunocompromised patients. A 50-year-old Japanese-Brazilian male with multiple cervical lymphadenopathies was diagnosed as disseminated histoplasmosis and acquired immunodeficiency syndrome (AIDS). Anti-fungal therapy was initiated followed by anti-retroviral therapy (ART). He achieved long-term remission by treatment with voriconazole. Here we report a case of an AIDS patient with disseminated histoplasmosis who achieved long-term survival in non-endemic area. Keywords: Disseminated histoplasmosis, Histoplasma capsulatum, HIV/AIDS

Objective: Although emicizumab is a bispecific, monoclonal antibody that has led to a significant improvement of treatment for hemophilia A patients with inhibitors, the routine monitoring of patients treated with emicizumab is difficult. Thrombin time (TT) reflects thrombin burst, which mainly depends on activation of factor V (FV) and FVIII. Methods: We, therefore, developed a method for evaluating clotting activity independent of the presence of emicizumab. Normal plasma (NP) or FVIII-deficient plasma (FVIIIDP) with and without emicizumab was measured using clot waveform analysis (CWA)-activated partial thromboplastin time (APTT) and TT. Results: Emicizumab caused clot formation in FVIIIDP using the CWA-APTT; however, the coagulation peaks of plasma with and without emicizumab measured by the CWA-TT did not differ to a statistically significant extent. Regarding the mixing tests with NP and FVIIIDP, CWA-APTT showed large differences between each mixing test in plasma with and without emicizumab, whereas the CWA-TT showed similar patterns in mixing plasma with and without emicizumab. Regarding the standard curve of FVIII activity, the CWA-APTT showed an FVIII-concentration-dependent increase; however, the values with each concentration of FVIII differed between samples with and without emicizumab, whereas CWA-TT showed FVIII-concentration-dependent fluctuations independent of the presence of emicizumab, and the values with each concentration of FVIII were similar in samples with and without emicizumab. Conclusions: As CWA-TT using a small amount of thrombin (0.5 IU/mL) can reflect thrombin burst and be useful for evaluating FVIII activity, independent of the presence of emicizumab, it is useful for monitoring clotting activity in patients with an anti-FVIII inhibitor treated with emicizumab.

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death worldwide. The accuracy of a PDAC diagnosis based on endoscopic ultrasonography-guided fine-needle aspiration cytology can be strengthened by performing a rapid on-site evaluation (ROSE). However, ROSE can only be performed in a limited number of facilities, due to a relative lack of available resources or cytologists with sufficient training. Therefore, we developed the Mathematical Technology for Cytopathology (MTC) algorithm, which does not require teaching data or large-scale computing. We applied the MTC algorithm to support the cytological diagnosis of pancreatic cancer tissues, by converting medical images into structured data, which rendered them suitable for artificial intelligence (AI) analysis. Using this approach, we successfully clarified ambiguous cell boundaries by solving a reaction–diffusion system and quantitating the cell nucleus status. A diffusion coefficient (D) of 150 showed the highest accuracy (i.e., 74%), based on a univariate analysis. A multivariate analysis was performed using 120 combinations of evaluation indices, and the highest accuracies for each D value studied (50, 100, and 150) were all ≥70%. Thus, our findings indicate that MTC can help distinguish between adenocarcinoma and benign pancreatic tissues, and imply its potential for facilitating rapid progress in clinical diagnostic applications.

Antifungal prophylaxis is crucial for successful hematopoietic stem cell transplantation (HSCT). Maintenance therapy with fluconazole (FLCZ) is generally prescribed as secondary prophylaxis in patients with human immunodeficiency virus infection and non-immunocompromised hosts. However, previous reports have revealed that FLCZ is insufficient as a secondary prophylaxis for cryptococcal infection in HSCT cases. There is no well-established evidence of effective secondary prophylaxis against cryptococcal infection in conditions of severe immunosuppression, such as in HSCT. Herein, we report a case of atypical chronic myeloid leukemia (aCML) presenting with cryptococcal meningitis. A 58-year-old man with progressive leukocytosis and headache was referred to our hospital. Bone marrow biopsy revealed aCML. Because the estimated overall survival was limited, HSCT was indicated. Furthermore, enhanced magnetic resonance imaging and lumbar puncture aided in diagnosing cryptococcal meningitis, which was treated with a combination therapy comprising liposomal amphotericin B and 5-fluorocystine for 28 days. Given the high recurrence rate of cryptococcal meningitis, voriconazole (VRCZ) dose was calculated using the trough concentration of VRCZ in the cerebrospinal fluid. Eventually, HSCT was successfully performed at an appropriate therapeutic range of VRCZ. To the best of our knowledge, there is no case report on HSCT with secondary prophylaxis against cryptococcal meningitis. Our report thus emphasizes the efficacy of VRCZ maintenance therapy as secondary prophylaxis for cryptococcal infection.

Background: Although platelets, which contain large amounts of phospholipids, play an important role in blood coagulation, there is still no routine assay to examine the effects of platelets in blood coagulation. Methods: Hemostatic abnormalities in patients with thrombocytopenia, including those with idiopathic thrombocytopenic purpura (ITP), were examined using clot wave analysis (CWA)–small-amount tissue-factor-induced FIX activation (sTF/FIXa) and thrombin time (TT). Results: Although there were no marked differences in the three parameters of activated partial thromboplastin time (APTT) between normal healthy volunteers and typical patients with ITP, the peak heights of the CWA-sTF/FIXa were markedly low in patients with ITP. The three peak times of the CWA-sTF/FIXa in patients with a platelet count of ≤8.0 × 1010/L were significantly longer than those in patients with a platelet count > 8.0 × 1010/L and the peak heights of the CWA-sTF/FIXa in patients with a platelet count of ≤8.0 × 1010/L were significantly lower than those in patients with >8.0 × 1010/L. The peak heights of the CWA-APTT in patients with ITP were significantly lower than in patients with other types of thrombocytopenia. The three peak heights of the CWA-sTF/FIXa in ITP patients were significantly lower than those in patients with other types of thrombocytopenia. The CWA-TT showed lower peak heights and longer peak times in patients with ITP in comparison to patients with other types of thrombocytopenia. Conclusions: The CWA-sTF/FIXa and CWA-TT results showed that blood coagulation is enhanced by platelets and that the blood coagulation ability in ITP patients was low in comparison to healthy volunteers and patients with other types of thrombocytopenia.

CD25 is expressed on leukemic cells in 10-20% cases of acute myeloid leukemia (AML), and its expression is associated with poor prognosis. We reevaluated the relationship between CD25 expression and the leukemia-initiating cell (LIC) properties of AML using a patient-derived xenograft model. We divided lineage marker-negative (Lin-) CD34+CD38- or Lin-CD34+ cells from CD25-positive AML into CD25-positive and -negative populations, and then transplanted each population into NOD.Cg-PrkdcscidIl2rgtm1Wjl/Sz mice. Leukemic engraftment was observed with both CD25-positive and -negative populations from three of nine CD25-positive AML patients. In two of those three patients, CD25-positive and -negative Lin-CD34+ cells engrafted at the primary transplantation led to leukemic engraftment at the secondary transplantation, in which engrafted cells contained both CD25-positive and -negative Lin-CD34+ AML cells. In an in vitro culture system, expression of CD25 was considerably induced in the CD25-negative population of Lin-CD34+ cells from two cases of CD25-positive AML. In one case, CD25-positive Lin-CD34+ cells gave rise to CD25-negative as well as -positive CD34+ cells. These observations suggest that there exist CD25-positive and -negative populations that can reconstitute CD25-positive AML in a patient-derived xenograft model, and that CD25 expression fluctuates in the LICs of AML.

Brain natriuretic peptide (BNP) is an important biomarker for patients with cardiovascular diseases, including heart failure, hypertension and cardiac hypertrophy. It is also known that BNP levels are relatively higher in patients with chronic kidney disease and no heart disease; however, the mechanism remains unclear.We developed a BNP reporter mouse and occasionally found that this promoter was activated specifically in the papillary tip of the kidneys, and its activation was not accompanied by BNP mRNA expression. No evidence was found to support the existence of BNP isoforms or other nucleotide expression apart from BNP and tdTomato. The pBNP-tdTomato-positive cells were interstitial cells and were not proliferative. Unexpectedly, both the expression and secretion of BNP increased in primary cultured neonatal cardiomyocytes after their treatment with an extract of the renal papillary tip. Intraperitoneal injection of the extract of the papillary tips reduced blood pressure from 210 mmHg to 165 mmHg, the decrease being accompanied by an increase in serum BNP and urinary cGMP production in stroke-prone spontaneously hypertensive (SHR-SP) rats. Furthermore the induction of BNP by the papillary extract from rats with heart failure due to myocardial infarction was increased in cardiomyocytes.These results suggested that the papillary tip express a substance that can stimulate BNP production and secretion from cardiomyocytes.

Recent studies have shown that monocytes possess pluripotent plasticity. We previously reported that monocytes could differentiate into hepatic stellate cells. Although stellate cells are also present in the pancreas, their origin remains unclear. An accumulation of enhanced green fluorescent protein (EGFP)(+)CD45(-) cells was observed in the pancreases and livers of chimeric mice, which were transplanted with a single hematopoietic stem cell isolated from EGFP-transgenic mice and treated with carbon tetrachloride (CCl4). Because the vast majority of EGFP(+)CD45(-) cells in the pancreas expressed stellate cell-associated antigens such as vimentin, desmin, glial fibrillary acidic protein, procollagen-I, and α-smooth muscle actin, they were characterized as pancreatic stellate cells (PaSCs). EGFP(+) PaSCs were also observed in CCl4-treated mice adoptively transferred with monocytes but not with other cell lineages isolated from EGFP-transgenic mice. The expression of monocyte chemoattractant protein-1 (MCP-1) and angiotensin II (Ang II) increased in the pancreas of CCl4-treated mice and their respective receptors, C-C chemokine receptor 2 (CCR2) and Ang II type 1 receptor (AT1R), were expressed on Ly6C(high) monocytes isolated from EGFP-transgenic mice. We examined the effect of an AT1R antagonist, irbesartan, which is also a CCR2 antagonist, on the migration of monocytes into the pancreas. Monocytes migrated toward MCP-1 but not Ang II in vitro. Irbesartan inhibited not only their in vitro chemotaxis but also in vivo migration of adoptively transferred monocytes from peripheral blood into the pancreas. Irbesartan treatment significantly reduced the numbers of EGFP(+)F4/80(+)CCR2(+) monocytic cells and EGFP(+) PaSCs in the pancreas of CCl4-treated chimeric mice receiving EGFP(+) bone marrow cells. A specific CCR2 antagonist RS504393 inhibited the occurrence of EGFP(+) PaSCs in injured mice. We propose that CCR2(+) monocytes migrate into the pancreas possibly via the MCP-1/CCR2 pathway and give rise to PaSCs.

Interleukin 17 (IL-17) is a pleiotropic cytokine that acts on both immune and non-immune cells and is generally implicated in inflammatory and autoimmune diseases. Although IL-17 as well as their source, mainly but not limited to Th17 cells, is also abundant in the inflamed intestine, the role of IL-17 in inflammatory bowel disease remains controversial. In the present study, by using IL-17 knockout (KO) mice, we investigated the role of IL-17 in colitis, with special focus on the macrophage subpopulations. Here we show that IL-17KO mice had increased susceptibility to DSS-induced colitis which was associated with decrease in expression of mRNAs implicated in M2 and/or wound healing macrophages, such as IL-10, IL-1 receptor antagonist, arginase 1, cyclooxygenase 2, and indoleamine 2,3-dioxygenase. Lamina propria leukocytes from inflamed colon of IL-17KO mice contained fewer CD11b+Ly6C+MHC Class II+ macrophages, which were derived, at least partly, from blood monocytes, as compared to those of WT mice. FACS-purified CD11b+ cells from WT mice, which were more abundant in Ly6C+MHC Class II+ cells, expressed increased levels of genes associated M2/wound healing macrophages and also M1/proinflammatory macrophages. Depletion of this population by topical administration of clodronate-liposome in the colon of WT mice resulted in the exacerbation of colitis. These results demonstrate that IL-17 confers protection against the development of severe colitis through the induction of an atypical M2-like macrophage subpopulation. Our findings reveal a previously unappreciated mechanism by which IL-17 exerts a protective function in colitis.