Antigen Delivery Systems: Past, Present, and Future

The COVID-19 pandemic has increased demand for safe and effective vaccines. Research to develop vaccines against diseases including Middle East respiratory syndrome, Ebolavirus, human immunodeficiency virus, and various cancers would also contribute to global well-being. For successful vaccine development, the advancement of technologies such as antigen (Ag) screening, Ag delivery systems and adjuvants, and manufacturing processes is essential. Ag delivery systems are required not only to deliver a sufficient amount of Ag for vaccination, but also to enhance immune response. In addition, Ag types and their delivery systems determine the manufacturing processes of the vaccine product. Here, we analyze the characteristics of various Ag delivery systems: plasmids, viral vectors, bacterial vectors, nanoparticles, self-assembled particles, natural and artificial cells, and extracellular vesicles. This review provides insight into the current vaccine landscape and highlights promising avenues of research for the development and improvement of Ag delivery systems.

Circulating Tumor DNA–Based Genotyping and Monitoring for Predicting Disease Relapses of Patients with Peripheral T-Cell Lymphomas / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Plasma circulating tumor DNA (ctDNA) could reflect the genetic alterations present in tumor tissues. However, there is little information about the clinical relevance of cell-free DNA genotyping in peripheral T-cell lymphoma (PTCL). @*Materials and Methods@#After targeted sequencing plasma cell-free DNA of patients with various subtypes of PTCL (n=94), we analyzed the mutation profiles of plasma ctDNA samples and their predictive value of dynamic ctDNA monitoring for treatment outcomes. @*Results@#Plasma ctDNA mutations were detected in 53 patients (56%, 53/94), and the detection rate of somatic mutations was highest in angioimmunoblastic T-cell lymphoma (24/31, 77%) and PTCL, not otherwise specified (18/29, 62.1%). Somatic mutations were detected in 51 of 66 genes that were sequenced, including the following top 10 ranked genes: RHOA, CREBBP, KMT2D, TP53, IDH2, ALK, MEF2B, SOCS1, CARD11, and KRAS. In the longitudinal assessment of ctDNA mutation, the difference in ctDNA mutation volume after treatment showed a significant correlation with disease relapse or progression. Thus, a ≥ 1.5-log decrease in genome equivalent (GE) between baseline and the end of treatment showed a significant association with better survival outcomes than a < 1.5-log decrease in GE. @*Conclusion@#Our results suggest the clinical relevance of plasma ctDNA analysis in patients with PTCL. However, our findings should be validated by a subsequent study with a larger study population and using a broader gene panel.

Targeted Liquid Biopsy Using Irradiation to Facilitate the Release of Cell-Free DNA from a Spatially Aimed Tumor Tissue / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We investigated the feasibility of using an anatomically localized, target-enriched liquid biopsy (TLB) in mouse models of lung cancer. @*Materials and Methods@#After irradiating xenograft mouse with human lung cancer cell lines, H1299 (NRAS proto-oncogene, GTPase [NRAS] Q61K) and HCC827 (epidermal growth factor receptor [EGFR] E746-750del), circulating (cell-free) tumor DNA (ctDNA) levels were monitored with quantitative polymerase chain reaction on human long interspersed nuclear element-1 and cell line-specific mutations. We checked dose-dependency at 6, 12, or 18 Gy to each tumor-bearing mouse leg using 6-MV photon beams. We also analyzed ctDNA of lung cancer patients by LiquidSCAN, a targeted deep sequencing to validated the clinical performances of TLB method. @*Results@#Irradiation could enhance the detection sensitivity of NRAS Q61K in the plasma sample of H1299-xenograft mouse to 4.5- fold. While cell-free DNA (cfDNA) level was not changed at 6 Gy, ctDNA level was increased upon irradiation. Using double-xenograft mouse with H1299 and HCC827, ctDNA polymerase chain reaction analysis with local irradiation in each region could specify mutation type matched to transplanted cell types, proposing an anatomically localized, TLB. Furthermore, when we performed targeted deep sequencing of cfDNA to monitor ctDNA level in 11 patients with lung cancer who underwent radiotherapy, the average ctDNA level was increased within a week after the start of radiotherapy. @*Conclusion@#TLB using irradiation could temporarily amplify ctDNA release in xenograft mouse and lung cancer patients, which enables us to develop theragnostic method for cancer patients with accurate ctDNA detection.

Plasma Circulating Tumor DNA in Patients with Primary Central Nervous System Lymphoma / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Analysis of circulating tumor DNA (ctDNA) in blood could allow noninvasive genetic analysis of primary tumors. Although there have been unmet needs for noninvasive methods in patients with primary central nervous system lymphoma (PCNSL), it is still not determined whether plasma ctDNA analysis could be useful for patients with PCNSL. @*Materials and Methods@#Targeted deep sequencing of 54 genes was performed in cell-free DNA isolated from plasma samples collected pretreatment, during treatment, and at the end of treatment in 42 consecutively diagnosed PCNSL patients between January 2017 and December 2018. @*Results@#Targeted sequencing of plasma cell-free DNA detected somatic mutations representing ctDNA in 11 cases (11/41, 27%). The detection of ctDNA was not related to the concentration of cell-free DNA or tumor volume. The mutation profiles of these 11 cases varied between patients. The most frequently mutated gene was PIM1 (4/11, 36.4%), whereas KMT2D, PIK3CA, and MYD88 were each observed in three patients (3/11, 27%). The mutations of 13 genes were concordantly found in primary tumor tissue and plasma ctDNA, giving a detection sensitivity of 45%. During the serial tracking of seven patients with complete response, the disappearance of ctDNA mutations was found in four patients, whereas three patients had detected ctDNA mutation at the end of treatment. @*Conclusion@#The plasma ctDNA mutation analysis still has limited value for surveillance and predicting treatment outcomes of PCNSL because the detection efficiency was lower than other systemic lymphomas. Thus, analytical platforms should be improved to overcome anatomical hurdles associated with PCNSL.

A Comparison of the Perception of and Adherence to the COVID-19 Social Distancing Behavior Guidelines among Health Care Workers, Patients, and General Public

Purpose@#To identify the differences in perception of and adherence to the COVID-19 social distancing behavior guidelines among health care workers, patients, and the general public and to use them to prevent the spread of COVID-19. @*Methods@#From October 16 2020 to November 30, 2020, a survey was conducted among 85 health care workers, 85 patients, and 82 general public regarding the perception of and adherence to the COVID-19 social distancing behavior guidelines. @*Results@#Patients scored significantly higher than the general public in the adherence to the COVID-19 social distancing behavior guideline, and there was no difference between health care workers and general public, and patients and health care workers. In the multivariate analysis, the factors that influence the adherence of the COVID-19 social distancing behavior guide were found in women and the perception of the COVID-19 social distancing behavior guideline. @*Conclusion@#In order to promote the implementation of the COVID-19 social distancing behavior guideline, it is necessary to increase the perception of the COVID-19 social distancing behavior guideline and provide additional education in men. It is necessary to investigate the reason behind why men have low adherence to the COVID-19 social distancing behavior guideline.

Outcomes after Cataract Surgery in High Myopes with Axial Length Differences of ≥2 mm

Purpose@#To evaluate the visual outcome after cataract operations in high myopia patients, whose axial length differences are longer than 2 mm. @*Methods@#A retrospective study was conducted on patients who had received phacoemulsification cataract surgery from January 2014 to June 2020. The patients whose axial lengths and inter-eye axial lengths exceeded 26 and 2 mm, respectively, were selected. Demographic data, axial lengths, central subfield macular thickness, retinal nerve fiber layer, and best-corrected visual acuities (BCVAs) before and at 6 months postoperatively were collected. The factors related to visual outcome were analyzed using univariate, multivariate linear regression. @*Results@#Twelve patients had an inter-eye axial length difference longer than 2 mm. The average axial lengths of longer and shorter eyes were 29.17 ± 1.94 and 26.66 ± 2.51 mm, respectively (p = 0.02, Mann-Whitney U-test). The BCVAs (logarithm of minimal angle of resolution, logMAR) of the longer and shorter eyes before the surgery were 1.09 ± 0.62 and 0.19 ± 0.16, respectively (p = 0.03, Mann-Whitney U-test). The BCVAs (logMAR) of the longer and shorter eyes 6 months after surgery were 0.19 ± 0.16 and 0.08 ± 0.10, respectively (p = 0.11, Mann-Whitney U-test). In univariate linear regression analysis, the BCVAs 6 months after the surgery showed better preoperative BCVAs (p < 0.001) and a thinner central subfield macular thickness (p = 0.001). In multivariate linear regression analysis, the BCVA at 6 months after the surgery showed significant improvement compared with preoperative BCVA values (p < 0.001). @*Conclusions@#High myopia patients whose axial length differences exceeded 2 mm showed improved VA after cataract surgery.

Psychological Insulin Resistance: Key Factors and Intervention / 임상당뇨병

Insulin is a mainstay of treatment in patients with type 2 diabetes mellitus to control blood sugar levels and reduce the risk of diabetes complications, but psychological insulin resistance can delay insulin treatment. Psychological insulin resistance can be defined as a negative attitude and feelings toward insulin treatment experienced by diabetics. Factors influencing psychological insulin resistance include a lack of understanding of diabetic pathophysiology, a negative attitude toward insulin treatment, anxiety about insulin therapy complications and hypoglycemia, distorted beliefs, daily constraints, fear or pain from injections, and discomfort. Various approaches to psychological insulin resistance involve direct demonstration of the insulin administration processes, education regarding diabetic pathophysiology and insulin action, assessment and evaluation of the degree of psychological insulin resistance, patient group training, building correct support systems, and providing contacts (e.g., diabetes center, diabetes nurse educator). The role of healthcare providers is important in reducing patients’ psychological insulin resistance through various interventions.

Work Experience of Nurses in Charge of Adequacy Evaluation of Small and Medium Sized Hospitals / 중환자간호학회지

Purpose@#: This study aimed to comprehensively understand the work experience of the person in charge of the adequacy evaluation of small-and medium-sized hospitals and explore its meaning and essence in-depth. @*Methods@#: This was a descriptive qualitative study. The study participants were 10 nurses who understood the purpose of this study and participated voluntarily. Data collection was conducted via in-depth interviews in January 2021. The interviews were conducted 1-2 times per participant and lasted approximately 40-50 minutes per session. Data analysis was performed using a qualitative content analysis. @*Results@#: The work experience of the person in charge of the adequacy evaluation of small-and medium-sized hospitals included four themes: “difficulty in preparing for evaluation,” “negative views on evaluation,” “lack of a support system,” and “positive improvements and changes due to an evaluation.” @*Conclusion@#: Based on the above results, an education program and support system should be developed to strengthen the competence of nurses in charge of the adequacy evaluation of small- and medium-sized hospitals.

Outcomes after Cataract Surgery in High Myopes with Axial Length Differences of ≥2 mm

Purpose@#To evaluate the visual outcome after cataract operations in high myopia patients, whose axial length differences are longer than 2 mm. @*Methods@#A retrospective study was conducted on patients who had received phacoemulsification cataract surgery from January 2014 to June 2020. The patients whose axial lengths and inter-eye axial lengths exceeded 26 and 2 mm, respectively, were selected. Demographic data, axial lengths, central subfield macular thickness, retinal nerve fiber layer, and best-corrected visual acuities (BCVAs) before and at 6 months postoperatively were collected. The factors related to visual outcome were analyzed using univariate, multivariate linear regression. @*Results@#Twelve patients had an inter-eye axial length difference longer than 2 mm. The average axial lengths of longer and shorter eyes were 29.17 ± 1.94 and 26.66 ± 2.51 mm, respectively (p = 0.02, Mann-Whitney U-test). The BCVAs (logarithm of minimal angle of resolution, logMAR) of the longer and shorter eyes before the surgery were 1.09 ± 0.62 and 0.19 ± 0.16, respectively (p = 0.03, Mann-Whitney U-test). The BCVAs (logMAR) of the longer and shorter eyes 6 months after surgery were 0.19 ± 0.16 and 0.08 ± 0.10, respectively (p = 0.11, Mann-Whitney U-test). In univariate linear regression analysis, the BCVAs 6 months after the surgery showed better preoperative BCVAs (p < 0.001) and a thinner central subfield macular thickness (p = 0.001). In multivariate linear regression analysis, the BCVA at 6 months after the surgery showed significant improvement compared with preoperative BCVA values (p < 0.001). @*Conclusions@#High myopia patients whose axial length differences exceeded 2 mm showed improved VA after cataract surgery.

The Analysis of Self-Mutilation in Adolescence Based on the Theory of Mentalization: From Sukhvinder in the Novel ‘Casual Vacancy’

OBJECTIVES: Adolescence involves a number of developmental processes, as well as unique psychological characteristics and behaviors. An increased rate of internet and game addictions, school violence, and suicide may either represent aspects of adolescence or a psychopathological phenomenon. There is an urgent need to develop software programs that can prevent and resolve adolescent behavioral problems. We applied the mentalization theory to interpret and find solutions for problems faced by adolescent characters in literature. METHODS: In Joan Rowling's novel “Casual Vacancy,” Sukhvinder is a girl with problems representative of those encountered by modern adolescents; she is a victim of bullying and engages in self-mutilation. We targeted her problematic behaviors as representative of a prementalized state. RESULTS: Born into an upper-class English family with Pakistani origins, Sukhvinder, unlike her siblings, fails her parents' expectations. Whenever she faces a psychological crisis, she regresses into the teleological mode (the most primitive pre-mentalization stage) and regains her sense of self by cutting herself. After her friend's suicide, however, she begins to communicate with her parents and moves toward mentalization. CONCLUSION: By analyzing Sukhvinder's behavior, we assessed patterns of attachment, empathy, and mentalization, and identified corrective approaches for problematic behaviors. We believe that the presented interpretation may serve as a foundation for the development of models for understanding adolescent deviant behaviors.

A case of nizatidine-induced immediate hypersensitivity

Nizatidine is a histamine H₂ receptor antagonist that inhibits stomach acid production and is commonly used in the treatment of peptic ulcer and gastroesophageal reflux. H₂ receptor antagonists are typically well tolerated, and hypersensitivity reactions are rare. A 19-year-old woman developed urticaria 30 minutes after taking a drug containing nizatidine. Allergic reactions to nizatidine were confirmed via skin prick test, which also revealed cross-reactions to ranitidine. We believe that this is the first case report on immediate hypersensitivity to nizatidine in Korea.

Successful desensitization to fluconazole induced delayed hypersensitivity: A case report

Fluconazole is a triazole-based first-generation antifungal agent and has excellent effects on candidiasis and cryptococcosis. Hypersensitivity has been reported as a side effect of fluconazole. A 76-year-old female patient used fluconazole for consolidation therapy for cryptococcal meningitis, but showed delayed hypersensitivity with skin rashes and itching sensation of the whole body. For desensitization, was attempted by administering 12-step, 1:1 fluconazole solutions were administered intravenously at sequentially increasing infusion rates. After successful quick desensitization to fluconazole, fluconazole was continuously used as a consolidation therapy for cryptococcal meningitis. We herein report a case of delayed hypersensitivity reaction to fluconazole in consolidation therpy with cryptococcal meningitis who successfully completed desensitization.

Optimal First-line Eradication Regimens for Helicobacter pylori Infection in Patients with Clarithromycin Resistance: A Pilot Study

BACKGROUND/AIMS: Helicobacter pylori eradication rates using first-line treatment have decreased due to clarithromycin resistance. The aim of this study was to investigate optimal eradication regimens for patients with clarithromycin resistance in Korea. MATERIALS AND METHODS: A total of 72 patients with confirmed clarithromycin resistance were enrolled from August 2015 to July 2017. Patients were randomized to a 7-day bismuth quadruple therapy (BQT) regimen or a 7-day metronidazole triple therapy (MTT) regimen. Eradication was confirmed using the 13C-urea breath test. RESULTS: There were no differences in baseline characteristics between the groups. Intention-to-treat eradication rates were 77.8% for the BQT group and 66.7% for the MTT group (P=0.293). Per protocol eradication rates were 87.5% for the BQT group and 77.4% for the MTT group (P=0.292). Adverse events were more frequent in the BQT group. CONCLUSIONS: Eradication rates using MTT were comparable to those using BQT, and adverse events were less frequent in the MTT group. Thus, MTT may be considered as a first-line regimen for patients with clarithromycin resistance. Since this was a pilot study, a study with a large group is required.

Antiviral and Anti-Inflammatory Activities of Pochonin D, a Heat Shock Protein 90 Inhibitor, against Rhinovirus Infection

Human rhinoviruses (HRV) are one of the major causes of common cold in humans and are also associated with acute asthma and bronchial illness. Heat-shock protein 90 (Hsp90), a molecular chaperone, is an important host factor for the replication of single-strand RNA viruses. In the current study, we examined the effect of the Hsp90 inhibitor pochonin D, in vitro and in vivo, using a murine model of human rhinovirus type 1B (HRV1B) infection. Our data suggested that Hsp90 inhibition significantly reduced the inflammatory cytokine production and lung damage caused by HRV1B infection. The viral titer was significantly lowered in HRV1B-infected lungs and in Hela cells upon treatment with pochonin D. Infiltration of innate immune cells including granulocytes and monocytes was also reduced in the bronchoalveolar lavage (BAL) by pochonin D treatment after HRV1B infection. Histological analysis of the lung and respiratory tract showed that pochonin D protected the mice from HRV1B infection. Collectively, our results suggest that the Hsp90 inhibitor, pochonin D, could be an attractive antiviral therapeutic for treating HRV infection.

Complications of Cardiac Catheterization in Structural Heart Disease

BACKGROUND AND OBJECTIVES: Cardiac catheterization is used to diagnose structural heart disease (SHD) and perform transcatheter treatment. This study aimed to evaluate complications of cardiac catheterization and the associated risk factors in a tertiary center over 10 years. SUBJECTS AND METHODS: Total 2071 cardiac catheterizations performed at the Seoul National University Children's Hospital from January 2004 to December 2013 were included in this retrospective study. RESULTS: The overall complication, severe complication, and mortality rates were 16.2%, 1.15%, and 0.19%, respectively. The factors that significantly increased the risk of overall and severe complications were anticoagulant use before procedure (odds ratio [OR] 1.83, p=0.012 and OR 6.45, p<0.001, respectively), prothrombin time (OR 2.30, p<0.001 and OR 5.99, p<0.001, respectively), general anesthesia use during procedure (OR 1.84, p=0.014 and OR 5.31, p=0.015, respectively), and total procedure time (OR 1.01, p<0.001 and OR 1.02, p<0.001, respectively). Low body weight (OR 0.99, p=0.003), severe SHD (OR 1.37, p=0.012), repetitive procedures (OR 1.7, p=0.009), and total fluoroscopy time (OR 1.01, p=0.005) significantly increased the overall complication risk. High activated partial thromboplastin time (OR 1.04, p=0.001), intensive care unit admission state (OR 14.03, p<0.001), and concomitant electrophysiological study during procedure (OR 3.41, p=0.016) significantly increased severe complication risk. CONCLUSION: Currently, the use of cardiac catheterization in SHD is increasing and becoming more complex; this could cause complications despite the preventive efforts. Careful patient selection for therapeutic catheterization and improved technique and management during the peri-procedural period are required to reduce complications.

Mutation of the NF1 Gene and the Associated Clinical Features in Family Members with Neurofibromatosis Type 1 / 대한내과학회지

With an incidence of 1 per 2,500-3,000 individuals, neurofibromatosis type 1 (NF1) is the most common autosomal dominant disorder in humans. NF1 is caused by germline mutations of the NF1 gene, but to date genotype-phenotype analyses have indicated no clear relationship between specific gene mutations and the clinical features of this disease, even among family members with the same mutation. The present study describes a case of two siblings with NF1 with the same genetic mutation but different clinical manifestations. The first patient was a female with iris Lisch nodules, an adrenal incidentaloma, Graves' disease, and skin manifestations, while the second patient, the first patient's younger brother, exhibited only skin neurofibromas and freckling. Further study is needed to reveal the molecular processes underlying gene expression and phenotypes. A better understanding of the genetics associated with NF1 will allow clinicians to detect complications earlier and provide better genetic counseling to NF1 families.

CTHRC1 promotes angiogenesis by recruiting Tie2-expressing monocytes to pancreatic tumors

CTHRC1 (collagen triple-helix repeat-containing 1), a protein secreted during the tissue-repair process, is highly expressed in several malignant tumors, including pancreatic cancer. We recently showed that CTHRC1 has an important role in the progression and metastasis of pancreatic cancer. Although CTHRC1 secretion affects tumor cells, how it promotes tumorigenesis in the context of the microenvironment is largely unknown. Here we identified a novel role of CTHRC1 as a potent endothelial activator that promotes angiogenesis by recruiting bone marrow-derived cells to the tumor microenvironment during tumorigenesis. Recombinant CTHRC1 (rCTHRC1) enhanced endothelial cell (EC) proliferation, migration and capillary-like tube formation, which was consistent with the observed increases in neovascularization in vivo. Moreover, rCTHRC1 upregulated angiopoietin-2 (Ang-2), a Tie2 receptor ligand, through ERK-dependent activation of AP-1 in ECs, resulting in recruitment of Tie2-expressing monocytes (TEMs) to CTHRC1-overexpressing tumor tissues. Treatment with a CTHRC1-neutralizing antibody-abrogated Ang-2 expression in the ECs in vitro. Moreover, administration of a CTHRC1-neutralizing antibody to a xenograft mouse model reduced the tumor burden and infiltration of TEMs in the tumor tissues, indicating that blocking the CTHRC1/Ang-2/TEM axis during angiogenesis inhibits tumorigenesis. Collectively, our findings support the hypothesis that CTHRC1 induction of the Ang-2/Tie2 axis mediates the recruitment of TEMs, which are important for tumorigenesis and can be targeted to achieve effective antitumor responses in pancreatic cancers.

Infantile Marfan syndrome in a Korean tertiary referral center / 소아과

PURPOSE: Infantile Marfan syndrome (MFS) is a rare congenital inheritable connective tissue disorder with poor prognosis. This study aimed to evaluate the cardiovascular manifestations and overall prognosis of infantile MFS diagnosed in a tertiary referral center in Korea. METHODS: Eight patients diagnosed with infantile MFS between 2004 and 2014 were retrospectively evaluated. RESULTS: Their median age at the time of diagnosis was 2.5 months (range, 0-20 months). The median follow-up period was 25.5 months (range, 0-94 months). The median length at birth was 50.0 cm (range, 48-53 cm); however, height became more prominent over time, and the patients were taller than the 97th percentile at the time of the study. None of the patients had any relevant family history. Four of the 5 patients who underwent DNA sequencing had a fibrillin 1 gene mutation. All the patients with echocardiographic data of the aortic root had a z score of >2. All had mitral and tricuspid valve prolapse, and various degrees of mitral and tricuspid regurgitation. Five patients underwent open-heart surgery, including mitral valve replacement, of whom two required multiple operations. The median age at mitral valve replacement was 28.5 months (range, 5-69 months). Seven patients showed congestive heart failure before surgery or during follow-up, and required multiple anti-heart failure medications. Four patients died of heart failure at a median age of 12 months. CONCLUSION: The prognosis of infantile MFS is poor; thus, early diagnosis and timely cautious treatment are essential to prevent further morbidity and mortality.

Variable expression observed in a Korean family with Townes-Brocks syndrome caused by a SALL1 mutation

Townes-Brocks syndrome (TBS) is a rare genetic disorder characterized by the classic triad of congenital anomalies of the anus, thumbs, and ears, with variable expressivity. Additionally, renal malformations, cardiac anomalies, and endocrine and eye abnormalities can accompany TBS, although less frequently. TBS is inherited in an autosomal dominant fashion; however, about 50% of patients have a family history of TBS and the remaining 50% have de novo mutations. SALL1, located on chromosome 16q12.1, is the only causative gene of TBS. SALL1 acts as a transcription factor and may play an important role in inducing the anomalies during embryogenesis. Clinical features of TBS overlap with those of other multiple anomaly syndromes, such as VACTERL syndrome, Baller-Gerold syndrome, Goldenhar syndrome, cat eye syndrome, and Holt-Oram syndrome. Consequently, there are some difficulties in differential diagnosis based on clinical manifestations. Herein, we report a Korean family with two generations of TBS that was diagnosed based on physical examination findings and medical history. Although the same mutation in SALL1 was identified in both the mother and the son, they displayed different clinical manifestations, suggesting a phenotypic diversity of TBS.

Myeloid-Derived Suppressor Cells in Inflammatory Bowel Disease

Immature myeloid cells, also known as myeloid-derived suppressor cells (MDSCs), include neutrophilic and monocytic myeloid cells, and are found in inflammatory loci and secondary lymphoid organs in mice with intestinal inflammation, inflammatory bowel disease (IBD) patients, and tumor tissues. However, the roles of MDSCs in IBD are not yet well understood, and there are controversies regarding their immunosuppressive functions in IBD. In addition, recent studies have suggested that endoplasmic reticulum (ER) stress in intestinal epithelial cells, especially in Paneth cells, is closely associated with the induction of IBD. However, the ER stress in MDSCs accumulated in the inflamed tissues of IBD patients is not yet fully understood. In the current review, we discuss the presence of accumulated MDSCs in the intestines of IBD patients, and further speculate on their physiological roles in the inflammatory condition with interleukin 17-producing cells, including Th17 cells. In particular, we will discuss the divergent functions of MDSCs in ER stressed intestinal environments, including their pro-inflammatory or immunosuppressive roles, based on the consideration of unfolded protein responses initiated in intestinal epithelial cells by ER stress.