Investigation of immune-related diseases using patient-derived induced pluripotent stem cells.

The precise pathogenesis of immune-related diseases remains unclear, and new effective therapeutic choices are required for the induction of remission or cure in these diseases. Basic research utilizing immune-related disease patient-derived induced pluripotent stem (iPS) cells is expected to be a promising platform for elucidating the pathogenesis of the diseases and for drug discovery. Since autoinflammatory diseases are usually monogenic, genetic mutations affect the cell function and patient-derived iPS cells tend to exhibit disease-specific phenotypes. In particular, iPS cell-derived monocytic cells and macrophages can be used for functional experiments, such as inflammatory cytokine production, and are often employed in research on patients with autoinflammatory diseases.On the other hand, the utilization of disease-specific iPS cells is less successful for research on autoimmune diseases. One reason for this is that autoimmune diseases are usually polygenic, which makes it challenging to determine which factors cause the phenotypes of patient-derived iPS cells are caused by. Another reason is that protocols for differentiating some lymphocytes associated with autoimmunity, such as CD4+T cells or B cells, from iPS cells have not been well established. Nevertheless, several groups have reported studies utilizing autoimmune disease patient-derived iPS cells, including patients with rheumatoid arthritis, systemic lupus erythematosus (SLE), and systemic sclerosis. Particularly, non-hematopoietic cells, such as fibroblasts and cardiomyocytes, differentiated from autoimmune patient-derived iPS cells have shown promising results for further research into the pathogenesis. Recently, our groups established a method for differentiating dendritic cells that produce interferon-alpha, which can be applied as an SLE pathological model. In summary, patient-derived iPS cells can provide a promising platform for pathological research and new drug discovery in the field of immune-related diseases.

Nonepisodic Angioedema with Eosinophilia Following Receipt of the BNT162b2 mRNA COVID-19 Vaccine.

Angioedema with eosinophilia (AE) is a rare disease of unknown etiology characterized by episodic (EAE) or nonepisodic AE (NEAE). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA-based vaccines function as immunogens and intrinsic adjuvants and have been shown to be safe in large-scale trials. However, the long-term adverse reactions, especially those related to eosinophilic complications, have not been fully clarified. We herein report a case of self-limited but severe NEAE that developed in a young woman one week after receiving the second BNT162b2 mRNA vaccine. The symptoms that impaired her activities of daily living, such as edema, gradually resolved with supportive care over 10 weeks without corticosteroid treatment.

Functional evaluation of rare OASL variants by analysis of SLE patient-derived iPSCs.

BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by genetic heterogeneity and an interferon (IFN) signature. The overall landscapes of the heritability of SLE remains unclear. OBJECTIVES: To identify and elucidate the biological functions of rare variants underlying SLE, we conducted analyses of patient-derived induced pluripotent stem cells (iPSCs) in combination with genetic analysis. METHODS: Two familial SLE patient- and two healthy donor (HD)-derived iPSCs were established. Type 1 IFN-secreting dendritic cells (DCs) were differentiated from iPSCs. Genetic analyses of SLE-iPSCs, and 117 SLE patients and 107 HDs in the ImmuNexUT database were performed independently. Genome editing of the variants on iPSCs was performed with the CRISPR/Cas9 system. RESULTS: Type 1 IFN secretion was significantly increased in DCs differentiated from SLE-iPSCs compared to HD-iPSCs. Genetic analyses revealed a rare variant in the 2'-5'-Oligoadenylate Synthetase Like (OASL) shared between SLE-iPSCs and another independent SLE patient, and significant accumulation of OASL variants among SLE patients (HD 0.93%, SLE 6.84%, OR 8.387) in the database. Genome editing of mutated OASL 202Q to wild-type 202 R or wild-type OASL 202 R to mutated 202Q resulted in reduced or enhanced Type 1 IFN secretion of DCs. Three other OASL variants (R60W, T261S and A447V) accumulated in SLE patients had also capacities to enhance Type 1 IFN secretion in response to dsRNA. CONCLUSIONS: We established a patient-derived iPSC-based strategy to investigate the linkage of genotype and phenotype in autoimmune diseases. Detailed case-based investigations using patient-derived iPSCs provide information to unveil the heritability of the pathogenesis of autoimmune diseases.

Pulmonary Hypertension Associated with Anti-synthetase Syndrome: A Case Report and Literature Review.

Pulmonary hypertension (PH) is a serious condition in which there is an abnormally high pressure in the pulmonary arteries that can occur as a complication of connective tissue diseases. Although the relationship between PH and systemic lupus erythematosus or systemic sclerosis has been well-characterized, PH rarely occurs in patients with anti-synthetase syndrome (ASS), and little is known about the pathophysiology and clinical outcome of patients with ASS-PH. We herein report a patient with anti-Jo-1-positive ASS complicated by PH and discuss the treatment strategy through a review of previously reported cases.

Self-limited Polymyalgia Rheumatica-like Syndrome Following mRNA-1273 SARS-CoV-2 Vaccination.

Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease characterized by stiffness and aching mainly in the shoulders, neck and hip girdles. The underlying pathogenesis of PMR involves myeloid lineage activation with a high expression of pattern recognition receptors. In addition, vaccination against severe acute respiratory syndrome coronavirus 2 with mRNA-1273 functions as both an immunogen and intrinsic adjuvant. It leads to the activation of innate immunity, resulting in antibody production. We herein report the first case of PMR-like syndrome seven days after mRNA-1273 vaccination. Reassuringly, the symptoms, such as pain of the neck, shoulder girdle and pelvic girdle, as well as elevated inflammatory markers were resolved within a month without glucocorticoid or immunosuppressant administration.

Immature platelet levels correlate with disease activity and predict treatment response of thrombocytopenia in lupus patients.

OBJECTIVE: The immature platelet fraction (IPF) represents recently produced platelets in bone marrow and this parameter is increased in patient with primary immune thrombocytopenia (ITP). We investigated the associations between IPF and absolute immature platelet count (AIPC), and clinical parameters in systemic lupus erythematosus (SLE), which has more complex pathological mechanisms than in primary ITP. METHODS: Patients with SLE were retrospectively reviewed at the University of Tokyo Hospital from May, 2012 to January, 2021. The correlations between clinical parameters and the number of immature platelets were assessed with Spearman's rank correlation coefficients. A multiple logistic regression model was used to identify the independent clinical parameters for IPF and AIPC. The difference in the distribution of time for a complete response (CR) after prednisolone (PSL) administration was also evaluated by log-rank test. RESULTS: A total of 282 SLE patients were enrolled, and 12.41% of those patients showed thrombocytopenia. IPF correlated with clinical parameters such as platelet count (r = -0.58), AIPC (r = 0.64) and systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K) (r = 0.24). SLEDAI-2K [odds ratio (OR) (per unit increase), 1.07; 95% CI, 1.013 - 1.13] and thrombocytopenia (OR, 32.23; 95% CI, 11.072 - 93.80) were independent clinical parameters to account for IPF increase. IPF correlated with the number of bone marrow megakaryocytes (n = 19, r = 0.57). Notably, the probability of CR in response to PSL in AIPC-high patients was higher than in AIPC-low patients (hazard ratio, 4.62; 95% CI, 1.07 - 20.02). CONCLUSION: IPF correlated with disease activity of SLE and represented platelet production in the bone marrow, whereas AIPC predicted a rapid response to steroids in thrombocytopenic patients with SLE.

Robust and highly efficient hiPSC generation from patient non-mobilized peripheral blood-derived CD34+ cells using the auto-erasable Sendai virus vector.

BACKGROUND: Disease modeling with patient-derived induced pluripotent stem cells (iPSCs) is a powerful tool for elucidating the mechanisms underlying disease pathogenesis and developing safe and effective treatments. Patient peripheral blood (PB) cells are used for iPSC generation in many cases since they can be collected with minimum invasiveness. To derive iPSCs that lack immunoreceptor gene rearrangements, hematopoietic stem and progenitor cells (HSPCs) are often targeted as the reprogramming source. However, the current protocols generally require HSPC mobilization and/or ex vivo expansion owing to their sparsity at the steady state and low reprogramming efficiencies, making the overall procedure costly, laborious, and time-consuming. METHODS: We have established a highly efficient method for generating iPSCs from non-mobilized PB-derived CD34+ HSPCs. The source PB mononuclear cells were obtained from 1 healthy donor and 15 patients and were kept frozen until the scheduled iPSC generation. CD34+ HSPC enrichment was done using immunomagnetic beads, with no ex vivo expansion culture. To reprogram the CD34+-rich cells to pluripotency, the Sendai virus vector SeVdp-302L was used to transfer four transcription factors: KLF4, OCT4, SOX2, and c-MYC. In this iPSC generation series, the reprogramming efficiencies, success rates of iPSC line establishment, and progression time were recorded. After generating the iPSC frozen stocks, the cell recovery and their residual transgenes, karyotypes, T cell receptor gene rearrangement, pluripotency markers, and differentiation capability were examined. RESULTS: We succeeded in establishing 223 iPSC lines with high reprogramming efficiencies from 15 patients with 8 different disease types. Our method allowed the rapid appearance of primary colonies (~ 8 days), all of which were expandable under feeder-free conditions, enabling robust establishment steps with less workload. After thawing, the established iPSC lines were verified to be pluripotency marker-positive and of non-T cell origin. A majority of the iPSC lines were confirmed to be transgene-free, with normal karyotypes. Their trilineage differentiation capability was also verified in a defined in vitro assay. CONCLUSION: This robust and highly efficient method enables the rapid and cost-effective establishment of transgene-free iPSC lines from a small volume of PB, thus facilitating the biobanking of patient-derived iPSCs and their use for the modeling of various diseases.

New horizons in clinical immunology: applications of induced pluripotent stem cells for the analysis of immune disorders.

The discovery of induced pluripotent stem cells (iPSCs) has diversified approaches to studies of human diseases. iPSCs can be used in regenerative medicine and for the analysis of the pathogenesis of hereditary diseases. They can also be applied to research on immune disorders, including the influence of genetic factors on autoimmune diseases in the human system. Some immune cells, such as dendritic cells and macrophages, can be differentiated from iPSCs. Thus, immune disorders caused by defects in the innate immune system can be studied with that approach. We propose that biological mechanisms of genetic risks could be examined by mutating or modifying disease-susceptibility genes in iPSCs by genome editing. Studies using human iPSCs are also expected to elucidate the underlying pathogenesis of immunological diseases and new approaches to drug discovery.

Investigation of the pathogenesis of autoimmune diseases by iPS cells.

The pluripotent stem cells have a self-renewal ability and can be differentiated into theoretically all of cell types. The induced pluripotent stem (iPS) cells overcame the ethical problems of the human embryonic stem (ES) cell, and enable pathologic analysis of intractable diseases and drug discovery. The in vitro disease model using disease-specific iPS cells enables repeated analyses of human cells without influence of environment factors. Even though autoimmune diseases are polygenic diseases, autoimmune disease-specific iPS cells are thought to be a promising tool for analyzing the pathogenesis of the diseases and drug discovery in future.