Impact of perineal pain and delivery related factors on interference with activities of daily living until 1 month postpartum: A longitudinal prospective study.

BACKGROUND: Interference with activities of daily living can negatively impact maternal practices both physically and psychologically. This study aimed to explore the patterns of interference with activities of daily living and perineal pain among Japanese women until 1 month postpartum. Furthermore, we aimed to describe how both perineal pain and delivery-related factors were associated with interference with activities of daily living. METHODS: This study was part of a larger prospective longitudinal study conducted at five maternity hospitals in Japan. The participants were 293 women who had full-term vaginal deliveries and singleton infants. Participants self-evaluated their perineal pain and interference with activities of daily living using a 100 mm visual analogue scale and 'behaviour that interferes with daily life scale' at day 1, day 5, and 1 month postpartum. We used a linear mixed model to calculate the fixed-effects parameter estimates and their 95% confidence intervals. Interference with activities of daily living, which included difficulty sitting, difficulty moving, and difficulties with excretion and cleanliness, were set as the dependent variables. RESULTS: The final analysis included 184 participants with a mean age of 31.5±4.5 years. Perineal pain and the three sub-scales of interference with activities of daily living reduced from day 1 to 5 postpartum, and further from day 5 to 1 month postpartum (perineal pain, p<0.01, p<0.01; difficulty sitting, p<0.01, p<0.01; difficulty moving, p<0.01, p<0.01; difficulties with excretion and cleanliness, p<0.01, p<0.01). These tendencies did not change, even adjusted for independent variables using a mixed model. In the mixed model for follow-up data, perineal pain was a significantly and positively associated with three sub-scales of interference with activities of daily living, even after adjusted for perineal injury and episiotomy. CONCLUSIONS: Positive relationships were observed between perineal pain and interference with activities of daily living until 1 month postpartum, although both reduced. To promote maternal role attainment through child-rearing since early postpartum, midwives should pay additional attention to mothers' perineal pain as it could negatively affect their daily life and child-rearing.

Longitudinal Analysis of Mitochondrial Function in a Choline-Deficient L-Amino Acid-Defined High-Fat Diet-Induced Metabolic Dysfunction-Associated Steatohepatitis Mouse Model.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases worldwide. Some patients with MAFLD develop metabolic dysfunction-associated steatohepatitis (MASH), which can lead to severe liver fibrosis. However, the molecular mechanisms underlying this progression remain unknown, and no effective treatment for MASH has been developed so far. In this study, we performed a longitudinal detailed analysis of mitochondria in the livers of choline-deficient, methionine-defined, high-fat-diet (CDAHFD)-fed mice, which exhibited a MASH-like pathology. We found that FoF1-ATPase activity began to decrease in the mitochondria of CDAHFD-fed mice prior to alterations in the activity of mitochondrial respiratory chain complex, almost at the time of onset of liver fibrosis. In addition, the decrease in FoF1-ATPase activity coincided with the accelerated opening of the mitochondrial permeability transition pore (PTP), for which FoF1-ATPase might be a major component or regulator. As fibrosis progressed, mitochondrial permeability transition (PT) induced in CDAHFD-fed mice became less sensitive to cyclosporine A, a specific PT inhibitor. These results suggest that episodes of fibrosis might be related to the disruption of mitochondrial function via PTP opening, which is triggered by functional changes in FoF1-ATPase. These novel findings could help elucidate the pathogenesis of MASH and lead to the development of new therapeutic strategies.

[Ovarian hyperstimulation syndrome with controlled ovarian stimulation after induction therapy for Philadelphia chromosome-positive acute lymphoblastic leukemia].

A 27-year-old woman with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia received induction therapy with dasatinib and prednisolone. From the time of diagnosis, oocyte storage was planned in accordance with the patient's wishes. After progesterone administration for suppression of menstruation, and blood cell recovery, ovarian stimulation was performed and a sufficient number of eggs was collected. The patient was considered at high risk for ovarian stimulation syndrome (OHSS) and received cabergoline and letrozole. However, ovarian enlargement and ascites were observed on ultrasonography 2 days after egg collection, and a diagnosis of moderate OHSS was made. Circulatory management was performed and low-molecular-weight heparin was administered. Dasatinib was discontinued due to the appearance of pleural effusion. Fluid retention improved after menstruation resumed, and the patient was able to continue consolidation with dasatinib and cord blood transplantation. Although tyrosine kinase inhibitors are expected to simplify planning of oocyte storage, the risk of complicating OHSS should be noted.

[Desquamative esophagitis associated with unrelated allogeneic peripheral blood stem cell transplantation using the FBM conditioning regimen].

Desquamative esophagitis (DE) is a rare benign condition characterized by sheet-like shedding of esophageal squamous epithelial tissue. Although cases of drug-induced DE, such as those induced by direct oral anticoagulants, have been reported, cases of DE complicated with hematopoietic stem cell transplantation (HSCT) are rare. We herein report the case of a 52-year-old woman with FLT3-ITD mutation-positive acute myeloid leukemia who presented with DE immediately after HSCT. Allogeneic peripheral blood HSCT with FBM (fludarabine 180 mg/m2, busulfan 12.8 mg/m2, and melphalan 80 mg/m2) was performed during the first remission. Tacrolimus plus short-term methotrexate was planned for graft-versus-host disease prevention. Common Terminology Criteria for Adverse Events grade 3 equivalent vomiting was observed during treatment with the conditioning regimen. On day 5 after HSCT, a white band of 10 cm in length and 1 cm in width was discharged from the oral cavity during vomiting. Upper gastrointestinal endoscopy revealed mucosal detachment in the entire esophagus and the diagnosis of DE was made. DE improved on providing conservative treatment. We concluded that the mechanical pressure that developed on the esophagus due to frequent vomiting contributed to the mucosal detachment owing to regimen-related toxicity. Even in the FBM regimen, which is widely used as a conditioning regimen, caution is required to prevent DE.

Elevation of HHV-6 viral load mimicking HHV-6 reactivation after second umbilical cord blood transplantation in chromosomally integrated human herpesvirus-6.

Human herpesvirus-6 (HHV-6) reactivation is an important complication in patients receiving umbilical cord blood transplantation (CBT). Chromosomally integrated human herpesvirus-6 (ciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the host germline genome and is transmitted in a Mendelian manner. The influence of ciHHV-6 in recipients or donors in cases of CBT is unknown. We report the first case with ciHHV-6 that received CBT twice for acute lymphoblastic T-cell leukemia. HHV-6 DNA in peripheral blood leukocytes (PBLs) was examined over time through two CBTs. After the first CBT, the HHV-6 viral load was significantly reduced by conversion to PBLs derived from the first donor. During the second CBT, an increase in HHV-6 DNA in PBLs and plasma were observed. However, HHV-6 mRNA was not detected in either the sample before 2nd CBT or at the time of HHV-6 DNA elevation. It is considered that the HHV-6 DNA detected in PBLs and plasma samples might be the HHV-6 genome released due to tissue damage. This case suggests that physicians should be aware of HHV-6 DNA variability during allogeneic hematopoietic stem cell transplantation in ciHHV-6 patients.

Epstein-Barr virus-associated post-transplant lymphoproliferative disease during dasatinib treatment occurred 10 years after umbilical cord blood transplantation.

Post-transplant lymphoproliferative disease (PTLD) is defined as a lymphoma that occurs after solid-organ or hematopoietic stem-cell transplantation (HSCT), caused by immunosuppression and Epstein-Barr virus (EBV) reactivation. It is an important post-transplant complication that can be fatal. After HSCT, most PTLD occurs within 2 years. Recent evidence suggests that tyrosine kinase inhibitors (TKIs) are expected to be effective maintenance therapy after HSCT for Philadelphia chromosome-positive leukemia. However, it is unclear whether the use of TKIs might pose a risk of developing PTLD after HSCT. We present the first case of late-onset PTLD during dasatinib treatment, which occurred 10 years after umbilical cord blood transplantation (CBT). A 59-year-old man who received CBT for chronic myeloid leukemia blast phase needed long-term dasatinib therapy for molecular relapse. Ten years after CBT, he developed diffuse-large B-cell lymphoma (DLBCL). We observed chimerism of the DLBCL sample, which indicated complete donor type and EBV-DNA, and the patient was diagnosed with PTLD. Because of treatment resistance, he died 6 months after PTLD onset. Although he received no long-term administration of immunosuppressive agents, he received long-term dasatinib treatment, which suggests that prolonged dasatinib use after CBT caused EBV reactivation and led to PTLD. Our case suggests that the potential contribution of molecular-targeted agents after HSCT to the development of PTLD should be carefully considered.

Achaete-Scute Homologue 2-Regulated Follicular Helper T Cells Promote Autoimmunity in a Murine Model for Sjögren Syndrome.

Follicular helper T (Tfh) cells contribute to various immune responses as well as to the pathogenesis of several immune diseases. However, the precise mechanism underlying the onset or development of autoimmunity via Tfh cells remains unclear. Herein, the detailed relationship between autoimmune disease and Tfh cells was analyzed using a murine model for Sjögren syndrome (SS) wherein the mice underwent neonatal thymectomy. Germinal center (GC) development was promoted in this SS model along with an increase of Tfh cells and GC B cells. The severity of the autoimmune lesions was correlated with the number of Tfh cells detected in the spleen of the SS model mice. In addition, treatment with an anti-CD20 monoclonal antibody effectively suppressed the autoimmune lesions with a reduction of Tfh cells and GC B cells. Comprehensive gene analysis revealed that several genes associated with Tfh cell differentiation, including achaete-scute homologue 2 (Ascl2), were up-regulated in peripheral CD25- CD4+ T cells in SS model mice compared with those in control mice. Moreover, an experiment using CD4CreBcl6fl/fl mice that received neonatal thymectomy treatment demonstrated that Ascl2 contributes to the Tfh cell differentiation associated with autoimmunity during the early stages, independent of Bcl6. In conclusion, our results indicate that abnormal Tfh cell differentiation via Ascl2 regulation might contribute to the pathogenesis of autoimmunity.

[Persistent malnutrition caused by Nihonkaiense diphyllobothriasis diagnosed during treatment of malignant lymphoma].

A 72-year-old man with ileocecal lymphadenopathy was found to have Epstein-Barr virus-positive diffuse large B-cell lymphoma using open biopsy, and an ileostoma was created. R-CHOP-like chemotherapy was initiated, but his malnutrition did not improve. After 3 cycles of chemotherapy, a 2-m-long Cestoda was removed from the stoma and was identified as Diphyllobothrium nihonkaiense using mitochondria cytochrome c oxidase subunit 1 targeted polymerase chain reaction analysis. Although D. nihonkaiense infections are asymptomatic, the ileostomy was thought to have exacerbated the malabsorption in this patient. Parasitic infections are rare; however, they should be added to the differential diagnosis of malnutrition of unknown cause during chemotherapy for hematological malignancies.

Polyethyleneimine renders mitochondrial membranes permeable by interacting with negatively charged phospholipids in them.

Polyethyleneimines (PEIs) are used for transfection of cells with nucleic acids. Meanwhile, the interaction of PEI with mitochondria causes cytochrome c release prior to apoptosis; the mechanisms how PEI causes this permeabilization of mitochondrial membranes and the release of cytochrome c remain unclear. To clarify these mechanisms, we examined the effects of branched-type PEI and linear-type PEI, each of which was 25 kDa in size, on mitochondria. The permeabilization potency of mitochondrial membranes by branched PEI was stronger than that by linear PEI. The permeabilization by PEIs were insensitive to permeability-transition inhibitors, indicating that PEI-induced permeabilization was not attributed to permeability transition. Meanwhile, PEIs caused permeabilization of artificial lipid vesicles; again, the permeabilization potency of branched PEI was stronger than that of linear PEI. Such a difference in this potency was close to that in the case of isolated mitochondria, signifying that the PEI-induced permeabilization of mitochondrial membranes could be attributed to PEI's interaction with the phospholipid phase. Furthermore, this PEI-induced permeabilization of the lipid vesicles was observed only in the case of lipid vesicles including negatively charged phospholipids. These results indicate that PEIs interacted with negatively charged phospholipids in the mitochondrial membranes to directly lead to their permeabilization.

The Association Between Metabolically Healthy Obesity and the Risk of Proteinuria: The Kansai Healthcare Study.

BACKGROUND: Metabolically healthy obesity seems to be a unique phenotype for the risk of cardiometabolic diseases. However, it is not known whether this phenotype is associated with the risk of proteinuria. METHODS: Study subjects were 9,185 non-diabetic Japanese male workers aged 40-55 years who had no proteinuria, an estimated glomerular filtration rate ≥60 mL/min/1.73 m2, no history of cancer, and no use of antihypertensive or lipid-lowering medications at baseline. Obesity was defined as body mass index ≥25.0 kg/m2. Metabolic health was defined as the presence of no Adult Treatment Panel III components of the metabolic syndrome criteria, excluding waist circumference, and metabolic unhealth was defined as the presence of one or more metabolic syndrome components, excluding waist circumference. "Consecutive proteinuria" was considered positive if proteinuria was detected twice consecutively as 1+ or higher on urine dipstick at annual examinations to exclude chance proteinuria as much as possible. RESULTS: During the 81,660 person-years follow-up period, we confirmed 390 cases of consecutive proteinuria. Compared with metabolically healthy non-obesity, metabolically healthy obesity was not associated with the risk of consecutive proteinuria (multiple-adjusted hazard ratio [HR] 0.86; 95% confidence interval [CI], 0.37-1.99), but metabolically unhealthy non-obesity with ≥2 metabolic syndrome components (HR 1.77; 95% CI, 1.30-2.42), metabolically unhealthy obesity with one component (HR 1.71; 95% CI, 1.12-2.61), and metabolically unhealthy obesity with ≥2 metabolic syndrome components (HR 2.77; 95% CI, 2.01-3.82) were associated with an increased risk of consecutive proteinuria. CONCLUSIONS: Metabolically healthy obesity did not increase the risk of consecutive proteinuria in Japanese middle-aged men.

Analysis of the structure and function of EMRE in a yeast expression system.

The mitochondrial calcium uniporter (MCU) complex is a highly-selective calcium channel, and this complex is believed to consist of a pore-forming subunit, MCU, and its regulatory subunits. As yeast cells lack orthologues of the mammalian proteins, the yeast expression system for the mammalian calcium uniporter subunits is useful for investigating their functions. We here established a yeast expression system for the native-form mouse MCU and 4 other subunits. This expression system enabled us to precisely reconstitute the properties of the mammalian MCU complex in yeast mitochondria. Using this expression system, we analyzed the essential MCU regulator (EMRE), which is a key subunit for Ca(2+) uptake but whose functions and structure remain unclear. The topology of EMRE was revealed: its N- and C-termini projected into the matrix and the inter membrane space, respectively. The expression of EMRE alone was insufficient for Ca(2+) uptake; and co-expression of MCU with EMRE was necessary. EMRE was independent of the protein levels of other subunits, indicating that EMRE was not a protein-stabilizing factor. Deletion of acidic amino acids conserved in EMRE did not significantly affect Ca(2+) uptake; thus, EMRE did not have basic properties of ion channels such as ion-selectivity filtration and ion concentration. Meanwhile, EMRE closely interacted with the MCU on both sides of the inner membrane, and this interaction was essential for Ca(2+) uptake. This close interaction suggested that EMRE might be a structural factor for opening of the MCU-forming pore.

Pathological Analysis of Ocular Lesions in a Murine Model of Sjögren's Syndrome.

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by severe inflammation of exocrine glands such as the salivary and lacrimal glands. When it affects the lacrimal glands, many patients experience keratoconjunctivitis due to severely dry eyes. This study investigated the pathological and immunological characteristics of ocular lesions in a mouse model of SS. Corneal epithelial injury and hyperplasia were confirmed pathologically. The number of conjunctival mucin-producing goblet cells was significantly decreased in the SS model mice compared with control mice. Expression levels of transforming growth factor (TGF)-ß, interleukin (IL)-6, tumor necrosis factor (TNF)-α, and C-X-C motif chemokine (CXCL) 12 were significantly higher in the corneal epithelium of the SS model mice than in control mice. Inflammatory lesions were observed in the Harderian, intraorbital, and extraorbital lacrimal glands in the SS model mice, suggesting that the ocular glands were targeted by an autoimmune response. The lacrimal glands of the SS model mice were infiltrated by cluster of differentiation (CD)4⁺ T cells. Real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed significantly increased mRNA expression of TNF-α, TGF-ß, CXCL9, and lysozyme in the extraorbital lacrimal glands of the SS model mice compared with control mice. These results add to the understanding of the complex pathogenesis of SS and may facilitate development of new therapeutic strategies.

Acceleration of tumor growth due to dysfunction in M1 macrophages and enhanced angiogenesis in an animal model of autoimmune disease.

Both autoimmunity and tumor immunity are immune responses against self-tissues or cells. However, the precise similarity or difference between them remains unclear. In this study, to understand a novel mechanism of tumor immunity, we performed transplantation experiments with a murine autoimmune model, C57BL/6J (B6)/lpr mice. A melanoma cell line, B16F10 cells, or granulocyte macrophage colony-stimulating factor- overexpressing B16F10 (B16F10/mGM) cells were transplanted into B6 or B6/lpr mice. Tumor growth by transplanted B16F10/mGM cells was significantly accelerated in B6/lpr mice compared with that in B6 mice. The accumulation of M1 macrophages in the tumor tissues of B6/lpr recipient mice was significantly lower compared with that in the control mice. In vitro co-culture experiment showed that impaired differentiation into M1 macrophages was observed in B6/lpr mice. The number of tumor vessels and vascular endothelial growth factor (VEGF) expression were also significantly enhanced in the tumor tissues of B6/lpr mice compared with those in the B6 mice. Moreover, VEGF expression was correlated with the increased expression of hypoxia-inducible factor-1α in the tumor tissues of B6/lpr mice. These results suggest that dysfunctional tumor immunity and enhanced angiogenesis in autoimmunity influence tumor growth.

Human odontogenic epithelial cells derived from epithelial rests of Malassez possess stem cell properties.

Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of the Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. ERM cells are unique epithelial cells that remain in periodontal tissues throughout adult life. They have a functional role in the repair/regeneration of cement or enamel. Here, we isolated odontogenic epithelial cells from ERM in the periodontal ligament, and the cells were spontaneously immortalized. Immortalized odontogenic epithelial (iOdE) cells had the ability to form spheroids and expressed stem cell-related genes. Interestingly, iOdE cells underwent osteogenic differentiation, as demonstrated by the mineralization activity in vitro in mineralization-inducing media and formation of calcification foci in iOdE cells transplanted into immunocompromised mice. These findings suggest that a cell population with features similar to stem cells exists in ERM and that this cell population has a differentiation capacity for producing calcifications in a particular microenvironment. In summary, iOdE cells will provide a convenient cell source for tissue engineering and experimental models to investigate tooth growth, differentiation, and tumorigenesis.

Impaired expansion of regulatory T cells in a neonatal thymectomy-induced autoimmune mouse model.

Neonatal thymectomy in certain mouse strains is known to induce organ-specific autoimmunity due to impaired functions of T cells, including Foxp3(+) regulatory T (Treg) cells in the thymus. The precise mechanism underlying the induction of autoimmunity by neonatal thymectomy remains unclear. One possibility is that depletion of Treg cells breaks down peripheral tolerance. We examined the functions of Treg cells by using a murine Sjögren syndrome model of NFS/sld mice that underwent neonatal thymectomy. The ratio of Treg cells to effector memory phenotype T cells in thymectomy mice was significantly lower than that of nonthymectomy mice. In addition, in vitro induction of peripherally induced Treg cells by transforming growth factor-ß (TGF-ß) using naive T cells from Sjögren syndrome model mice was severely impaired. The mRNA expression of TGF-ß receptor I and II and Smad3 and -4 in the TGF-ß-induced signal transduction pathway of Treg cells in this Sjögren syndrome model were lower than those of control mice. In addition, Treg cells in this Sjögren syndrome model exhibited an interferon-γ-producing Th1-like phenotype that resembled effector T cells. In conclusion, these results suggest that abnormal expansion and differentiation of Treg cells and inflammatory cytokines produced by Treg cells contribute to the development of autoimmunity.

Aromatase controls Sjögren syndrome-like lesions through monocyte chemotactic protein-1 in target organ and adipose tissue-associated macrophages.

Several autoimmune diseases are known to develop in postmenopausal women. However, the mechanism by which estrogen deficiency influences autoimmunity is unknown. Aromatase is an enzyme that converts androgens to estrogens. Herein, we used female aromatase gene knockout (ArKO) mice as a model of estrogen deficiency to investigate the molecular mechanism that underlies the onset and development of autoimmunity. Histological analyses showed that inflammatory lesions in the lacrimal and salivary glands of ArKO mice increased with age. Adoptive transfer of spleen cells or bone marrow cells from ArKO mice into recombination activating gene 2 knockout mice failed to induce the autoimmune lesions. Expression of mRNA encoding proinflammatory cytokines and monocyte chemotactic protein-1 increased in white adipose tissue of ArKO mice and was significantly higher than that in wild-type mice. Moreover, an increased number of inflammatory M1 macrophages was observed in white adipose tissue of ArKO mice. A significantly increased monocyte chemotactic protein-1 mRNA expression of the salivary gland tissue in ArKO was found together with adiposity. Furthermore, the autoimmune lesions in a murine model of Sjögren syndrome were exacerbated by administration of an aromatase inhibitor. These results suggest that aromatase may play a key role in the pathogenesis of Sjögren syndrome-like lesions by controlling the target organ and adipose tissue-associated macrophage.

A critical role for thymic stromal lymphopoietin in nickel-induced allergy in mice.

Ni is the most frequent cause of contact allergy induced by metals. However, the underlying mechanism of this induction is unknown. Our previous research demonstrates that activation of dendritic cells (DCs) through p38MAPK/MKK6 is required for Ni-induced allergy in mice. In the current study, we investigated the cellular and molecular mechanisms underlying Ni-induced allergy using a mouse model that involves injecting Ni into the ear, with or without Freund's incomplete or complete adjuvants. Nickel had greater potential to cause allergic reactions compared with palladium and gold. Among the proteins expressed at higher levels in mice with Ni-induced allergy, we focused on thymic stromal lymphopoietin (TSLP), which is produced in abundance by keratinocytes. We detected increased expression of the TSLP receptor (TSLPR) in DCs from cervical lymph nodes of mice with Ni-induced allergy, suggesting that DCs in ear tissues were activated through TSLPR signaling induced by keratinocyte-derived TSLP. Furthermore, delayed-type hypersensitivity reactions in mice with Ni-induced allergy were decreased significantly by injection of a Tslp-short interfering RNA along with atelocollagen in the ear skin. These results suggest that Ni allergy may be triggered by a TSLP/TSLPR-mediated interaction between epithelial and immune cells.

Molecular Mechanisms of Nickel Allergy.

Allergic contact hypersensitivity to metals is a delayed-type allergy. Although various metals are known to produce an allergic reaction, nickel is the most frequent cause of metal allergy. Researchers have attempted to elucidate the mechanisms of metal allergy using animal models and human patients. Here, the immunological and molecular mechanisms of metal allergy are described based on the findings of previous studies, including those that were recently published. In addition, the adsorption and excretion of various metals, in particular nickel, is discussed to further understand the pathogenesis of metal allergy.

Gimap3 and Gimap5 cooperate to maintain T-cell numbers in the mouse.

Gimap3 (IAN4) and Gimap5 (IAN5) are highly homologous GTP-binding proteins of the Gimap family. Gimap3 and Gimap5, whose transcripts are abundant in mature lymphocytes, can associate with antiapoptotic Bcl-2 family proteins. While it is established that Gimap5 regulates T-cell survival, the in vivo role of Gimap3 is unclear. Here we report the preparation and characteristics of mouse strains lacking Gimap3 and/or Gimap5. We found that the number of T cells was markedly reduced in mice deficient in both Gimap3 and Gimap5. The defects in T-cell cellularity were more severe in mice lacking both Gimap3 and Gimap5 than in mice lacking only Gimap5. No defects in the cellularity of T cells were detected in mice lacking only Gimap3, whereas bone marrow cells from Gimap3-deficient mice showed reduced T-cell production in a competitive hematopoietic environment. Moreover, retroviral overexpression and short hairpin RNAs-mediated silencing of Gimap3 in bone marrow cells elevated and reduced, respectively, the number of T cells produced in irradiated mice. These results suggest that Gimap3 is a regulator of T-cell numbers in the mouse and that multiple Gimap family proteins cooperate to maintain T-cell survival.

Mechanism of activation-induced cell death of T cells and regulation of FasL expression.

Activation-induced cell death (AICD) of T cells is a process for regulating the peripheral immune system. The fate of a T cell is controlled by numerous signals derived from various stimuli, such as antigens, cytokines, and chemokines. In healthy humans, overactivated or autoreactive T cells are harmful and are eliminated to maintain the immune system. AICD in T cells by Fas/FasL-mediated apoptosis is triggered by the switch from life to death through several signaling molecules. The control or distribution of Fas or FasL expression largely affects AICD of T cells. Although autoimmune diseases are considered to be induced by multiple factors, an impaired immune system with AICD by Fas/FasL-mediated apoptosis leads to the onset or development of autoimmunity. Based on published reports, this review describes the regulatory mechanisms involved in AICD of T cells by Fas/ FasL-mediated apoptosis and the associations between AICD and autoimmunity in humans and animal models.