Immunosuppressive therapy and humoral response to third mRNA COVID-19 vaccination with a six-month interval in rheumatic disease patients.

OBJECTIVES: To evaluate the long-term impact of immunosuppressive therapeutic agents on antibody response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mRNA vaccination in patients with autoimmune rheumatic diseases (AIRD) in order to propose a strategy for annual vaccination. METHODS: This prospective multicentre cohort study evaluated the humoral response to second and third BNT162b2 and/or mRNA-1273 vaccines in 382 Japanese AIRD patients classified into 12 different medication groups and in 326 healthy controls (HCs). The third vaccination was administered six months after the second vaccination. Antibody titres were measured using the Elecsys Anti-SARS-CoV-2 S assay. RESULTS: The seroconversion rate and antibody titres were lower in AIRD patients than in HCs 3-6 weeks after the second vaccination and 3-6 weeks after the third vaccination. Seroconversion rates were <90% after the third vaccination in patients receiving mycophenolate mofetil and rituximab. Antibody levels after the third vaccination were significantly lower in the groups prescribed TNF inhibitor with or without methotrexate, abatacept and rituximab or cyclophosphamide than those of HCs in a multivariate analysis adjusting for age, sex, and glucocorticoid dosage. The third vaccination induced an adequate humoral response in patients treated with sulfasalazine, bucillamine, methotrexate monotherapy, iguratimod, interleukin-6 inhibitors or calcineurin inhibitors including tacrolimus. CONCLUSIONS: Repeated vaccinations in many immunosuppressed patients produced antibody responses similar to those observed in HCs. In contrast, annual vaccination in patients receiving TNF inhibitors, abatacept, mycophenolate mofetil and rituximab may require caution.

TNFR2 Signaling Enhances Suppressive Abilities of Human Circulating T Follicular Regulatory Cells.

T follicular regulatory (Tfr) cells are a subset of CD4+ T cells that express CXCR5 and migrate into germinal centers (GCs). They regulate GC reactions by communicating with T follicular helper (Tfh) and B cells. TNF inhibitors are used in inflammatory diseases; however, the generation of autoantibodies or anti-drug Abs sometimes causes problems. Because TNFR2 signaling is important for suppressive functions of regulatory T cells, we investigated the role of TNFR2 on human Tfr cells. Tfr cells stimulated with MR2-1 (an anti-TNFR2 agonistic Ab) were analyzed for cell proliferation, Foxp3 expression, and surface molecules. Tfh/B cell proliferation, IgM production, and differentiation in cocultures with MR2-1-stimulated Tfr cells were examined. Tfr cells express a high level of TNFR2. MR2-1 stimulation altered the gene expression profile of Tfr cells. Cell proliferation and Foxp3 expression of Tfr cells were enhanced by MR2-1. MR2-1-stimulated Tfr cells expressed ICOS and Programmed cell death protein 1 and significantly suppressed Tfh/B cell proliferation, IgM production, and B cell differentiation. TNFR2-stimulated Tfr cells retained the migration function according to the CXCL13 gradient. In conclusion, we showed that TNFR2-stiumulated Tfr cells can regulate Tfh and B cells. Aberrant antibody production during TNF inhibitor treatment might be, at least in part, associated with TNFR2 signaling inhibition in Tfr cells. In addition, expansion and maturation of Tfr cells via TNFR2 stimulation in vitro may be useful for a cell-based therapy in inflammatory and autoimmune diseases to control GC reactions.

No clear influence of treatment escalation on flare prevention in serologically active clinically quiescent patients with systemic lupus erythematosus: a retrospective cohort study.

This study aimed to clarify the efficacy and safety of treatment escalation by initiating therapeutic agents in serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE). We retrospectively evaluated SACQ patients with SLE for ≥ 180 days, with the introduction of a therapeutic agent for SLE defined as exposure. The efficacy endpoints included the time to flare and time to remission, whereas the safety endpoint was the incidence of adverse events. The efficacy endpoints were assessed via Cox proportional hazards model with time-dependent covariates, which included exposure, serological activity, and prednisolone dose. Among 109 SACQ patients, 24 were initiated on the following therapeutic agents for SLE: hydroxychloroquine (10 patients), belimumab (6 patients), and immunosuppressive agents (8 patients). A total of 37 patients experienced a flare (8 and 29 patients during exposure and nonexposure periods, respectively). The time to flare was comparable between the exposure and control groups. Among 68 patients who were not in remission at the start of observation, 27 patients achieved remission (5 and 22 patients during exposure and nonexposure periods, respectively). Although both groups had a similar time to remission, the exposure group treated with belimumab had a significantly higher rate of remission than the control group. The adverse events were more frequent during the exposure period than during the nonexposure period. Thus, this study did not reveal a clear influence of treatment escalation on flare prevention and remission achievement.

Influences of advanced age in rheumatoid arthritis: A multicentre ultrasonography cohort study.

OBJECTIVES: We aimed to evaluate the effects of age on clinical characteristics and outcomes in biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD)-naïve patients with rheumatoid arthritis (RA). METHODS: We analysed the cases of 234 Japanese b/tsDMARD-naïve RA patients who underwent b/tsDMARD treatment in a multicentre ultrasound prospective observational cohort. We compared the clinical characteristics at baseline and outcomes at 12 months between those aged ≥60 years and those <60 years. RESULTS: Compared to the <60-year-old group (n = 78), the ≥60-year-old group (n = 156) had higher inflammatory marker values and ultrasound combined scores, especially wrist joints, at baseline. Age at baseline positively correlated significantly with the ultrasound scores at baseline; however, age was not a significant variable by the multiple regression analysis. The patients treated with different MOAs in the ≥60-year-old group had comparable outcomes and multiple regression analysis revealed that mechanism of action (MOA) was not a significant contributor to the Clinical Disease Activity Index at 12 months. CONCLUSIONS: RA patients with advanced age demonstrated distinctive clinical characteristics. The MOAs were not associated with clinical outcomes and ultrasound outcomes in RA patients with advanced age.

Anti-dsDNA IgE induces IL-4 production from basophils, potentially involved in B-cell differentiation in systemic lupus erythematosus.

OBJECTIVES: Recently, the involvement of basophils and IgE-type autoantibodies in the pathogenesis of SLE has been elucidated using mouse models; however, few studies have been conducted in humans. In this study, the role of basophils and anti-double-stranded DNA (dsDNA) IgE in SLE was examined using human samples. METHODS: The correlation between disease activity and serum levels of anti-dsDNA IgE in SLE was evaluated using enzyme-linked immunosorbent assay. Cytokines produced by IgE-stimulated basophils from healthy subjects were assessed using RNA sequences. The interaction of basophils and B cells to promote B cell differentiation was investigated using a co-culture system. The ability of basophils from patients with SLE with anti-dsDNA IgE to create cytokines that may be involved in B cell differentiation in response to dsDNA was examined using real-time PCR. RESULTS: Anti-dsDNA IgE levels in the serum of patients with SLE correlated with disease activity. Healthy donor basophils produced IL-3, IL-4 and TGF-ß1 after anti-IgE stimulation. Co-culture of B cells with anti-IgE-stimulated basophils increased plasmablasts which were cancelled by neutralizing IL-4. After encountering the antigen, basophils released IL-4 more quickly than follicular helper T cells. Basophils isolated from patients with anti-dsDNA IgE promoted IL-4 expression by adding dsDNA. CONCLUSIONS: These results suggest that basophils contribute to the pathogenesis of SLE by promoting B cell differentiation via dsDNA-specific IgE in patients similar to the process described in mouse models.

Safety and efficacy of switching immunosuppressive drugs for maintenance treatment in patients with systemic lupus erythematosus: A retrospective cohort study.

OBJECTIVES: We aim to clarify the efficacy and safety of switching immunosuppressive drugs and to identify the predictive factors for treatment failure after switching in patients with systemic lupus erythematosus (SLE). METHODS: We retrospectively evaluated patients with SLE who switched immunosuppressive drugs for any reason in our hospital between 2015 and 2020. The efficacy endpoints were the change in SLE Disease Activity Index 2000 score, prednisolone dose, and disease status over 12 months, as well as treatment continuation rates. The safety endpoint was the frequency of adverse events over 1 year before and after switching. Cox hazard regression analyses were used to identify the predictive factors for treatment failure. RESULTS: Thirty-nine patients (age, 41.5 ± 12.6 years; 35 women and 4 men) were analysed. The SLE Disease Activity Index score and prednisolone dose were significantly reduced after switching, with few disease exacerbations over 12 months. The 1- and 2-year continuation rates were 71.4% and 62.3%, respectively. The frequency of adverse events was similar in the year before and after switching the drug. Drug switching due to inadequate efficacy was a predictive factor of less likely treatment failure. CONCLUSIONS: Immunosuppressive drug switching led to reduced disease activity and decreased glucocorticoid dose without disease exacerbations and severe adverse events.

Antibody response to SARS-CoV-2 mRNA vaccines in patients with rheumatic diseases in Japan: Interim analysis of a multicentre cohort study.

OBJECTIVES: To evaluate the impact of medication on antibody response to severe acute respiratory syndrome coronavirus-2 mRNA vaccines in Japanese patients with rheumatic diseases. METHODS: This prospective multicentre cohort study evaluated the humoral response in 12 different medication groups. Antibody levels before the first vaccination and 3-6 weeks after the second vaccination were measured using the Elecsys Anti-SARS-CoV-2 S assay. Statistical analysis included comparing antibody titres among the different medication groups using the Kruskal-Wallis test followed by the Bonferroni-Dunn test and multiple linear regression analysis. RESULTS: 295 patients were analysed. The seroconversion rate was 92.2% and the median antibody titre was 255 U/ml (interquartile range, 34.1-685) after the second mRNA vaccination. Antibody levels were significantly lower in the groups treated with Tumour necrosis factor inhibitor with methotrexate, abatacept, mycophenolate mofetil (MMF), MMF or mizoribine combined with calcineurin inhibitor, and rituximab or cyclophosphamide compared with those treated with sulfasalazine and/or bucillamine or calcineurin inhibitor (p < 0.01). The correlation between antibody titre and treatment was significant after adjusting for age, gender, and glucocorticoid dose (p < 0.01). CONCLUSIONS: Additional early vaccination is required in patients treated with Tumour necrosis factor inhibitor and methotrexate, abatacept, MMF, MMF or mizoribine combined with calcineurin inhibitor and rituximab or cyclophosphamide.

Activation of caspase-1 is mediated by stimulation of interferon genes and NLR family pyrin domain containing 3 in monocytes of active systemic lupus erythematosus.

OBJECTIVES: Emerging evidence has shown the importance of inflammasome activation in the progression of autoimmune diseases. In this study, we aimed to identify the main cell types activating inflammasome in autoimmune diseases and to clarify the intracellular pathway of inflammasome activation in systemic lupus erythematosus (SLE). METHODS: Active caspase-1 in each subset of human peripheral blood cells from healthy controls (n=18), SLE (n=51), and other rheumatic diseases (n=36) were fluorescently probed with FLICA™-caspase-1 followed by flow cytometric analysis. The correlation of caspase-1 activation in monocytes and clinical parameters in SLE patients were evaluated. In-vitro experiments were performed to identify the pathway involved in caspase-1 activation induced by SLE serum in monocytes. RESULTS: Active caspase-1 in monocytes was upregulated in SLE patients. Cluster of differentiation 14 (CD14)-positive and CD16-positive monocytes showed considerable activation of caspase-1 compared with the other subsets of monocytes. Serum titres of anti-double stranded DNA antibodies were positively correlated with active caspase-1 in monocytes, and serum complement component 3 and platelet count were negatively correlated with active caspase-1 in monocytes. The SLE serum-induced activation of caspase-1 and IL-1ß secretion were down-regulated by inhibition of NLR family pyrin domain containing 3 (NLRP3), cyclic GMP-AMP synthase (cGAS), or stimulator of interferon genes (STING). CONCLUSIONS: These findings suggest that targeting inflammasome by regulating cGAS/STING and NLRP3 are potential therapeutic strategies for SLE.

Homeostatic Milieu Induces Production of Deoxyribonuclease 1-like 3 from Myeloid Cells.

DNase 1-like 3 (DNase1L3), which belongs to DNase1 family, was originally identified as one of apoptosis- and necrosis-related endonucleases that fragmentate intranucleosomal DNA. A loss-of-function mutation has been reported in murine models of systemic lupus erythematosus (SLE) and in familial SLE patients. These reports suggest DNase1L3 plays an important role in the prevention of developing SLE; however, expression and function of DNase1L3 in human immune systems have been largely unclarified. As previous reports showed DNase1L3 is expressed in hematopoietic organs, we first analyzed expression levels of DNase1L3 in each subset of human peripheral blood cells by quantitative real-time PCR. Plasmacytoid dendritic cells showed the highest expression levels of DNase1L3 mRNA among peripheral blood cells. IL-4 enhanced DNase1L3 expression in monocytes, monocyte-derived dendritic cells, and monocyte-derived macrophages (MDMs), but not in T cells, B cells, or plasmacytoid dendritic cells. Together with IL-4, all-trans retinoic acid and apoptotic cells efficiently upregulated expression of DNalse1L3 in MDMs. As a result of intracellular signaling analysis, Jak1-IRS2-ERK/PI3K pathway was essential for IL-4-induced DNase1L3 expression. IL-4-treated monocyte-derived dendritic cells and MDMs secreted active DNase1L3 protein that could degrade liposome-DNA complexes, which were resistant to DNase1. Our results indicate DNase1L3 is secreted by innate immune cells and may play a critical role in the tissue homeostasis and on prevention of developing autoimmunity by degrading self-DNA.

Hydroxychloroquine versus tacrolimus for the treatment of persistently active systemic lupus erythematosus.

OBJECTIVES: We aimed to reveal the effectiveness of hydroxychloroquine (HCQ) compared with tacrolimus (TAC), an immunosuppressive agent, in patients with systemic lupus erythematosus (SLE) with persistent activity on standard treatment. METHODS: We retrospectively compared the efficacy and safety of the treatment between 18 patients receiving HCQ and 27 patients receiving TAC. None of the patients were in the lupus low disease activity state (LLDAS) at the beginning of this study. The efficacy end points were the cumulative incidence of LLDAS attainment without additional immunosuppressive agents, drug continuation rate, and treatment failure-free survival. The safety end point was the frequency of adverse events. RESULTS: Eight (44.4%) patients in the HCQ group and 10 (37.0%) patients in the TAC group achieved LLDAS during the follow-up period; thus, the cumulative incidences of LLDAS attainment of the two treatments were nearly identical. The drug continuation and treatment failure-free survival rates were also not different between the two groups. The frequency of adverse events showed no clear differences between the two groups. CONCLUSIONS: The efficacy and safety of an add-on treatment with HCQ are similar to those with TAC. Patients with persistently active SLE can benefit from HCQ in efforts to achieve at least low disease activity.

Type 1 helper T cells generate CXCL9/10-producing T-bet+ effector B cells potentially involved in the pathogenesis of rheumatoid arthritis.

Efficacy of B-cell depletion therapy highlights the antibody-independent effector functions of B cells in rheumatoid arthritis (RA). Given type 1 helper T (Th1) cells abundant in synovial fluid (SF) of RA, we have determined whether Th1 cells could generate novel effector B cells. Microarray and qPCR analysis identified CXCL9/10 transcripts as highly expressed genes upon BCR/CD40/IFN-γ stimulation. Activated Th1 cells promoted the generation of CXCL9/10-producing T-bet+ B cells. Expression of CXCL9/10 was most pronounced in CXCR3+ switched memory B cells. Compared with peripheral blood, SFRA enriched highly activated Th1 cells that coexisted with abundant CXCL9/10-producing T-bet+ B cells. Intriguingly, anti-IFN-γ antibody and JAK inhibitors significantly abrogated the generation of CXCL9/10-producing T-bet+ B cells. B cell derived CXCL9/10 significantly facilitated the migration of CD4+ T cells. These findings suggest that Th1 cells generate the novel CXCL9/10-producing T-bet+ effector B cells that could be an ideal pathogenic B cell target for RA therapy.

Predictive factors of fetal and maternal pregnancy outcomes in Japanese patients with systemic lupus erythematosus.

OBJECTIVE: The number of pregnant and delivery cases in systemic lupus erythematosus (SLE) patients are increasing due to the advances in therapies. However, there are many problems such as the exacerbation of SLE during pregnancy and the risk of fetal complications. We investigated the impact of both pregnancy on lupus and lupus on pregnancy in Japanese patients. METHODS: We retrospectively analyzed 64 pregnancies in 39 cases of lupus patients at Kyushu University Hospital, Japan, from October 2002 to July 2018 and then assessed the clinical profiles and maternal and fetal outcomes. RESULTS: In terms of the impact of pregnancy on SLE, 29.7% of patients had lupus flare during pregnancy. Multivariate analysis showed that flare rates were significantly higher in patients who discontinued the immunosuppressants when pregnancy was detected or before pregnancy. Pregnancy results were 25.0% for preterm birth, 39.1% for low birth weight infants, and 31.3% for small-for-gestational-age infants. Regarding the effect of SLE on fetal death, the rates of stillbirth were significantly higher in cases whose C3 value at 12 weeks of gestation was lower than before conception. Preterm birth was associated with disease duration and lupus flare during pregnancy. CONCLUSIONS: Discontinuation of immunosuppressive drugs was a predictive factor for lupus flare during pregnancy. Further, the decrease of C3 levels at 12 weeks of gestation from baseline was a predictive factor for fetal loss. It is essential for lupus pregnant patients to prevent flares, even with the use of immunosuppressive medications.

Association of circulating SLAMF7+Tfh1 cells with IgG4 levels in patients with IgG4-related disease.

BACKGROUND: Follicular helper CD4+ T (Tfh) cells have a critical role in IgG4 production by B cells in IgG4-related disease (IgG4-RD). Recent studies including ours showed that SLAMF7+CD4+ T cells are an important pathological driver of IgG4-RD. In this study, we have sought to elucidate a relationship between helper CD4+ T (Th), particularly Tfh, cells and SLAMF7+ CD4+ T cells in IgG4-RD. RESULTS: The patients with IgG4-RD enrolled in this study were aged 66 ± 12 years and their titers of serum IgG4 were 372 ± 336 mg/dl. Th1 cells, activated circulating Tfh1 (cTfh1), and activated cTfh2 cells increased in IgG4-RD. SLAMF7 was mainly expressed on Th1 and cTfh1, but not cTfh2, cells in the patients. SLAMF7+ cTfh1 cells were PD-1/CD28 double-positive, whereas SLAMF7+ Th1 cells were CD28 negative. Positive correlations were noted between serum IgG4 levels and the number of activated cTfh2 cells and SLAMF7+ cTfh1 cells, but not SLAMF7+ Th1 cells. Intriguingly, among cTfh1 cells, activated SLAMF7+ cTfh1 cells were high producers of IL-10 along with IL-21. Blimp-1, but not Bcl-6, mRNA was expressed at high levels in activated SLAMF7+ cTfh1 cells. In addition to CD4+ T cells, the frequency of SLAMF7+ fraction was higher in memory B cells than naïve B cells in patients with IgG4RD. Finally, upon stimulation via B-cell receptor and CD40, Tfh1-associated cytokines, IL-21 and IFN-γ, most significantly induced SLAMF7 expression in memory B cells. CONCLUSIONS: Together, these results suggest that circulating SLAMF7+ Tfh1 cells, along with Tfh2 cells, play a pathologic role in IgG4 production in IgG4-RD.

Shoulder ultrasound and serum lactate dehydrogenase predict inadequate response to glucocorticoid treatment in patients with polymyalgia rheumatica.

We aimed to identify predictors of inadequate response to glucocorticoid (GC) treatment in patients with polymyalgia rheumatica (PMR). We retrospectively studied 32 patients as a derivation cohort and 24 patients as a validation cohort. The patients were divided into two groups according to the response to GC treatment: GC-responders and GC-inadequate responders (GC-IRs). We compared laboratory data and bilateral shoulder ultrasound findings between the groups. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff value of candidate predictors of treatment response; the predictors were examined using multivariate logistic analysis. Gray-scale ultrasound findings of long head of the biceps (LHB) tenosynovitis and subacromial/subdeltoid (SAD) bursitis were scored semiquantitatively (0-3). A total gray-scale score (TGSS) was calculated as the sum of the gray-scale scores. In the derivation cohort, serum lactate dehydrogenase (LDH) levels and TGSS were significantly higher in GC-IRs than in GC-responders. On ROC analysis, the cutoff values of serum LDH levels ≥ 175 IU/ml and TGSS ≥ 5 were found to be the candidate predictors. Multivariate logistic analysis revealed an independent association of both the predictors with inadequate response to GC treatment. In the validation cohort, patients with one or both predictors exhibited a higher incidence of inadequate response to GC treatment. These findings indicate that the severities of LHB tenosynovitis and SAD bursitis evaluated using ultrasound and serum LDH levels are independent predictors of inadequate response to GC treatment in patients with PMR. Treatment adjustment based on prediction model may allow precise treatment of patients with PMR.

Identification of unipotent megakaryocyte progenitors in human hematopoiesis.

The developmental pathway for human megakaryocytes remains unclear, and the definition of pure unipotent megakaryocyte progenitor is still controversial. Using single-cell transcriptome analysis, we have identified a cluster of cells within immature hematopoietic stem- and progenitor-cell populations that specifically expresses genes related to the megakaryocyte lineage. We used CD41 as a positive marker to identify these cells within the CD34+CD38+IL-3RαdimCD45RA- common myeloid progenitor (CMP) population. These cells lacked erythroid and granulocyte-macrophage potential but exhibited robust differentiation into the megakaryocyte lineage at a high frequency, both in vivo and in vitro. The efficiency and expansion potential of these cells exceeded those of conventional bipotent megakaryocyte/erythrocyte progenitors. Accordingly, the CD41+ CMP was defined as a unipotent megakaryocyte progenitor (MegP) that is likely to represent the major pathway for human megakaryopoiesis, independent of canonical megakaryocyte-erythroid lineage bifurcation. In the bone marrow of patients with essential thrombocythemia, the MegP population was significantly expanded in the context of a high burden of Janus kinase 2 mutations. Thus, the prospectively isolatable and functionally homogeneous human MegP will be useful for the elucidation of the mechanisms underlying normal and malignant human hematopoiesis.

Are the 2016 EULAR/ACR/PRINTO classification criteria for macrophage activation syndrome applicable to patients with adult-onset Still's disease?

The objectives of this study are to determine whether the 2016 European League Against Rheumatism/American College of Rheumatology/Paediatric Rheumatology International Trials Organization classification criteria for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (SJIA) can be used to identify MAS in patients with adult-onset Still's disease (AOSD). Using laboratory data from 76 AOSD patients with and without MAS, we analyzed the ability of the collective and individual constitutive elements of the 2016 MAS in SJIA criteria and additional laboratory measures to discriminate between AOSD patients with (n = 16) and without (n = 60) MAS. Cutoff values to determine the sensitivity, specificity, and predictive values were calculated from receiver operating characteristic curves, and modified classification criteria for MAS in AOSD were evaluated. The 2016 MAS in SJIA classification criteria had an overall sensitivity of 100%, specificity of 70.0%, positive predictive value of 47.1%, and negative predictive value of 100% to discriminate between AOSD patients with and without MAS based on laboratory data. Among the individual criteria, the sensitivity of triglycerides (46.7%) and the specificity of ferritin (15.0%) for MAS in AOSD were particularly low. The sensitivity and specificity for classifying MAS in AOSD patients were increased to 100 and 93%, respectively, by excluding triglycerides and changing the cutoff values for other criteria in the 2016 MAS in SJIA classification. The 2016 classification criteria for MAS in SJIA had higher sensitivity but lower specificity to identify MAS in AOSD patients compared with SJIA patients.

Functional interleukin-33 receptors are expressed in early progenitor stages of allergy-related granulocytes.

Interleukin-33 (IL-33) induces T helper type 2 (Th2) cytokine production and eosinophilia independently of acquired immunity, leading to innate immunity-mediated allergic inflammation. Allergy-related innate myeloid cells such as eosinophils, basophils and mast cells express the IL-33 receptor (IL-33R), but it is still unknown how IL-33 regulates allergic inflammation involving these cells and their progenitors. Here, we revealed that the functional IL-33R was expressed on eosinophil progenitors (EoPs), basophil progenitors (BaPs) and mast cell progenitors (MCPs). In the presence of IL-33, these progenitors did not expand, but produced a high amount of Th2 and pro-inflammatory cytokines such as IL-9, IL-13, IL-1ß and IL-6. The amount of cytokines produced by these progenitors was greater than that by mature cells. In vivo, IL-33 stimulated the expansion of EoPs, but it was dependent upon the elevated serum IL-5 that is presumably derived from type 2 innate lymphoid cells that express functional IL-33R. These data collectively suggest that EoPs, BaPs and MCPs are not only the sources of allergy-related granulocytes, but can also be sources of allergy-related cytokines in IL-33-induced inflammation. Because such progenitors can differentiate into mature granulocytes at the site of inflammation, they are potential therapeutic targets in IL-33-related allergic diseases.

Increased CD226 Expression on CD8+ T Cells Is Associated with Upregulated Cytokine Production and Endothelial Cell Injury in Patients with Systemic Sclerosis.

Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular damage and fibrosis of the skin and internal organs. Because activated and oligoclonally expanded CD8(+) T cells can be detected in peripheral blood and lungs of SSc patients, effector memory CD8(+) T cells may play a critical role for organ involvement in SSc; however, the pathogenic functions of effector memory CD8(+) T cells remain incompletely understood. In this study, we performed DNA microarray analysis of the sort-purified effector memory CD8(+) T cells from SSc patients and healthy controls, and showed that the expression of genes related to immune response and cell adhesion, including CD226 (also known as DNAX accessory molecule-1 [DNAM-1]), was significantly altered. Moreover, detailed analysis of CD226 revealed that CD226(high)CD8(+) T cells were increased in SSc patients (mean, 50.7%) compared with healthy controls (32.9%) and were appreciably associated with the severity of skin sclerosis and interstitial lung disease. Furthermore, CD226(+)CD8(+) T cells produced higher amount of various cytokines than CD226(-) ones, and CD226(high)CD8(+) T cells from SSc patients showed upregulated IL-13 production and positive correlation with the cytotoxic capacity of CD8(+) T cells against HUVECs. Finally, the neutralization of CD226 in CD8(+) T cells impaired costimulation, cytokine productions, and cytolysis against HUVECs. These findings indicate that upregulated CD226 expression on CD8(+) T cells reflects disease severity and is involved in SSc pathogenesis via the production of various cytokines, including profibrotic IL-13 and endothelial cell injury, and that CD226 may be a useful target in the treatment of SSc.

CD41 marks the initial myelo-erythroid lineage specification in adult mouse hematopoiesis: redefinition of murine common myeloid progenitor.

Previous studies have predicted that reciprocal activation of GATA-1 and PU.1 regulates myelo-erythroid versus myelo-lymphoid lineage commitment in early hematopoiesis. Such PU.1-activating myelo-lymphoid progenitors exist within the lymphoid-primed multipotent progenitor (LMPP) population at the primitive Lineage(-) Sca-1(+) c-Kit(+) (LSK) stage. We here show that the counterpart of GATA-1-activating myelo-erythroid progenitor resides also at the LSK stage, expressing CD41 at a high level. Purified CD41(hi) LSK cells showed exceedingly strong and prolonged myelo-erythroid-restricted reconstitution, and primed myelo-erythroid gene expression with a more primitive molecular signature as compared to the original common myeloid progenitor (CMP). The CD41(hi) LSK cells more strongly contributed to emergent and malignant myelopoiesis than LMPPs, and produced the original CMP by downregulating Sca-1 and CD41, suggesting that they are the earliest CMPs. Thus, the hematopoietic developmental map should be revised by integrating the primary branchpoint comprised of the new, isolatable CD41(hi) CMP and the LMPP populations.

A case of marginal zone B cell lymphoma mimicking IgG4-related dacryoadenitis and sialoadenitis.

BACKGROUND: IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS), so-called Mikulicz's disease, is characterized by elevated serum IgG4 and infiltration of IgG4-positive plasma cells in glandular tissues. Recently, several studies reported both malignant lymphoma developed on the background of IgG4-associated conditions and IgG4-producing malignant lymphoma (non-IgG4-related disease). CASE PRESENTATION: We report on the case of a 70-year-old man who was strongly suspected IgG4-DS because of high serum IgG4 concentration (215 mg/dl) and bilateral swelling of parotid and submandibular glands. Biopsies of cervical lymph node and a portion of submandibular gland were performed. These histopathological findings subsequently confirmed a diagnosis of marginal zone B cell lymphoma. CONCLUSION: Differential diagnosis of IgG4-DS is necessary from other disorders, including Sjögren's syndrome, sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, and cancer. We suggest that biopsy of swollen lesions is important for a definitive diagnosis of IgG4-DS and discuss the mechanism of development in this case.