Identification of lipophilic ligands of Siglec5 and -14 that modulate innate immune responses.

Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of cell-surface immune receptors that bind to sialic acid at terminal glycan residues. Siglecs also recognize nonsialic acid ligands, many of which remain to be characterized. Here, we found that Siglec5 and Siglec14 recognize lipid compounds produced by Trichophyton, a fungal genus containing several pathogenic species. Biochemical approaches revealed that the Siglec ligands are fungal alkanes and triacylglycerols, an unexpected finding that prompted us to search for endogenous lipid ligands of Siglecs. Siglec5 weakly recognized several endogenous lipids, but the mitochondrial lipid cardiolipin and the anti-inflammatory lipid 5-palmitic acid-hydroxystearic acid exhibited potent ligand activity on Siglec5. Further, the hydrophobic stretch in the Siglec5 N terminus region was found to be required for efficient recognition of these lipids. Notably, this hydrophobic stretch was dispensable for recognition of sialic acid. Siglec5 inhibited cell activation upon ligand binding, and accordingly, the lipophilic ligands suppressed interleukin-8 (IL-8) production in Siglec5-expressing human monocytic cells. Siglec14 and Siglec5 have high sequence identity in the extracellular region, and Siglec14 also recognized the endogenous lipids. However, unlike Siglec5, Siglec14 transduces activating signals upon ligand recognition. Indeed, the endogenous lipids induced IL-8 production in Siglec14-expressing human monocytic cells. These results indicated that Siglec5 and Siglec14 can recognize lipophilic ligands that thereby modulate innate immune responses. To our knowledge, this is the first study reporting the binding of Siglecs to lipid ligands, expanding our understanding of the biological function and importance of Siglecs in the innate immunity.

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.

Successful golimumab therapy in four patients with refractory Takayasu's arteritis.

Recent studies suggested that anti-TNF-α biological therapies are effective in treating Takayasu's arteritis (TA) refractory to conventional immunosuppressive therapy. However, the efficacy of golimumab (GLM) for TA therapy is unknown. We report four women with TA who were successfully treated with GLM. GLM was prescribed as induction therapy for three patients and as maintenance therapy for one patient. GLM showed therapeutic value and might be useful, together with other anti-TNF-α agents, in treating TA.

The balance between Foxp3 and Ror-γt expression in peripheral blood is altered by tocilizumab and abatacept in patients with rheumatoid arthritis.

BACKGROUND: The balance between Th17 cells and regulatory T (Treg) cells has been shown to play an important role in the development of rheumatoid arthritis (RA). Recent studies have shown that treatment with abatacept (ABT) or tocilizumab (TCZ) affects Th17 and Treg cell populations. Although not unanimously accepted, several reports have shown that Treg cells are decreased by ABT and increased by TCZ, and that Th17 cells are decreased by TCZ. To further investigate the effects of ABT and TCZ on the skewing of T cell populations, we analyzed the expression of master regulators genes of helper T cell lineages following ABT/TCZ treatment of RA patients. METHODS: Ten patients treated with ABT and 10 patients treated with TCZ were enrolled. Total RNA was extracted from peripheral blood cells at baseline, and after 12 and 24 weeks of therapy. The expression levels of T-bet, GATA3, Foxp3 and Ror-γt were semi-quantified using real-time PCR. The relative expression levels were expressed as the ratios of two genes (T-bet/GATA3, Foxp3/GATA3, Foxp3/T-bet, Foxp3/Ror-γt, Ror-γt/T-bet, Ror-γt/GATA3), and the changes in these ratios with treatment were determined. RESULTS: The Foxp3/Ror-γt ratio was decreased after ABT therapy (0.67 ± 0.16 at 24 weeks, P = 0.0034) but was increased after TCZ therapy (2.00 ± 1.03 at 24 weeks, P = 0.0013). In addition, the Ror-γt/GATA3 ratio was decreased after TCZ therapy (0.78 ± 0.37 at 24 weeks, P = 0.0008). Except for these ratios, no significant skewing in the expression of these factors was detected. No significant relationship between clinical response to the treatment and change in the ratios of these factors was determined. CONCLUSION: Treatment with TCZ or ABT differently affected the balance between Foxp3 and Ror-γt expression in the peripheral blood of patients with RA.

[Anesthetic management of a patient with diaphragmatic relaxation and megacolon].

We managed an 87-year-old man with diaphragmatic relaxation under general anesthesia. He had dyspnea and severe constipation. The chest X-ray revealed that two thirds of the left chest cavity were compressed by the megacolon gas. The Spo2 before the operation was 93%. The colon gas was deflated before and after the induction of anesthesia. There was no significant improvement in the tidal volume and the arterial oxygen tension. The postoperative chest X-ray showed that the shift of the left diaphragm was improved. He was able to walk 100 meters and the severe constipation disappeared after the operation.

[BCMA and autoantibody-producing RP105 B cells; possible new targets of B cell therapy in systemic lupus erythematosus].

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disease with multiple organ disorders. Although the prognosis of SLE has been recently improved, corticosteroid and immunosuppressive agents are still main treatment used in medical practice. Refractory disease and complications by the conventional drugs still remain. RP105 (CD180) is one of the toll-like receptor associated molecules. The molecule is expressed on mature B cells. Significantly increased population of RP105-negative [RP105(-)] B cells is found in SLE. RP105(-) B cells belong to highly activated and differentiated late B cells and produce autoantibodies including anti-dsDNA antibodies. RP105(-) B cells are further divided into at least 5 subsets that include novel human B cell subsets. In active SLE, subset 1 (activated B cells) and 3 (early-plasmablasts) are significantly increased compared to inactive SLE patients. Especially, subset 3 RP105(-) B cells may play an important role in pathophysiology of SLE. RP105(-) B cells from active SLE patients express preferentially BCMA (B-cell maturation antigen) compared to BAFF-R (B-cell activating factor-receptor) than normal subjects and other autoimmune diseases. In SLE, it is suggested that BAFF/APRIL (a proliferation-inducing ligand) maintain chronic activation and survival of RP105(-) B cells. The increased RP105(-) B cells may reflect the breaking of tolerance checkpoint for autoreactive B cells and finally affect autoimmunity in SLE. For the B cell therapy, especially targeting of autoantibody-producing B cells, including subset 3 of RP105(-) B cells, BCMA and RP105(-) B cell itself may be an ideal target.

Phenotyping of P105-negative B cell subsets in patients with systemic lupus erythematosus.

This study aimed to investigate phenotype of RP105(-) B cell subsets in patients with systemic lupus erythematosus (SLE). Flow cytometry was used for phenotyping RP105-negaive B cell subsets. Based on CD19, RP105, and CD138 expression, RP105(-) B cells consist of at least 5 subsets of late B cells, including CD19(+)RP105(int), CD19(+) RP105(-), CD19(low) RP105(-) CD138(-), CD19(low) RP105(-)CD138(int), and CD19(low) RP105(-) CD138(++) B cells. Especially, CD19(+)RP105(int) and CD19(low) RP105(-)CD138(int) B cells are significantly larger than other RP105(-) B cell subsets in SLE. By comparison of RP105(-) B cell subsets between patients with SLE and normal subjects, these subsets were detectable even in normal subjects, but the percentages of RP105(-) B cell subsets were significantly larger in SLE. The phenotypic analysis of RP105(-) B cell subsets suggests dysregulation of later B cell subsets in SLE and may provide new insights into understanding regulation of B cells in human SLE.

Therapeutic response of patients with adult Still's disease to biologic agents: multicenter results in Japan.

OBJECTIVE: The efficacy of biologics in treating adult Still's disease (ASD) is suggested, but the information is still lacking and the validation is insufficient. To determine the efficacy of several biologic agents in refractory ASD in Japan, a multicenter survey was performed. METHOD: Clinical data on 16 ASD patients who had been treated with at least 1 of the biological agents (total 24 occasions) were collected retrospectively. RESULTS: Infliximab was used in 9 cases, etanercept in 4, and tocilizumab in 11. Half of the patients that had been treated initially with infliximab or etanercept were changed to another biologics. Tocilizumab was effective in cases switched from another 2 drugs. Tocilizumab showed efficacy in treating both systemic and arthritic symptoms and showed apparent steroid-sparing effect and the highest continuation rate. CONCLUSION: Tocilizumab may be a promising biologic agent in refractory ASD.

[Case of microscopic polyangiitis and giant cell arteritis after influenza vaccination].

We report a case of microscopic polyangiitis (mPA) and giant cell arteritis (GCA) (polyangiitis overlap syndrome) after influenza vaccination. A 67-year-old female with chronic kidney disease, who had been observed by a physician, presented fever and headache after immunization of influenza vaccine. She was diagnosed as having with mPA and GCA based on symptoms, worsening of renal function, biopsy of temporal artery (giant cell arteritis) and skin (microscopic polyangiitis), pulmonary involvement and the presence of myeloperoxidase-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA). She was treated with prednisolone (PSL) and the symptoms were improved. However, two months later she was presented with general physical weariness. She was diagnosed as having with pneumocystis pneumonia, cytomegalovirus infection and cryptococcosis. Despite intensive treatment, she was died and autopsy was performed. The present case suggests that the influenza vaccination may cause different types of vasculitis, mPA and GCA, through the common mechanism in pathophysiology. This patient is also the first case of mPA and GCA proven by histological examination.

Interferon regulatory factor 5 is critical for the development of lupus in MRL/lpr mice.

OBJECTIVE: Interferon regulatory factor 5 (IRF-5) is a transcription factor that mediates intracellular signals activated by engagement of Toll-like receptors (TLRs). IRF5 polymorphisms are associated with an increased or decreased risk of systemic lupus erythematosus (SLE) in various human populations, but the precise role of IRF5 in SLE development is not fully understood. This study was undertaken to examine the role of IRF5 in the development of murine lupus. METHODS: We crossed gene-targeted IRF5-deficient (IRF5(-/-) ) mice with MRL/MpJ-lpr/lpr (MRL/lpr) mice and examined the progeny for survival, glomerulonephritis, autoantibody levels, immune system cell populations, and dendritic cell function. RESULTS: IRF5(-/-) MRL/lpr mice survived longer than control IRF5(+/+) MRL/lpr mice and displayed only very mild glomerulonephritis. Autoantibodies to SLE-related nuclear antigens were lower in IRF5(-/-) MRL/lpr mouse serum, and numbers of activated CD4+ T cells were reduced in the spleen. Splenic DCs from IRF5(-/-) MRL/lpr mice produced lower levels of inflammatory cytokines when treated in vitro with TLR-7 or TLR-9 ligands or immune complexes. Interferon-α production in response to CpG was also decreased. CONCLUSION: Our results show that IRF5 is a crucial driver of lupus development in mice, and indicate that IRF5 may be an attractive new target for therapeutic intervention to control disease in SLE patients.

Functional disturbance of the stress-adaptation system in patients with scleroderma.

There have been several reports indicating the association between recent stress experiences and the onset or the exacerbation of rheumatic diseases, although few such reports exist in patients with scleroderma (SSc). The present study was performed to elucidate whether there were any functional disturbances in the neuro-endocrine-immune system as a homeostatic system upon stress in SSc patients. Various serum levels of stress-related hormones and cytokines were examined before and after a mental calculation stress test, and a basal questionnaire study of sense of coherence (SOC, which is related to the ability to cope with stress), recent stress experiences, and quality of life (QOL) was performed in 17 SSc patients and in 38 healthy volunteers. Physical QOL state was impaired in patients, but there were no differences in recent stress experiences and SOC scores between patients and controls. Basal serum cortisol levels were similar in patients and controls, but increased levels of proinflammatory cytokine and noradrenalin were seen in SSc patients. Characteristically, contrary to the control group, whose cortisol levels increased significantly following the mental calculation stress test, no significant increase was observed in the patients when post-test cortisol levels were compared to pre-test levels, suggesting a defect in the normal cortisol response upon stress in SSc patients. The present results suggest that there may be impaired function of the neuro-endocrine-immune system upon stress in SSc patients.

[A case of cutaneous Mycobacterium nonchromogenicum infection suggesting sarcoidosis association].

A 67-year-old man clinically diagnosed a year earlier with sarcoidosis based on low-grade fever, lymphadenopathy, trunk skin rash, and histopathological skin tests was admitted for newly developing subcutaneous nodules on the trunk and arms and fever of 38 degrees C. Although initially suspected of recurrent sarcoidosis, he was diagnosed with Mycobacterium chromogenicum infection isolated from skin lesion culture. Combined clarithromycin of 800 mg/day, ethambutol of 750 mg/day, and embiomycin of 0.5 g/day was started, after which fever declined and WBC count and CRP decreased to normal in a week. One month later, skin lesions had disappeared. This case is interesting considering the association of nontuberculous mycobacterial infection with sarcoidosis.

Autoantibody-producing RP105(-) B cells, from patients with systemic lupus erythematosus, showed more preferential expression of BCMA compared with BAFF-R than normal subjects.

OBJECTIVE: B cells lacking RP105 produce autoantibodies in patients with SLE. Expression of B-cell activating factor (BAFF) binding receptors (BBRs) and survival of RP105(-) B cells from SLE patients were examined. METHODS: Detection of difference of gene expression between RP105(-) and RP105(+) B cells was done by DNA microarrays. Surface expression was confirmed by flow cytometry. The contribution of BAFF, a proliferation-inducing ligand (APRIL) and monomers/trimers of sCD40L to survival of RP105(-) and RP105(+) B cells was examined. RESULTS: Gene expression of B-cell maturation antigen (BCMA) was different among BBRs in RP105(-) and RP105(+) B cells in SLE. Preferential expression of BCMA on RP105(-) B cells was confirmed compared with RP105(+) B cells by flow cytometry, although BAFF receptor (BAFF-R) expression on RP105(-) B cells was significantly lower. Additionally, relative ratios of BCMA/BAFF-R expression on RP105(-) B cells were increased significantly in SLE patients compared with normal subjects. Stimulation by sCD40L decreased the number of surviving RP105(-) and RP105(+) B cells in vitro. RP105(+) B cells were not rescued from sCD40L-induced cell death by BAFF and/or APRIL. In contrast, either BAFF or APRIL maintained the survival of RP105(-) B cells due to avoidance of cell death. Activated RP105(-) B cells reduced BAFF-R and increased BCMA levels. CONCLUSIONS: RP105(-) B cells from SLE patients showed more preferential expression of BCMA compared with BAFF-R than normal subjects, and were possibly regulated by BAFF/APRIL. Our results provide a new insight of BCMA and their ligands in B cells from SLE patients.

Cyclosporin A treatment for Japanese patients with severe adult-onset Still's disease.

For over 10 years there have been no clinical studies about adult-onset Still's disease (AOSD) in Japan. We aimed to investigate recent clinical features and treatment of AOSD and to evaluate the efficacy of cyclosporin A (CyA) in the treatment of AOSD. The data from 34 patients with AOSD who were admitted to our hospital between 1994 and 2007 were analyzed retrospectively. Of several immunosuppressive agents, the efficacy of CyA given to seven patients was precisely evaluated. Clinical features observed in this study did not differ from those in our previous study, and serum ferritin levels were elevated in all the patients. Among immunosuppressive agents CyA, used concomitantly with corticosteroids (CS) for seven patients with severe AOSD, proved to be very effective. The disease was led to remission promptly by CyA in six patients, and all the patients except one experienced no recurrence. These results suggest that CyA can be one of the potent candidates to be used next to CS for patients with AOSD that is resistant to CS.

Toll-like receptor homolog RP105 modulates the antigen-presenting cell function and regulates the development of collagen-induced arthritis.

INTRODUCTION: RP105 is a Toll-like receptor homolog expressed on B cells, dendritic cells (DCs), and macrophages. We investigated the role of RP105 in the development of collagen-induced arthritis (CIA). METHODS: CIA was induced in RP105-deficient DBA/1 mice and the incidence and arthritis index were analyzed. The cytokine production by spleen cells was determined. The functions of the DCs and regulatory T cells (Tregs) from RP105-deficient or control mice were determined by adding these cells to the lymph node cell culture. Arthritis was also induced by incomplete Freund's adjuvant (IFA) plus collagen or by injecting anti-collagen antibody and lipopolysaccharide. RESULTS: RP105-deficient mice showed accelerated onset of arthritis and increased severity. Interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha production by spleen cells from RP105-deficient mice was increased in comparison with that from wild-type mice. The DCs from RP105-deficient mice induced more IFN-gamma production, whereas Tregs from those mice showed less inhibitory effect against IFN-gamma production. RP105-deficient mice also showed more severe arthritis induced by collagen with IFA. CONCLUSIONS: These results indicate that RP105 regulates the antigen-presenting cell function and Treg development, which induced the attenuation of the cell-mediated immune responses and, as a result, suppressed the development of CIA.

Nocardiosis in adult-onset Still's disease and vasculitis syndrome.

Four cases of nocardiosis in patients with adult-onset Still disease and vasculitis syndrome are presented. Three patients developed lung abscesses and 1 case developed a brain abscess. All were treated with high-dose corticosteroids, and 3 were given cyclosporine when they developed nocardiosis. All patients were successfully treated with antibiotics; cyclosporine was discontinued in 2 cases. These cases indicate that systemic nocardiosis can develop in patients with various rheumatologic diseases who are treated with corticosteroid and immunosuppressive drugs such as cyclosporine.