Reduced expressions of apoptosis-related proteins TRAIL, Bcl-2, and TNFR1 in NK cells of juvenile-onset systemic lupus erythematosus patients: relations with disease activity, nephritis, and neuropsychiatric involvement

Background

Lupus pathogenesis is mainly ascribed to increased production and/or impaired clearance of dead cell debris. Although self-reactive T and B lymphocytes are critically linked to lupus development, neutrophils, monocytes, and natural killer (NK) cells have also been implicated. This study assessed apoptosis-related protein expressions in NK cells of patients with juvenile-onset systemic lupus erythematosus (jSLE) and relations to disease activity parameters, nephritis, and neuropsychiatric involvement.

Methods

Thirty-six patients with jSLE, 13 juvenile dermatomyositis (JDM) inflammatory controls, and nine healthy controls had Fas, FasL, TRAIL, TNFR1, Bcl-2, Bax, Bim, and caspase-3 expressions in NK cells (CD3-CD16+CD56+) simultaneously determined by flow cytometry. Disease activity parameters included Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, erythrocyte sedimentation rate, C-reactive protein level, anti-double strain DNA antibody level, complement fractions C3 and C4 levels.

Results

Patients with jSLE had a profile of significantly reduced expression of TRAIL, Bcl-2, and TNFR1 proteins in NK cells when compared to healthy controls. Similar profile was observed in patients with jSLE with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. Patients with jSLE with positive anti-dsDNA also had reduced expression of Bax in NK cells when compared healthy controls and to those with negative anti-dsDNA. Yet, patients with jSLE with negative anti-dsDNA had reduced mean fluorescence intensity (MFI) of Bim in NK cells compared to healthy controls. Patients with jSLE with nephritis also had reduced MFI of Fas in NK cells when compared to those without nephritis. In addition, in patients with jSLE, the proportion of FasL-expressing NK cells directly correlated with the SLEDAI-2K score (rs = 0.6, p = 0.002) and inversely correlated with the C3 levels (rs = -0.5, p = 0.007). Moreover, patients with jSLE had increased NK cell percentage and caspase-3 protein expression in NK cells when compared to JDM controls.

Conclusion

This study extends to NK cells an altered profile of TRAIL, Bcl-2, TNFR1, Fas, FasL, Bax, Bim, and caspase-3 proteins in patients with jSLE, particularly in those with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. This change in apoptosis-related protein expressions may contribute to the defective functions of NK cells and, consequently, to lupus development. The full clarification of the role of NK cells in jSLE pathogenesis may pave the way for new therapies like those of NK cell-based.

Cf-02, a novel benzamide-linked small molecule, blunts NF-κB activation and NLRP3 inflammasome assembly and improves acute onset of accelerated and severe lupus nephritis in mice

In the present study, acute onset of severe lupus nephritis was successfully treated in mice using a new, benzamide-linked, small molecule that targets immune modulation and the NLRP3 inflammasome. Specifically, 6-(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenyl)-2H-benzo[e][1,3]oxazine-2,4(3H)-dione (Cf-02) (a) reduced serum levels of IgG anti-dsDNA, IL-1β, IL-6, and TNF-α, (b) inhibited activation of dendritic cells and differentially regulated T cell functions, and (c) suppressed the NF-κB/NLRP3 inflammasome axis, targeting priming and activating signals of the inflammasome. Moreover, treatment with Cf-02 significantly inhibited secretion of IL-1β in lipopolysaccharide-stimulated macrophages, but this effect was abolished by autophagy induction. These results recommend Cf-02 as a promising drug candidate for the serious renal conditions associated with systemic lupus erythematosus. Future investigations should examine whether Cf-02 may also be therapeutic in other types of chronic kidney disease involving NLRP3 inflammasome-driven signaling.

Increased sMer, but not sAxl, sTyro3, and Gas6 relate with active disease in juvenile systemic lupus erythematosus

INTRODUCTION/OBJECTIVES

Tyro3, Axl, and Mer (TAM) receptors and ligands mediate apoptotic bodies engulfment which alteration has been related with juvenile systemic lupus erythematosus (JSLE) pathogenesis. Thus, the aim was to determine their soluble levels.

METHODS

Serum sTyro3, sAxl, sMer, and Gas6 levels were measured using ELISA in 67 JSLE patients, 12 juvenile idiopathic arthritis (JIA) inflammatory and 20 healthy controls and related with SLEDAI-2K score, anti-dsDNA antibody, ESR, CRP, C3, C4 levels, and nephritis.

RESULTS

JSLE patients with active disease (SLEDAI-2K> 4) had significantly increased sMer levels compared with healthy controls (median 8.4 vs. 6.0 ng/mL, p = 0.009) and inactive disease patients (5.2 ng/mL, p = 0.0003). sMer levels correlated with SLEDAI-2K (r = 0.44; p = 0.0004) and ESR (r = 0.24; p = 0.04), while sAxl correlated with SLEDAI-2K (r = 0.33; p = 0.008) and C4 levels (r = - 0.24; p = 0.04). JSLE patients taking glucocorticoid had increased sAxl and sMer levels. Moreover, sAxl correlated with sMer and sTyro3 levels. Patients with nephritis and those with focal or diffuse proliferative glomerulonephritis had these protein levels similar to healthy controls and patients without renal involvement. sTyro3 levels of JSLE patients taking glucocorticoid were decreased, and correlated with Gas6 and sAxl, while Gas6 levels correlated with age upon enrollment. JIA controls had protein levels similar to healthy controls and JSLE patients.

CONCLUSIONS

This study reinforces that sMer is increased in active JSLE patients, yet sMer and sAxl correlates with disease activity parameters, and their alterations are disease-specific. However, further studies are needed to determine exact roles of sTyro3 and Gas6 in disease pathogenesis. Key Points • sMer and sAxl serum levels are related with active disease in JSLE patients • sMer correlated with SLEDAI-2K score in JSLE • sTyro3, sAxl, sMer and Gas6 levels did not related with nephritis in JSLE patients • sTyro3 and Gas6 exact roles in JSLE are not established and further studies are needed.

Increased Soluble Cytoplasmic Bcl-2 Protein Serum Levels and Expression and Decreased Fas Expression in Lymphocytes and Monocytes in Juvenile Dermatomyositis

OBJECTIVE

To evaluate soluble Fas antigen (sFas), sFas ligand (sFasL), soluble tumor necrosis factor-related apoptosis-inducing ligand, and soluble cytoplasmic Bcl-2 protein (sBcl-2) serum levels, Fas and Bcl-2 expressions in T and B lymphocytes and monocytes and relations with erythrocyte sedimentation rate, C-reactive protein (CRP), Childhood Myositis Assessment Scale, and manual muscle testing in juvenile dermatomyositis (JDM).

METHODS

Serum levels were determined by ELISA and peripheral cell expressions by flow cytometry for patients with JDM or juvenile idiopathic arthritis (JIA), and healthy controls.

RESULTS

Patients with JDM had increased sBcl-2, which correlated with CRP. Expression of Bcl-2 was increased and expression of Fas was decreased in CD3+, CD4+, and CD8+ T lymphocytes compared with JIA and/or healthy controls.

CONCLUSION

Patients with JDM presented a unique apoptosis-related proteins profile, which may contribute to disease development.

Evans Syndrome at Childhood-Onset Systemic Lupus Erythematosus Diagnosis: A Large Multicenter Study

BACKGROUND

Evans syndrome (ES) in childhood-onset systemic lupus erythematosus (cSLE) patients has been rarely reported and limited to small populations.

PROCEDURES

A retrospective multicenter cohort study (Brazilian cSLE group) was performed in 10 Pediatric Rheumatology services including 850 patients with cSLE. ES was assessed at disease diagnosis and defined by the combination of immune thrombocytopenia and autoimmune hemolytic anemia.

RESULTS

ES was observed in 11 of 850 (1.3%) cSLE patients. The majority of them had hemorrhagic manifestations (91%) and active disease (82%). All patients with ES were hospitalized and none died. Comparisons of cSLE patients with and without ES at diagnosis revealed similar frequencies of female gender, multiorgan involvement, autoantibodies profile, and low complement (P > 0.05). Patients with ES had a lower frequency of malar rash (9% vs. 53%, P = 0.003) and musculoskeletal involvement (18% vs. 69%, P = 0.001) than those without this complication. The frequencies of intravenous methylprednisolone (82% vs. 43%, P = 0.013) and intravenous immunoglobulin use (64% vs. 3%, P < 0.0001) were significantly higher in the ES group, with similar current prednisone dose between groups (1.1 [0.76-1.5] vs. 1.0 mg/kg/day [0-30], P = 0.195).

CONCLUSIONS

Our large multicenter study identified ES as a rare and severe initial manifestation of active cSLE with good outcome. Diagnosis is challenging due to the lack of typical signs and symptoms of lupus and the requirement to exclude infection and primary immunodeficiency.