Sustained depression of B cell counts in lupus nephritis after treatment with rituximab and/or belimumab is associated with fewer disease flares.

OBJECTIVE: To study the risk of lupus nephritis flare (LNF) or severe lupus flare (SLF) as a function of B cell count kinetics in lupus nephritis (LN) patients after they achieve at least a partial renal response (PRR) with induction treatment that includes rituximab (RTX) and/or belimumab (BLM). METHODS: We performed a retrospective analysis of a cohort of 19 patients with severe LN that received a B cell agent (BCA), RTX and/or BLM, as part of an initial treatment regimen for an LN flare and had subsequent CD19+ B cell measurements in peripheral blood. We then characterized the follow-up periods, after B cell depressions occurred and PRR were achieved, by the corresponding trajectories of B cell counts (BCC). Time periods with sustained low BCC were type 1 (T1) episodes, while those with repletion of BCC>100 cells/µL were called type 2 (T2) episodes. Time periods with rapid BCC repletion, defined as >50 cells/µL in ≤6 months, were called T2b episodes. Corresponding C3, C4, and anti-dsDNA levels were recorded for each episode. The time from PRR until an event, either a LNF or SLF, or to censoring, either at the end of the study period or the end of available patient follow-up, was assessed for each episode type. Kaplan-Meier survival analysis was used to compare time to flare between T1 and T2 episodes. RESULTS: There were 26 episodes of B cell depression. Seventeen (65%) were T1 and 9 (35%) were T2. Compared to T1 episodes, T2 episodes were 9.0 times more likely to result in flare over the follow-up period (hazard ratio (HR) = 9.0, 95% CI for HR = 2.2-36.7); this risk was even larger for T2b vs T1 episodes. Median BCC was 14 cells/µL in T1 and 160 cells/µL in T2 episodes. Both C3 and C4 levels significantly increased over the duration of the episode in T1 episodes only. CONCLUSION: Sustained low BCC was associated with prolonged serologic and clinical response, whereas repletion, and particularly rapid repletion, of B cells after treatment with BCA was associated with subsequent disease flare.

Standing on Shoulders: Interferon Research From Viral Interference to Lupus Pathogenesis and Treatment.

The discovery of interferon in the 1950s represents much more than the identification of the first cytokine and the key mediator of antiviral host defense. Defining the molecular nature and complexity of the type I interferon family, as well as its inducers and molecular mechanisms of action, was the work of investigators working at the highest level and producing insights of great consequence. Current knowledge of receptor-ligand interactions, cell signaling, and transcriptional regulation derives from studies of type I interferon. It is on the shoulders of the giants who produced that knowledge that others stand and have revealed critical mechanisms of the pathogenesis of systemic lupus erythematosus and other autoimmune diseases. The design of novel therapeutics is informed by the advances in investigation of type I interferon, with the potential for important impact on patient management.

Low Peripheral B-Cell Counts in Patients With Systemic Rheumatic Diseases Due to Treatment With Belimumab and/or Rituximab Are Associated With Low Antibody Responses to Primary COVID-19 Vaccination.

Background: Immunosuppressive agents inhibit COVID-19 vaccine antibody (Ab) responses in patients with systemic rheumatic diseases. Rituximab may fully block Ab responses when B cells become undetected. The effect of detected but low number of B cells due to treatment with a B-cell agent (belimumab and/or rituximab) has not been established. Purpose: We sought to examine whether there is an association between a low number of B cells due to treatment with belimumab and/or rituximab and impaired primary COVID-19 vaccination spike Ab responses in patients with systemic rheumatic diseases. Methods: We retrospectively examined Ab responses to COVID-19 vaccinations, especially in relation to B-cell counts after treatment with belimumab and/or rituximab, in 58 patients with systemic rheumatic diseases: 22 on and 36 not on B-cell agents. We used Kruskal-Wallis and Mann-Whitney U tests for comparison of Ab values between the groups and Fisher exact test for relative risk calculations. Results: Median (interquartile range) postvaccination Ab responses were lower in patients on versus those not on B-cell agents: 3.91 (0.77-20.00) versus 20.00 (14.32-20.00), respectively. Among patients on belimumab and/or rituximab, Ab responses of less than 25% of the assay's upper limit were exclusively observed in those with B-cell counts lower than 40/µL. Patients with B-cell counts lower than 40/µL exhibit a relative risk of 6.092 (95% CI: 2.75-14.24) for Ab responses of less than 25% of the upper limit compared with patients not on B-cell agents. This relative risk remained significant, even after excluding patients with undetected B cells. Conclusion: This retrospective study found an association between low B-cell counts (less than 40/µL) and decreased Ab responses to primary COVID-19 vaccination in patients with systemic rheumatic diseases treated with belimumab and/or rituximab. Despite the small number of patients studied, these findings add to the accumulating evidence on the importance of B-cell count in predicting spike Ab responses to COVID-19 vaccination.

Type I interferon and neutrophil transcripts in lupus nephritis renal biopsies: clinical and histopathological associations.

OBJECTIVES: To investigate the expression of type I IFN (IFN-I) and neutrophil transcripts in kidney tissue from patients with different classes of LN and their association with distinct clinical and histopathological features. METHODS: Quantitation of IFN-I, defensin-α3 and formyl peptide receptor-like 1 (FPRL-1) transcripts was performed in kidney biopsy tissue from 24 patients with various classes of LN (6 class III, 14 class IV, 4 class V) and 3 control samples. Patient demographics, glomerular filtration rate (eGFR) and histopathological characteristics, including activity and chronicity indices, were analysed. RESULTS: IFNα2 and IFNß transcripts were overexpressed in renal tissues from patients with proliferative forms of LN (III/IV) compared with patients with membranous nephritis and control kidneys. Patients with LN and impaired renal function, attested by eGFR, displayed higher relative expression of IFNα2 transcripts in renal tissues compared with those with normal renal function (23.0 ± 16.2 vs 12.0 ± 14.8, P = 0.04). Defensin-α3, but not FPRL-1, transcripts were overexpressed in LN tissues, particularly those with segmental necrotizing lesions, and were correlated with higher renal pathological activity indices (r = 0.61, P = 0.02), urinary protein levels (r = 0.44, P = 0.048) and IFNα2 expression (r = 0.50, P = 0.01). CONCLUSION: IFN-I transcripts are expressed locally in kidneys from patients with proliferative LN and are associated with impaired renal function. Elevated defensin-α3 transcripts, a neutrophil product associated with neutrophil extracellular traps, may identify a driver of local IFN-I expression. These findings provide insights into the mechanisms of proliferative LN and may inform therapeutic decisions regarding selection of IFN-I pathway inhibitors.

Chronic activation of pDCs in autoimmunity is linked to dysregulated ER stress and metabolic responses.

Plasmacytoid dendritic cells (pDCs) chronically produce type I interferon (IFN-I) in autoimmune diseases, including systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). We report that the IRE1α-XBP1 branch of the unfolded protein response (UPR) inhibits IFN-α production by TLR7- or TLR9-activated pDCs. In SSc patients, UPR gene expression was reduced in pDCs, which inversely correlated with IFN-I-stimulated gene expression. CXCL4, a chemokine highly secreted in SSc patients, downregulated IRE1α-XBP1-controlled genes and promoted IFN-α production by pDCs. Mechanistically, IRE1α-XBP1 activation rewired glycolysis to serine biosynthesis by inducing phosphoglycerate dehydrogenase (PHGDH) expression. This process reduced pyruvate access to the tricarboxylic acid (TCA) cycle and blunted mitochondrial ATP generation, which are essential for pDC IFN-I responses. Notably, PHGDH expression was reduced in pDCs from patients with SSc and SLE, and pharmacological blockade of TCA cycle reactions inhibited IFN-I responses in pDCs from these patients. Hence, modulating the IRE1α-XBP1-PHGDH axis may represent a hitherto unexplored strategy for alleviating chronic pDC activation in autoimmune disorders.

Belimumab or anifrolumab for systemic lupus erythematosus? A risk-benefit assessment.

Treatment of systemic lupus erythematosus (SLE) currently employs agents with relatively unselective immunosuppressive properties. However, two target-specific biological drugs have been approved: belimumab (anti-B-cell-activating factor/BAFF) and anifrolumab (anti-interferon alpha receptor-1/IFNAR1). Here, we performed a comparative risk-benefit assessment for both drugs based on the role of BAFF and IFNAR1 in host defense and the pathogenesis of SLE and by considering the available data on safety and efficacy. Due to differences in target expression sites, anti-IFNAR1, but not anti-BAFF, might elicit organ-specific effects, consistent with clinical efficacy data. The IFNAR1 is specifically involved in innate and adaptive antiviral immunity in most cells of the body. Consistent with this observation, the available safety data obtained from patients negatively selected for LN and neuropsychiatric SLE, primary immunodeficiencies, splenectomy and chronic HIV, HBV, HCV infections suggest an increased risk for some viral infections such as varicella zoster and perhaps influenza. In contrast, BAFF is mainly involved in adaptive immune responses in lymphoid tissues, thus anti-BAFF therapy modulates SLE activity and prevents SLE flares without interfering with local innate host defense mechanisms and should only marginally affect immune memory to previous pathogen exposures consistent with the available safety data from SLE patients without chronic HIV, HBV or HCV infections. When using belimumab and anifrolumab, careful patient stratification and specific precautions may minimize risks and maximize beneficial treatment effects for patients with SLE.

A case of inflammatory cerebral amyloid angiopathy after ischemic stroke - a potential risk factor related to blood-brain barrier disruption.

Cerebral Amyloid Angiopathy (CAA) is a cerebrovascular disease prevalent in elderly patients and strongly associated with cognitive decline and intracranial hemorrhage. Inflammatory forms of CAA (CAA-Related Inflammation i.e. CAA-ri and Amyloid-Beta Related Angiitis i.e. ABRA) are responsible for rapid neurocognitive decline, but are highly responsive to corticosteroid treatment. We present a patient with history of CAA who developed probable CAA-ri/ABRA three months after an acute ischemic stroke. We review the literature and imaging criteria for CAA-ri/ABRA, and propose further research for any association between these entities and blood-brain barrier disruption in the setting of ischemia.

Venous Thromboembolic Events in African American Lupus Patients in Association With Antiphospholipid Antibodies Compared to White Patients.

OBJECTIVE: The risk of thrombotic events is elevated in patients with systemic lupus erythematosus (SLE) compared to the general population and has been attributed to both systemic inflammation and to the presence of antiphospholipid antibodies (aPLs). Our objective was to examine differences in aPL prevalence in White and African American patients with SLE and venous thromboembolic (VTE) events, and to compare inflammatory markers at the time of a VTE event. METHODS: Records of White and African American patients with SLE and VTE events were retrieved from a rheumatology practice based at an academic hospital. A clinically significant aPL profile was defined as anti-cardiolipin IgG/IgM and/or anti-ß2 -glycoprotein I IgG/IgM ≥40 units, and/or positive lupus anticoagulant ≥1.3. Logistic regression was used to determine predictors of a clinically significant aPL profile. RESULTS: Ninety-seven patients fulfilled American College of Rheumatology and/or 2012 Systemic Lupus Erythematosus International Collaborating Clinics classification criteria for SLE, had a history of VTE events, and had available aPL tests (59 White and 38 African American patients). African American patients were 66% less likely (95% confidence interval 0.12-0.96; P = 0.04) to have a clinically significant aPL profile compared to White patients in multivariable regression. Triple positivity was most frequent among White patients, while 7 of 8 African American patients had a positive lupus anticoagulant test. At the time of a VTE event, African American patients had significantly higher levels of anti-double-stranded DNA (P = 0.02), lower hemoglobin (P = 0.01), and higher erythrocyte sedimentation rate (P = 0.008). CONCLUSION: Among patients with SLE and VTE events, African American patients were less likely to have a clinically significant aPL profile compared to White patients, indicating that a negative aPL profile in African American patients does not decrease VTE risk.

Expression of APOBEC family members as regulators of endogenous retroelements and malignant transformation in systemic autoimmunity.

OBJECTIVE: To explore whether APOBEC family members are involved in the response to inappropriate expression of L1 retroelements in primary Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE), as well as in SS related lymphomagenesis. METHODS: Minor salivary glands (MSG) and kidney biopsy (KB) specimens were obtained from 41 SS patients (10 with lymphoma) and 23 patients with SLE, respectively. PBMC and sera were also collected from 73 SLE patients. Full-length L1 transcripts, members of the APOBEC and IFN family were quantitated by real time PCR. Type I IFN activity was assessed in lupus plasma by a cell assay. RESULTS: APOBEC3A was increased in SS MSG, SLE KB and PBMC and correlated with L1. AID and APOBEC3G were particularly overexpressed in MSG tissues derived from SS lymphoma patients. CONCLUSION: These data reveal a previously unappreciated role of APOBEC family proteins in the pathogenesis of systemic autoimmunity and SS related lymphomagenesis.

Phase II Randomized Trial of Rituximab Plus Cyclophosphamide Followed by Belimumab for the Treatment of Lupus Nephritis.

OBJECTIVE: To assess the safety, mechanism of action, and preliminary efficacy of rituximab followed by belimumab in the treatment of refractory lupus nephritis (LN). METHODS: In a multicenter, randomized, open-label clinical trial, 43 patients with recurrent or refractory LN were treated with rituximab, cyclophosphamide (CYC), and glucocorticoids followed by weekly belimumab infusions until week 48 (RCB group), or treated with rituximab and CYC but no belimumab infusions (RC group). Patients were followed up until week 96. Percentages of total and autoreactive B cell subsets in the patients' peripheral blood were analyzed by flow cytometry. RESULTS: Treatment with belimumab did not increase the incidence of adverse events in patients with refractory LN. At week 48, a complete or partial renal response occurred in 11 (52%) of 21 patients receiving belimumab, compared to 9 (41%) of 22 patients in the RC group who did not receive belimumab (P = 0.452). Lack of improvement in or worsening of LN was the major reason for treatment failure. B cell depletion occurred in both groups, but the percentage of B cells remained lower in those receiving belimumab (geometric mean number of B cells at week 60, 53 cells/µl in the RCB group versus 11 cells/µl in the RC group; P = 0.0012). Percentages of total and autoreactive transitional B cells increased from baseline to week 48 in both groups. However, percentages of total and autoreactive naive B cells decreased from baseline to week 48 in the belimumab group compared to the no belimumab RC group (P = 0.0349), a finding that is consistent with the observed impaired maturation of naive B cells and enhanced censoring of autoreactive B cells. CONCLUSION: The addition of belimumab to a treatment regimen with rituximab and CYC was safe in patients with refractory LN. This regimen diminished maturation of transitional to naive B cells during B cell reconstitution, and enhanced the negative selection of autoreactive B cells. Clinical efficacy was not improved with rituximab and CYC in combination with belimumab when compared to a therapeutic strategy of B cell depletion alone in patients with LN.

Responsiveness of the Patient-Reported Outcomes Measurement Information System Global Health Short Form in Outpatients With Systemic Lupus Erythematosus.

OBJECTIVE: To evaluate the longitudinal responsiveness (sensitivity to change) of the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health Short Form (PROMIS10) in outpatients with systemic lupus erythematosus (SLE). METHODS: Outpatients with SLE who were receiving care at an academic medical center completed the PROMIS10 at 2 visits that were a minimum of 1 month apart. Responsiveness of the PROMIS10 global physical and mental health domains to Patient-Reported improvement or deterioration of health status was evaluated, as measured by standard validated instruments. Effect sizes of changes in PROMIS10 scores between visits were evaluated using Kruskal-Wallis testing. RESULTS: A total of 223 SLE patients enrolled and completed baseline surveys, with 186 (83.4%) completing a second set of questionnaires. The PROMIS10 demonstrated mild-to-moderate responsiveness to Patient-Reported improvement (effect size 0.29) and worsening (effect sizes -0.27 and -0.54) of health status for both global physical health and global mental health. Changes in the PROMIS10 correlated poorly with changes in physician-reported measures of disease activity. CONCLUSION: The PROMIS10 showed responsiveness over time to Patient-Reported changes in SLE health status, but not physician-assessed changes. These data suggest that the PROMIS10 can be used to efficiently measure and monitor important aspects of the SLE patient experience that are not captured by standard physician-derived metrics. Further studies are needed to evaluate the role of the PROMIS10 in optimizing longitudinal disease management in SLE and to determine its responsiveness in other chronic health conditions.

Type I Interferons in Autoimmune Disease.

Type I interferons, which make up the first cytokine family to be described and are the essential mediators of antivirus host defense, have emerged as central elements in the immunopathology of systemic autoimmune diseases, with systemic lupus erythematosus as the prototype. Lessons from investigation of interferon regulation following virus infection can be applied to lupus, with the conclusion that sustained production of type I interferon shifts nearly all components of the immune system toward pathologic functions that result in tissue damage and disease. We review recent data, mainly from studies of patients with systemic lupus erythematosus, that provide new insights into the mechanisms of induction and the immunologic consequences of chronic activation of the type I interferon pathway. Current concepts implicate endogenous nucleic acids, driving both cytosolic sensors and endosomal Toll-like receptors, in interferon pathway activation and suggest targets for development of novel therapeutics that may restore the immune system to health.

Feasibility, Validity, and Reliability of the 10-item Patient Reported Outcomes Measurement Information System Global Health Short Form in Outpatients with Systemic Lupus Erythematosus.

OBJECTIVE: To assess the feasibility, validity, and reliability of the Patient Reported Outcomes Measurement Information System Global Health Short Form (PROMIS10) in outpatients with systemic lupus erythematosus (SLE). METHODS: SLE outpatients completed PROMIS10, Medical Outcomes Study Short Form-36 (SF-36), LupusQoL-US, and selected PROMIS computerized adaptive tests (CAT) at routine visits at an SLE Center of Excellence. Construct validity was evaluated by correlating PROMIS10 physical and mental health scores with PROMIS CAT, legacy instruments, and physician-derived measures of disease activity and damage. Test-retest reliability was determined among subjects reporting stable SLE activity at 2 assessments 1 week apart using intraclass correlation coefficients (ICC). RESULTS: A diverse cohort of 204 out of 238 patients with SLE (86%) completed survey instruments. PROMIS10 physical health scores strongly correlated with physical function, pain, and social health domains in PROMIS CAT, SF-36, and LupusQoL, while mental health scores strongly correlated with PROMIS depression CAT, SF-36, and LupusQoL mental health domains (Spearman correlations ≥ 0.70). Active arthritis, comorbid fibromyalgia (FM), and anxiety were associated with worse PROMIS10 scores, but sociodemographic factors and physician-assessed flare status were not. Test-retest reliability for PROMIS10 physical and mental health scores was high (ICC ≥ 0.85). PROMIS10 required < 2 minutes to complete. CONCLUSION: PROMIS10 is valid and reliable, and can efficiently screen for impaired physical function, pain, and emotional distress in outpatients with SLE. With strong correlations to LupusQoL and SF-36 but significantly reduced responder burden, PROMIS10 is a promising tool for measuring patient-reported outcomes in routine SLE clinical care and value-based healthcare initiatives.

Plasmacytoid dendritic cells promote systemic sclerosis with a key role for TLR8.

Systemic sclerosis (SSc) is a multisystem life-threatening fibrosing disorder that lacks effective treatment. The link between the inflammation observed in organs such as the skin and profibrotic mechanisms is not well understood. The plasmacytoid dendritic cell (pDC) is a key cell type mediating Toll-like receptor (TLR)-induced inflammation in autoimmune disease patients, including lupus and skin diseases with interface dermatitis. However, the role of pDCs in fibrosis is less clear. We show that pDCs infiltrate the skin of SSc patients and are chronically activated, leading to secretion of interferon-α (IFN-α) and CXCL4, which are both hallmarks of the disease. We demonstrate that the secretion of CXCL4 is under the control of phosphatidylinositol 3-kinase δ and is due to the aberrant presence of TLR8 on pDCs of SSc patients, which is not seen in healthy donors or in lupus pDCs, and that CXCL4 primarily acts by potentiating TLR8- but also TLR9-induced IFN production by pDCs. Depleting pDCs prevented disease in a mouse model of scleroderma and could revert fibrosis in mice with established disease. In contrast, the disease was exacerbated in mice transgenic for TLR8 with recruitment of pDCs to the fibrotic skin, whereas TLR7 only partially contributed to the inflammatory response, indicating that TLR8 is the key RNA-sensing TLR involved in the establishment of fibrosis. We conclude that the pDC is an essential cell type involved in the pathogenesis of SSc and its removal using depleting antibodies or attenuating pDC function could be a novel approach to treat SSc patients.

Defective regulation of L1 endogenous retroelements in primary Sjogren's syndrome and systemic lupus erythematosus: Role of methylating enzymes.

OBJECTIVE: To investigate whether altered DNA methylation contributes to the inappropriate expression of LINE-1 (L1) retroelements in primary Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE). METHODS: Minor salivary glands (MSG) were obtained from 42 patients with primary SS [23 without adverse predictors for lymphoma development (SS-low risk), 7 SS-high risk and 12 complicated by B-cell lymphoma (SS-lymphoma)] and 17 sicca controls (SC). Additionally, kidney biopsy specimens and PBMCs were obtained from 23 and 73 lupus patients, respectively. Relative mRNA expression was quantified for full-length L1 transcripts, along with mediators of methylation. In an independent set of 44 MSG samples (11 SS-low risk, 10 SS-high risk, 15 SS-lymphoma and 8 SC), methylation levels of the L1 promoter were determined by bisulphite pyrosequencing. RESULTS: A strong positive correlation was demonstrated between L1 transcripts and gene products that mediate de novo and constitutive DNA methylation, DNA methyltransferase (DNMT)3B, DNMT1, and methyl CpG binding protein 2 (MeCP2), in both SS MSG and lupus renal tissues. A significant negative correlation was observed between expression of L1 and lymphoid-specific helicase (LSH, encoded by HELLS) in both SS MSG and SLE kidney tissues, as well as between DNMT3A transcripts and L1 expression in SLE kidney tissues and PBMCs. Reduced levels of L1 promoter methylation along with increased DNMT3B, DNMT1, and MeCP2, but reduced LSH levels were detected in SS-low risk patients compared to both SS-lymphoma and SC. The SS-lymphoma group was also characterized by a profound decrease of MeCP2 and DNMT3B compared to SC. CONCLUSION: Our data support a contributory role of altered methylation mechanisms in the pathogenesis of systemic autoimmune disorders and related lymphoproliferative processes and suggest that LSH and DNMT3A should be investigated as candidate upstream mediators of decreased L1 promoter methylation and increased L1 expression.

Validity and Reliability of Patient Reported Outcomes Measurement Information System Computerized Adaptive Tests in Systemic Lupus Erythematosus.

OBJECTIVE: The aims of this study were to assess the construct validity and the test-retest reliability of Patient Reported Outcomes Measurement Information System (PROMIS) computerized adaptive tests (CAT) in patients with systemic lupus erythematosus (SLE). METHODS: Adults with SLE completed the Medical Outcomes Study Short Form-36, LupusQoL-US version ("legacy instruments"), and 14 selected PROMIS CAT. Using Spearman correlations, PROMIS CAT were compared with similar domains measured with legacy instruments. CAT were also correlated with the Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) disease activity and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) scores. Test-retest reliability was evaluated using ICC. RESULTS: There were 204 outpatients with SLE enrolled in the study and 162 completed a retest. PROMIS CAT showed good performance characteristics and moderate to strong correlations with similar domains in the 2 legacy instruments (r = -0.49 to 0.86, p < 0.001). However, correlations between PROMIS CAT and the SELENA-SLEDAI disease activity and SDI were generally weak and statistically insignificant. PROMIS CAT test-retest ICC were good to excellent, ranging from 0.72 to 0.88. CONCLUSION: To our knowledge, these data are the first to show that PROMIS CAT are valid and reliable for many SLE-relevant domains. Importantly, PROMIS scores did not correlate well with physician-derived measures. This disconnect between objective signs and symptoms and the subjective patient disease experience underscores the crucial need to integrate patient-reported outcomes into clinical care to ensure optimal disease management.

Targeting the RhoA-ROCK pathway to reverse T-cell dysfunction in SLE.

OBJECTIVES: Deregulated production of interleukin (IL)-17 and IL-21 contributes to the pathogenesis of autoimmune disorders such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Production of IL-17 and IL-21 can be regulated by ROCK2, one of the two Rho kinases. Increased ROCK activation was previously observed in an SLE cohort. Here, we evaluated ROCK activity in a new SLE cohort, and an RA cohort, and assessed the ability of distinct inhibitors of the ROCK pathway to suppress production of IL-17 and IL-21 by SLE T cells or human Th17 cells. METHODS: ROCK activity in peripheral blood mononuclear cells (PBMCs) from 29 patients with SLE, 31 patients with RA and 28 healthy controls was determined by ELISA. SLE T cells or in vitro-differentiated Th17 cells were treated with Y27632 (a pan-ROCK inhibitor), KD025 (a selective ROCK2 inhibitor) or simvastatin (which inhibits RhoA, a major ROCK activator). ROCK activity and IL-17 and IL-21 production were assessed. The transcriptional profile altered by ROCK inhibitors was evaluated by NanoString technology. RESULTS: ROCK activity levels were significantly higher in patients with SLE and RA than healthy controls. Th17 cells exhibited high ROCK activity that was inhibited by Y27632, KD025 or simvastatin; each also decreased IL-17 and IL-21 production by purified SLE T cells or Th17 cells. Immune profiling revealed both overlapping and distinct effects of the different ROCK inhibitors. CONCLUSIONS: ROCK activity is elevated in PBMCs from patients with SLE and RA. Production of IL-17 and IL-21 by SLE T cells or Th17 cells can furthermore be inhibited by targeting the RhoA-ROCK pathway via both non-selective and selective approaches.

Novel molecular signatures in mononuclear cell populations from patients with systemic lupus erythematosus.

To gain novel insights into the immunopathogenesis of systemic lupus erythematosus we have analyzed gene expression data from isolated CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK-cell enriched peripheral blood cell fractions from patients and healthy donors. As predicted, type I interferon-inducible gene transcripts are overexpressed in all populations. Transcripts preferentially expressed in SLE CD4+ and CD8+ T cells include those associated with Tregulatory and Th17 effector cell programs, respectively, but in each case additional transcripts predicted to limit differentiation of those effector cells are detected. Evidence for involvement of the Wnt/ß-catenin pathway was observed in both B and T cell fractions, and novel transcripts were identified in each cell population. These data point to disrupted T effector cell differentiation and the Wnt/ß-catenin pathway as contributors to immune dysfunction in SLE while further supporting a central role for the type I interferon pathway in lupus.