Systematic review and meta-analysis for the 2024 update of the Japan College of Rheumatology clinical practice guidelines for the management of rheumatoid arthritis.

OBJECTIVES: To update evidence on the efficacy and safety of disease-modifying antirheumatic drugs (DMARDs) and provide information to the taskforce for the 2024 update of the Japan College of Rheumatology (JCR) clinical practice guidelines (CPG) for the management of rheumatoid arthritis (RA). METHODS: We searched various databases for randomised controlled trials on RA published until June 2022, with no language restriction. For each of the 15 clinical questions, 2 independent reviewers screened the articles, evaluated the core outcomes, and performed meta-analyses. RESULTS: Subcutaneous injection of methotrexate (MTX) showed similar efficacy to oral MTX in MTX-naïve RA patients. Ozoralizumab combined with MTX improved drug efficacy compared to the placebo in RA patients with inadequate response (IR) to csDMARD. Rituximab with and without concomitant csDMARDs showed similar efficacy to other bDMARDs in bDMARD-IR RA patients. Combined Janus kinase inhibitors and MTX achieved similar clinical responses and equal safety during a 4-year period compared to tumour necrosis factor inhibitors in MTX-IR RA patients. Biosimilars showed efficacy equivalent to that of the original bDMARDs in csDMARD-IR and bDMARD-IR RA patients. CONCLUSION: This systematic review provides latest evidence for the 2024 update of the JCR CPG for RA management.

Role of interferons (IFNs) in the differentiation of T peripheral helper (Tph) cells.

Interleukin (IL)-21-producing T peripheral helper (Tph) cells are thought to contribute to extra-follicular B cell activation and play a pathogenic role in autoimmune diseases. In this study, we investigated the relationship between Tph cells and interferons (IFNs) in several autoimmune diseases because our previous study demonstrated that type I IFNs promote the differentiation of IL-21-producing Tph-like cells. The frequency of Tph cells in the blood as well as serum IFN-α2a and IFN-λ1 were markedly elevated in patients with active systemic lupus erythematosus (SLE) compared to other autoimmune diseases or healthy controls. Notably, the frequency of Tph cells was positively correlated with the SLE disease activity index, serum IFN-α and serum IFN-λ1 in SLE patients. Additionally, we found that type III IFNs (IFN-λ1, IFN-λ2 and IFN-λ3) promote the differentiation of programmed cell death-1 (PD-1)+ CXCR5 -CD4+ T cells and enhance the secretion of IL-21, IFN-γ and CXCL13. IFN-λ1, like IFN-α, up-regulated the mRNA expression of IL21, IFNG, CXCL13, CD244, SLAMF7, GZMB, PRF1, CCR5 and PRDM1, whereas it down-regulated that of CXCR5 and BCL6, reflecting a Tph-related gene expression pattern. IFN-α in combination with IFN-λ1, IFN-λ2 or IFN-λ3 significantly increased the differentiation of PD-1+CXCR5- Tph-like cells and the secretion of Tph-related cytokines as compared with each IFN alone, suggesting a cooperative interaction. From these findings, it is highly probable that type III IFNs in addition to type I IFNs play a key role in the differentiation of Tph cells and that high levels of IFN-α and IFN-λ1 trigger the differentiation and expansion of Tph cells in SLE.

Deep remission within 12 months prevents renal flare and damage accrual in lupus nephritis.

OBJECTIVES: To evaluate the significance of achieving deep remission by induction therapy in lupus nephritis (LN) patients. METHODS: We assessed consecutive patients undergoing induction therapy for active LN. Achievement of complete renal response (CR) was defined as a urine protein creatinine ratio (UPCR) ≤0.5 g/gCr, and deep remission (DR) was defined as a UPCR ≤0.15 g/gCr with stabilisation of serum creatinine levels assessed every 2-3 months. We compared renal flare and damage accrual rates among patients with CR, CR without DR, and DR at 3, 6, and 12 months and later. RESULTS: Fifty-nine Asian patients were enrolled, and the median observation period was 48.6 months. Of these, 55 patients achieved CR, and 33 achieved DR within 12 months of receiving induction therapy. The patients with DR within 12 months experienced a significantly lower rate of subsequent renal flare (p<0.001) and damage accrual (p=0.046) than those without CR, those with DR after 12 months, and those with no DR but CR within 12 months. In addition, younger age, shorter disease duration, lower urine protein at baseline, and earlier renal response were associated with DR within 12 months. CONCLUSIONS: Achievement of DR within 12 months after induction therapy should be a treatment target for active LN, as it has implications for preventing renal flare and damage accrual.

Differences in the strength of inhibition of interleukin-6 signalling by subcutaneous sarilumab and tocilizumab in rheumatoid arthritis patients.

OBJECTIVES: To assess differences in the strength of inhibition of IL-6/STAT3 signalling induced by subcutaneously (sc) administered tocilizumab (TCZ) and sarilumab (SAR). METHODS: Data were collected on patients with rheumatoid arthritis (RA) who achieved low disease activity (Clinical Disease Activity Index [CDAI]≤10) following treatment with weekly or bi-weekly administration of 162 mg sc of TCZ (TCZ qw group, n=8; TCZ q2w group, n=8), bi-weekly doses of 200 mg sc of SAR (SAR q2w group, n=7), or MTX (n=8) as a control. The clinical characteristics of each group were collected, and the serum concentrations of IL-6 and soluble IL-6 receptor (sIL-6R) were measured using ELISA. Whole blood samples from each group were stimulated with 100 ng/ml of IL-6. The proportion of phosphorylated (p)STAT3-positive CD4+ T cells was measured using phosflow cytometric analysis. RESULTS: The proportion of pSTAT3-positive CD4+ T cells following stimulation with 100 ng/ml of recombinant human IL-6 was significantly different among the groups (median 1.8% [0.9-3.0] vs. 7.7% [2.9-8.0] vs. 12.5% [11.4-16.6] vs. 71.5% [68.0-78.5] for the TCZ qw, SAR q2w, TCZ q2w, and MTX control groups, respectively; p<0.01 for all comparisons). CONCLUSIONS: SAR 200 mg q2w showed significantly stronger inhibition of IL-6/STAT3 signalling than TCZ sc q2w but weaker inhibition than TCZ sc qw. The results of this study may be useful for adjusting the IL-6 blockade treatment for patients with RA.

Lupus low disease activity state within 12 months is associated with favourable outcomes in severely active systemic lupus erythematosus.

OBJECTIVES: To demonstrate the significance of the time to attain lupus low disease activity state (LLDAS) after remission induction therapy in patients with severely active SLE. METHODS: We enrolled 79 patients starting prednisolone ≥0.4 mg/kg/day for active lupus with a BILAG 2004 index of A ≥ 1 or B ≥ 2, or for severe flare based on the Safety of Estrogens in Lupus Erythematosus National Assessment-SLE Disease Activity Index (SELENA-SLEDAI). The time to LLDAS attainment was divided into ≤6, 6-12 and >12 months and non-LLDAS; associations between the timing of LLDAS and flares, damage accrual and ≥50% LLDAS attainment were examined. RESULTS: The mean SLEDAI was 17; median starting dose of prednisolone, 0.95 mg/kg/day; and mean observational period, 39.7 months. Six (7.6%) and 41 (51.9%) patients achieved LLDAS within 6 and 12 months. Patients with a shorter time to LLDAS achievement were more likely to spend ≥50% of the time in LLDAS and had a lower cumulative prednisolone dose; no differences were observed in damage accrual. Patients requiring longer than 12 months to achieve LLDAS had a higher prevalence of thrombocytopenia and those with non-LLDAS had lower renal function and a higher starting dose of prednisolone and steroid pulse therapy than those who achieved LLDAS within 12 months. CONCLUSION: Achieving LLDAS within 12 months of induction therapy may be favourable in patients with severely active SLE. The low frequency of LLDAS attainment in high-risk populations highlights the need for a new strategy for SLE treatment.

Overall survival and post-spontaneous regression relapse-free survival of patients with lymphoproliferative disorders associated with rheumatoid arthritis: a multi-center retrospective cohort study.

OBJECTIVES: To clarify factors affecting 5-year survival rates and relapse rates after spontaneous regression (SR) of lymphoproliferative disorders (LPDs) in patients with rheumatoid arthritis (RA). METHODS: This retrospective longitudinal study comprised 232 patients with RA diagnosed with LPDs between January 2000 and March 2017 at eight hospitals in Japan. The Kaplan-Meier method was used to analyze survival and the Cox proportional hazard model was applied to identify predictive factors. RESULTS: Among all patients, 1-, 2- and 5-year overall survival rates were 89.5%, 86.1%, and 78.2%, respectively. Multivariable analysis revealed four 5-year survival risk factors assessed at diagnosis: age above 70 years (p = .002), deep lymphadenopathy and/or more than one extranodal lesion (p = .008), Eastern Cooperative Oncology Group/Zubrod performance status of 2-4 (p = .004), and classic Hodgkin lymphoma (CHL) histology (p = .047). Among 143 patients who achieved SR, 2- and 5-year relapse rates were 14.2% and 24.9%, respectively. CHL histology (p = .003) and serum soluble interleukin-2 receptor levels exceeding 2000 IU/L (p = .014) were associated with post-SR relapse-free survival. Blood lymphocyte counts were significantly lower at relapse than at 3-6 months prior (p < .001). CONCLUSION: Assessment of the above risk factors and routine inspection of blood lymphocyte counts could aid in the care management of LPDs in RA.

Treatment of rheumatoid arthritis after regression of lymphoproliferative disorders in patients treated with methotrexate: a retrospective, multi-center descriptive study.

OBJECTIVES: To identify the optimal treatment for rheumatoid arthritis (RA) after the regression of lymphoproliferative disorders (LPDs). METHODS: The subjects were 232 patients with RA who developed LPD between 2000 and 2017 at seven hospitals participating in the LPD-WG study. Kaplan-Meier and Cox proportional regression analyses were performed to determine the factors associated with the rate of LPD relapse and the retention of biological disease-modifying antirheumatic drugs (bDMARDs). RESULTS: Treatment for RA was resumed in 138 patients after spontaneous regression of LPD after the discontinuation of methotrexate and in 52 patients after chemotherapy for LPD (persistent-LPD). LPD relapses occurred in 23 patients. Not DMARDs use but Hodgkin's lymphoma was identified as a risk factor for LPD relapse. In 88 RA patients treated with bDMARDs [tocilizumab, 39 patients; abatacept 20 patients; tumor necrosis factor inhibitor, 29 patients], the one-year retention rate was 67.8%. The risk factors for discontinuation of bDMARDs were persistent-LPD, non-diffuse large B-cell lymphomas (non-DLBCL), and a high clinical disease activity index (CDAI). Tocilizumab showed the highest retention rate among bDMARDs, particularly in DLBCL. CONCLUSION: Although any bDMARD could be used in patients after LPD regression, effectiveness and risk for relapse should be carefully assessed for each LPD subtype.

Clinicopathological characteristics of lymphoproliferative disorders in 232 patients with rheumatoid arthritis in Japan: A retrospective, multicenter, descriptive study.

OBJECTIVE: To describe the clinicopathological characteristics of lymphoproliferative disorders (LPDs) in patients with rheumatoid arthritis (RA). METHODS: In this multicenter case series, we retrospectively reviewed the medical records of RA patients who were newly diagnosed as having LPDs with or without biopsy confirmation between 2000 and 2017 in eight hospitals in Japan. RESULTS: We included 232 patients with LPDs. The median age was 67 years (interquartile range [IQR], 60-73 years), and 77.1% were female. At the time of LPD diagnosis, 94.8% and 62.6% of the patients were methotrexate users and in remission or had low RA disease activity, respectively; lymphadenopathy and extranodal involvement were present in 77.1% and 51.9%, respectively. Major extranodal sites were the lungs and oral/oropharyngeal mucosa. The most common LPD pathological subtype was diffuse large B-cell lymphoma (40.5%), followed by classic Hodgkin lymphoma (10.8%), Epstein-Barr virus-positive mucocutaneous ulcer (7.7%), and reactive lymphoid hyperplasia (6.2%). The clinical and laboratory characteristics varied across the pathological subtypes. CONCLUSION: LPD occurred mainly in methotrexate users, while RA disease activity did not seem to be associated with LPD development. Although the clinical manifestations vary among pathological subtypes, manifestations of LPD in patients with RA can include lymphadenopathy, extranodal mass, and mucocutaneous ulcer.

Characteristics of rheumatoid arthritis with immunodeficiency-associated lymphoproliferative disorders to regress spontaneously by the withdrawal of methotrexate and their clinical course: A retrospective, multicenter, case-control study.

OBJECTIVE: To investigate clinical characteristics and time course of lymphoproliferative disorders (LPDs) in rheumatoid arthritis (RA) patients after methotrexate (MTX) discontinuation, in those who achieved spontaneous regression (SR). METHODS: We retrospectively reviewed clinical data from RA patients with LPDs obtained from eight institutions between 2000 and 2017 and compared clinical and pathological findings between SR and non-SR groups. RESULTS: Among 232 RA patients with LPDs, 216 were treated with MTX at the onset of LPD and 144 (66.7%) achieved SR after MTX discontinuation. Higher MTX doses, high titers of anti-CCP antibodies (>13.5 U/mL), and lower LDH and soluble IL-2 receptor levels were associated with SR. Lymphocyte count was decreased at LPD onset and increased at 2 weeks after MTX discontinuation in the SR group. Epstein-Barr virus-positive mucocutaneous ulcer, reactive lymphoid hyperplasia and unclassifiable B-cell lymphoma, were more frequent in the SR than in the non-SR group. In multivariable analysis, diffuse large B-cell lymphomas was an independent predictive factor for non-SR. In the patients with SR, 73.9% achieved partial or complete regression as early as 2 weeks after MTX discontinuation. CONCLUSION: SR and non-SR in RA patients with LPDs after MTX discontinuation were associated with certain clinical characteristics.

Milk fat globule epidermal growth factor 8 (MFG-E8) on monocytes is a novel biomarker of disease activity in systemic lupus erythematosus.

BACKGROUND: Milk fat globule epidermal growth factor (MFG-E8) is related secreted protein which links phosphatidylserine on apoptotic cells and integrin αvß3/5 on phagocytes. To clarify the clinical significance of MFG-E8 in SLE, we analyzed the correlation between expression level of MFG-E8 in circulating phagocytic leukocytes and clinical parameters of patients. METHODS: The study was conducted under a multi-center, prospective cohort design. Patients with one or both BILAG A or B, or SLEDAI- 2 K ≥ 4 with clinical symptoms were defined as the active SLE group. Expression of MFG-E8 on monocytes and concentration in serum were measured by FACS and ELISA, respectively. RESULTS: 96 subjects were enrolled. The absolute number and proportion of MFG-E8-positive monocytes to total monocytes were significantly higher in the active SLE group (p < 0.01). Importantly, the proportion was also significantly correlated with SLEDAI-2K, clinical SLEDAI, as well as serum levels of anti-ds-DNA antibody and complement and C1q. In addition, the proportion of MFG-E8-positive monocytes to total monocytes was significantly decreased from baseline in active SLE patients after 6 months' treatment and increased concordantly with disease activity in 6 refractory cases. Further, in receiver operating characteristic curve analysis for discrimination between active and inactive SLE, the AUC of the proportion of MFG-E8 was 0.854, which was equivalent to classical activity markers such as anti-ds DNA antibody (0.776), complement (0.897) and C1q (0.815). CONCLUSIONS: The proportion of MFG-E8-positive monocytes to total monocytes in peripheral blood was positively associated with disease activity in SLE and may be a novel biomarker of disease activity.

Tocilizumab monotherapy for large vessel vasculitis: results of 104-week treatment of a prospective, single-centre, open study.

OBJECTIVE: To evaluate the efficacy and safety of tocilizumab (TCZ) monotherapy for large vessel vasculitides (LVV), including Takayasu arteritis (TAK) and GCA. METHODS: Twelve patients with a newly diagnosed LVV (eight GCA, four TAK) were enrolled. One TAK patient withdrew consent, so 11 (eight GCA, three TAK) were analysed in a prospective, open-label study. TCZ (8 mg/kg) monotherapy, without glucocorticoids or immunosuppressants, was administered every 2 weeks for 2 months and then every 4 weeks for 10 months. Patients were followed for 1 year after the final TCZ dose. Complete and partial responses were defined as disappearance or improvement of all clinical symptoms and normalization of CRP. Relapse was defined as the worsening or recurrence of clinical symptoms, increase in CRP attributable to vasculitis, and/or the need for initiation of glucocorticoids and/or immunosuppressants. Poor clinical response described patients who did not fit the definition of complete response or partial response. RESULTS: Complete and partial responses rates were 75/66% and 25/0% in GCA/TAK patients, respectively, at week 24 and week 52. Five GCA patients and one TAK patient remained disease-free for 1 year after therapy. One GCA patient required TCZ discontinuation due to heart failure at week 24. CONCLUSION: TCZ monotherapy showed a high response rate for newly diagnosed LVV patients, and the majority of patients did not relapse for 1 year after TCZ cessation. Result of this study could help us to understand the crucial role of IL-6 in the pathogenesis of LVV.

Distinct patterns of lymphocyte count transition in lymphoproliferative disorder in patients with rheumatoid arthritis treated with methotrexate.

Objective: To clarify the characteristics of lymphoproliferative disorder (LPD) in patients with RA treated with MTX. Methods: Among 33 patients developing LPD during MTX treatment, 20 LPDs regressed spontaneously within 12 weeks after MTX cessation (regressive LPD), and 13 did not regress and most of them died or needed chemotherapy (persistent LPD). The control group consisted of 66 clinically matched MTX-treated RA patients without LPD. The clinical characteristics were compared between these three groups. Results: While no significant differences were found in clinical RA and LPD features among the three groups, the absolute lymphocyte number of the two LPD groups at LPD diagnosis was significantly lower than the control group (497/µl in the regressive vs 680/µl in the persistent vs 1400/µl in the control, P < 0.05). After MTX withdrawal, the lymphocyte number in the regressive group rapidly recovered to 1214/µl (P < 0.01) by week 2 and was thereafter maintained at an equivalent level to the control group. In contrast, lymphocyte level in the persistent group did not show significant increase throughout 12 weeks (620/µl at week 2, P = 0.57). Changes in lymphocyte number following MTX withdrawal clearly distinguished the regressive LPD from the persistent LPD. Conclusion: A significant decrease in lymphocyte count at the LPD diagnosis and its restoration after MTX withdrawal were markedly associated with spontaneous regression of LPD developing during MTX treatment.

Successful high-dose glucocorticoid therapy for anti-mitochondrial antibody-positive myocarditis arising during tocilizumab and low-dose glucocorticoid therapy for rheumatoid arthritis.

Anti-mitochondrial antibody (AMA)-positive myopathy, a recently identified condition with significant cardiac involvement, poses a serious challenge in treatment consensus due to its extreme rarity. While several studies demonstrate the efficacy of high-dose prednisolone in managing this disease, the current literature lacks substantial evidence regarding the effectiveness of biologic therapy or low-dose prednisolone for remission induction. Here, we present a case of AMA-positive myocarditis that emerged during rheumatoid arthritis treatment with tocilizumab (TCZ) and low-dose prednisolone (PSL). Successfully, intensive immunosuppressive therapy with high-dose PSL proved effective in stabilizing this condition. Our case highlights the necessity of a robust immunosuppressive approach, favoring high-dose PSL over the combination of low-dose PSL and TCZ in this disease.

Tense blisters and hemorrhagic bullae as the first manifestation of eosinophilic granulomatosis with polyangiitis.

Eosinophilic granulomatosis with polyangiitis (EGPA) poses a significant diagnostic challenge due to its varied clinical presentation. Here, we present a case of a 59-year-old female with a history of asthma and sinusitis, who manifested with an extremely rare presentation of drastic tense blisters and hemorrhagic bullae alongside purpuric lesions and peripheral neuropathy. Examinations revealed eosinophilia, positive anti-neutrophil cytoplasmic antibody, and characteristic pathological findings with small vessel vasculitis in the purpura. Treatment with glucocorticoids and cyclophosphamide led to rapid improvement in peripheral eosinophilia, skin manifestations and motor neuron deficits. Although rare, our case underscores that bullous skin lesions should be recognized as a potential cutaneous hallmark of EGPA to aid timely diagnosis, since prompt treatment initiation is crucial given the potential irreversible organ damage and poor prognosis of EGPA.

A Case of Successful Immunosuppressive Therapy for Interstitial Lung Disease Associated with Sjögren's Syndrome With Double-positive Anti-SS-A and Anti-centromere Antibodies.

Sjögren's syndrome (SS) can present with extraglandular organs, such as interstitial lung disease (ILD). Anti-SS-A antibody is frequently found in SS cases, whereas anti-centromere antibody (ACA) is detected in some SS cases. Notably, the anti-SS-A and ACA double-positive cases exhibited distinct features with a higher prevalence of ILD. However, there have so far been no reports on the treatment of ILD in anti-SS-A and ACA double-positive cases. We herein present a case of ILD with anti-SS-A and ACA double-positive SS that was successfully treated with immunosuppressive therapy. Our case suggests the potential efficacy of immunosuppressive therapy for this poorly understood condition.

Urinary biomarkers associated with pathogenic pathways reflecting histological findings in lupus nephritis.

OBJECTIVE: There is a pressing need to understand the pathogenesis of histological findings and identify the biomarkers for predicting the histological severity in lupus nephritis (LN). This study aimed to identify the pathogenic signal pathway and elucidate urinary biomarkers for predicting the presence or severity of histological findings in LN. METHODS: Urine samples from patients with biopsy-proven active LN were screened for 1305 proteins using an aptamer-based proteomic assay. The diversity and expansion of individual renal histological features in LN were quantified to identify the urinary proteins associated with the histological findings found in each score. Candidate urinary proteins were validated in a validation cohort. Immunohistochemical staining of the renal tissues was performed to clarify the localisation of the candidate proteins. RESULTS: Cluster analysis extracted five histological subgroups according to their correlations with each histological finding in LN. Protein groups which correlated with each histological subgroup revealed a distinct pathogenesis in LN using pathway analyses. Enzyme-linked immunosorbent assay validation revealed that urinary calgranulin B (S100A9), MCP-1, and IGFBP-5 levels could specifically predict the presence and severity of active glomerular lesions, interstitial inflammation, and interstitial fibrosis, respectively. Immunohistochemical staining revealed the localisation of these proteins in each lesion. CONCLUSIONS: Renal histological findings may reflect the different pathogeneses involved in each lesion, and estimating the urinary calgranulin B, MCP-1, and IGFBP-5 levels may be useful in predicting the presence and severity of histological findings in LN.

Longitudinal analysis at pre- and post-flare of T peripheral helper and T follicular helper subsets in patients with systemic lupus erythematosus.

OBJECTIVE: We focused to analyze the time-course changes at pre- and post-flare of T peripheral helper (Tph) cells and circulating T follicular helper (Tfh) cells in the blood of patients with systemic lupus erythematosus (SLE) with lupus low disease activity state (LLDAS) before flare. METHODS: This study included inactive (n = 29) and active (n = 55) patients with SLE. Tph subsets, Tfh subsets, CD11chi B cells, and plasma cells in the blood were determined by flow cytometry. The blood levels of cytokines including interferons (IFNs) were measured by electrochemiluminescence assay or cytokine beads array. RESULTS: Active SLE patients exhibited the increased frequency of Tph1, Tph2, Tfh1, and Tfh2 subsets when compared to inactive patients, but no clear changes in the other subsets. During the treatment with medications, Tph1, Tph2, and Tfh2 subsets were significantly reduced along with disease activity and Tph1 and Tph2 subsets were positively correlated with SLE disease activity index (SLEDAI). The time course analysis of patients at pre- and post-flare revealed that in the patients at LLDAS before flare, Tph subsets and Tfh subsets were relatively low levels. At the flare, Tph cells, particularly Tph1 and Tph2 subsets, were increased and correlated with SLEDAI. Furthermore, the blood levels of IFN-α2a, IFN-γ, and IFN-λ1 were low in the patients with LLDAS before flare but these IFNs, particularly IFN-λ1, were increased along with flare. CONCLUSION: Increased frequency of Tph1 and Tph2 subsets and elevated levels of serum IFN-λ1 are presumably critical for triggering of flare in SLE.

Risk of disease flares after SARS-CoV-2 mRNA vaccination in patients with systemic lupus erythematosus.

This study aims to elucidate the effectiveness and safety of SARS-CoV-2 mRNA vaccination in patients with systemic lupus erythematosus (SLE). We enrolled uninfected SLE patients who received two vaccine doses (BNT162b2 or mRNA-1273) and historical unvaccinated patients. Neutralizing antibodies, adverse reactions, and disease flares were evaluated 4 weeks after the second vaccination. Ninety patients were enrolled in each group. Among the vaccinated patients, SLE Disease Activity Index (SLEDAI), and prednisolone doses before vaccination were 2, and 5 mg/d, respectively. After the second vaccination, 19 (21.1%) had no neutralizing antibodies. Adverse reactions occurred in 88.9% within 3 d. Negative antibodies were associated with anemia and mycophenolate mofetil administration. SLEDAI increased modestly but significantly after vaccination, with 13 (14.4%) experiencing flares and 4 (4.4%) severe flares (nephritis in three and vasculitis in one). The flare rate was higher in vaccinated patients than unvaccinated controls. The mean duration between the second vaccination and flares was 35 d, and flares occurred at least 8 days after vaccination. Multivariable analysis showed that high SLEDAI and anti-dsDNA antibodies were associated with flares. The vaccine type, neutralizing antibody titer, and adverse reaction frequency did not affect flares. Therefore, residual disease activity before vaccination increases flare risk.