Endogenous interleukin (IL)‐17A promotes pristane‐induced systemic autoimmunity and lupus nephritis induced by pristane

Interleukin (IL)-17A is increased both in serum and in kidney biopsies from patients with lupus nephritis, but direct evidence of pathogenicity is less well established. Administration of pristane to genetically intact mice results in the production of autoantibodies and proliferative glomerulonephritis, resembling human lupus nephritis. These studies sought to define the role of IL-17A in experimental lupus induced by pristane administration. Pristane was administered to wild-type (WT) and IL-17A^−/− mice. Local and systemic immune responses were assessed after 6 days and 8 weeks, and autoimmunity, glomerular inflammation and renal injury were measured at 7 months. IL-17A production increased significantly 6 days after pristane injection, with innate immune cells, neutrophils (Ly6G⁺) and macrophages (F4/80⁺) being the predominant source of IL-17A. After 8 weeks, while systemic IL-17A was still readily detected in WT mice, the levels of proinflammatory cytokines, interferon (IFN)-γ and tumour necrosis factor (TNF) were diminished in the absence of endogenous IL-17A. Seven months after pristane treatment humoral autoimmunity was diminished in the absence of IL-17A, with decreased levels of immunoglobulin (Ig)G and anti-dsDNA antibodies. Renal inflammation and injury was less in the absence of IL-17A. Compared to WT mice, glomerular IgG, complement deposition, glomerular CD4⁺ T cells and intrarenal expression of T helper type 1 (Th1)-associated proinflammatory mediators were decreased in IL-17A^−/− mice. WT mice developed progressive proteinuria, but functional and histological renal injury was attenuated in the absence of IL-17A. Therefore, IL-17A is required for the full development of autoimmunity and lupus nephritis in experimental SLE, and early in the development of autoimmunity, innate immune cells produce IL-17A.     

Peroxisome proliferator‐activated receptor gamma agonists in the prevention and treatment of murine systemic lupus erythematosus

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are known to have many immunomodulatory effects. We have previously shown that the PPARγ agonist rosiglitazone is beneficial when used early in prevention of disease in murine models of systemic lupus erythematosus (SLE) and SLE-related atherosclerosis. In this report, we demonstrate that another PPARγ agonist, pioglitazone is also beneficial as a treatment for early murine lupus, indicating that this is a class effect and not agent-specific. We further attempt to define the ability of PPARγ agonists to ameliorate established or severe autoimmune disease using two mouse models: the MRL.lpr SLE model and the gld.apoE^−/− model of accelerated atherosclerosis and SLE. We demonstrate that, in contrast to the marked amelioration of disease seen when PPARγ agonist treatment was started before disease onset, treatment with rosiglitazone after disease onset in MRL.lpr or gld.apoE^−/− mice had minimal beneficial effect on the development of the autoimmune phenotype; however, rosiglitazone treatment remained highly effective at reducing lupus-associated atherosclerosis in gld.apoE^−/− mice after disease onset or when mice were maintained on a high cholesterol Western diet. These results suggest that beneficial effects of PPARγ agonists on the development of autoimmunity might be limited to the early stages of disease, but that atherosclerosis, a major cause of death in SLE patients, may be ameliorated even in established or severe disease.     

The role of neutrophils in skin damage induced by tissue‐deposited lupus IgG

Skin injury is the second most common clinical manifestation in patients with systemic lupus erythematosus (SLE). Neutrophils are crucial effector cells in the immune system but the significance of neutrophils in the pathogenesis of SLE is not clear. This study is to explore the role of neutrophils in the skin damage of SLE. We used lupus‐prone mice and a C57BL/6 mouse model of lupus serum IgG‐induced skin inflammation to investigate the role of neutrophils in skin damage of SLE. We found that a few neutrophils infiltrated the inflammatory sites of skin in lupus‐prone mice and the lupus‐IgG‐induced skin damage mouse model. Depletion of neutrophils did not affect the development of skin inflammation caused by lupus IgG, and lupus IgG can induce apoptosis of neutrophils. The apoptosis of neutrophils induced by lupus IgG is related to FcγRIII and Fas/Fas ligand pathways. Our study indicates that neutrophils are not major contributors in the skin damage caused by tissue‐deposited lupus IgG but death of neutrophils caused by lupus IgG may provide a resource of a large amount of autoantigens in SLE.     

A monoclonal antibody against CD86 and its protection in a murine lupus nephritis model of chronic graft-versus-host disease

Context: Lupus nephritis is the most common complication that causes the death of systemic lupus erythematosus patients. CD28/CTLA4 and their ligands CD80 or CD86 costimulatory pathway play a pivotal role in autoimmune disease and organ transplantation.

Objectives: We generated a monoclonal antibody (clone 1D1) against human CD86 (1D1) that could recognize both human and mouse CD86, and blocked the CD86/CD28 costimulatory pathway with our mAb on a murine lupus nephritis model induced with chronic graft-versus-host disease (cGVHD).

Materials and methods: Experimental lupus nephritis mice were induced with cGVHD, and splenocyte population were analyzed by flow cytometry. Autoantibodies and proteinuria were detected to evaluate the severity of lupus nephritis. The change of histopathology was observed by microscopy, fluorescence microscopy and electron microscopy.

Results: we successfully generated a monoclonal antibody against human CD86(1D1). 1D1 mAb could recognize not only human CD86, but also mouse CD86. 1D1 was applied to the cGVHD-induced experimental lupus nephritis model, and our study found the production of ANA and anti-dsDNA in the 1D1-treated group was lower than those in IgG-treated group after four weeks. The pathological injure of kidney in the 1D1-treated group was lighten than that in IgG-treated group.

Discussion and conclusions: Our data showed that blockade of CD86/CD28 with 1D1 induced a significant remission of proteinuria, production of autoantibodies, immune complex deposition and renal parenchyma lesions in experimental mice. Anti-CD86 Abs might be a potential method for immune therapy in autoimmune diseases and transplantation.     

Associations of B cell‐activating factor (BAFF) and anti‐BAFF autoantibodies with disease activity in multi‐ethnic Asian systemic lupus erythematosus patients in Singapore

To measure the levels of B cell‐activating factor (BAFF) and endogenous anti‐BAFF autoantibodies in a cohort of multi‐ethnic Asian systemic lupus erythematosus (SLE) patients in Singapore, to determine their correlation with disease activity. Serum samples from 121 SLE patients and 24 age‐ and sex‐matched healthy controls were assayed for BAFF and anti‐BAFF immunoglobulin (Ig)G antibody levels by enzyme‐linked immunosorbent assay (ELISA). The lowest reliable detection limit for anti‐BAFF‐IgG antibody levels was defined as 2 standard deviations (s.d.) from blank. Correlation of serum BAFF and anti‐BAFF IgG levels with disease activity [scored by SLE Activity Measure revised (SLAM‐R)], and disease manifestations were determined in these 121 patients. SLE patients had elevated BAFF levels compared to controls; mean 820 ± 40 pg/ml and 152 pg ± 45/ml, respectively [mean ± standard error of the mean (s.e.m.), P < 0·01], which were correlated positively with anti‐dsDNA antibody levels (r = 0·253, P < 0·03), and SLAM‐R scores (r = 0·627, P < 0·01). In addition, SLE patients had significantly higher levels of anti‐BAFF IgG, which were correlated negatively with disease activity (r = –0·436, P < 0·01), levels of anti‐dsDNA antibody (r = –0·347, P < 0·02) and BAFF (r = –0·459, P < 0·01). The majority of patients in this multi‐ethnic Asian SLE cohort had elevated levels of BAFF and anti‐BAFF antibodies. Anti‐BAFF autoantibody levels correlated negatively with clinical disease activity, anti‐dsDNA and BAFF levels, suggesting that they may be disease‐modifying. Our results provide further information about the complexity of BAFF pathophysiology in different SLE disease populations and phenotypes, and suggest that studies of the influence of anti‐cytokine antibodies in different SLE populations will be required when selecting patients for trials using targeted anti‐cytokine therapies.     

Anti-interleukin-6 monoclonal antibody inhibits autoimmune responses in a murine model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease resulting from dysregulation of the immune system. Interleukin-6 (IL-6) is a multifunctional cytokine produced by macrophages, monocytes and T and B cells. It stimulates B-cell differentiation/maturation, immunoglobulin secretion, and T-cell functions. Elevated levels of IL-6 in serum, urine and renal glomeruli were detected in patients with active SLE and in murine models of SLE. Our study investigated the role of IL-6 in an SLE-like disease in New Zealand Black/White (NZB/W) F1 mice by administration of an anti-murine IL-6 monoclonal antibody (mAb). Intraperitoneal administration of the anti-IL-6 mAb suppressed the production of anti-dsDNA autoantibody. B-cell proliferation induced by anti-IgM and anti-CD40 was lower in the anti-IL-6 mAb-treated mice, ex vivo studies demonstrated that anti-IL-6 mAb treatment inhibited anti-dsDNA production. Anti-CD3-induced T-cell proliferation and mixed lymphocyte reactions were inhibited by anti-IL-6 mAb treatment, indicating a partial down-regulation of T cells. Histological analysis showed that treatment with anti-IL-6 mAb prevented the development of severe kidney disease. These results suggest that treatment with anti-IL-6 mAb has a beneficial effect on autoimmunity in murine SLE and that autoreactive B cells may be the primary target for anti-IL-6 mAb treatment; its effect on autoreactive T cells is also indicated.     

Murine lupus strains differentially model unique facets of human lupus serology

Systemic lupus erythematosus (SLE) is a polygenic autoimmune disease characterized by the production of anti-nuclear autoantibodies that lead to subsequent end organ damage. Previous array-based studies in patients with SLE have shown that high immunoglobulin (Ig)G anti-nuclear autoantibody reactivity was associated with severe renal lupus, whereas IgM polyreactivity was associated with less severe disease. To ascertain how different murine lupus strains recapitulate these different autoantibody profiles seen in patients, serum from New Zealand black (NZB)/NZ white (W) F(1), Murphy Roths large (MRL)/lpr, NZ mixed (M)2410 and BXSB strains were compared using a comprehensive array-based screen. The array results were verified using enzyme-linked immunosorbent assays (ELISAs). Serum from MRL/lpr mice exhibited high levels of IgG anti-nuclear antibodies as well as anti-glomerular antibodies and variable levels of antibodies to myosin, Matrigel and thyroglobulin. Elevated anti-nuclear IgG antibodies were associated with severe nephritis in this strain. In contrast, NZM2410 mice exhibited lower IgG autoantibody levels with less severe nephritis but a significantly higher polyreactive IgM autoantibody profile. ELISA analysis confirmed these results. The NZB/NZW F(1) and BXSB strains exhibited an intermediate serological profile. Hence, just as in patients with SLE, whereas strong IgG reactivity to nuclear antigens is associated with severe renal disease, a polyreactive IgM seroprofile is also less ominous in murine lupus.     

Decreased levels of autoantibodies against apolipoprotein B‐100 antigens are associated with cardiovascular disease in systemic lupus erythematosus

Increased production of autoantibodies is a characteristic feature of systemic lupus erythematosus (SLE) and there is evidence that several of these autoantibodies may contribute to increased cardiovascular disease (CVD) in SLE. Autoantibodies against the apolipoprotein (apo) B‐100 peptides p45 and p210 have been associated with a lower CVD risk in non‐SLE cohorts. The aim of the present study was to investigate how SLE affects the occurrence of these potentially protective autoantibodies. The study cohort consisted of 434 SLE patients and 322 age‐ and sex‐matched population controls. Antibodies against native and malondialdehyde (MDA)‐modified p45 and p210 were measured by enzyme‐linked immunosorbent assay (ELISA). SLE patients had significantly lower levels of p210 immunoglobulin (Ig)G and p45 IgM (both the native and malondialdehyde (MDA)‐modified forms). SLE patients with manifest CVD (myocardial infarction, ischaemic cerebrovascular disease or peripheral vascular disease) had lower levels p210 IgG and p45 IgM than SLE patients without CVD. Decreased levels of these autoantibodies were also observed in SLE patients with permanent organ damage, as assessed by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (ACR) Damage Index (SDI). The present findings show that patients with SLE, a condition generally characterized by abundance of autoantibodies of multiple specificities, have reduced levels of antibodies against the apo B‐100 antigens p45 and p210 and that the levels of these antibodies are reduced further in SLE patients with CVD. These observations suggest the possibility that an impaired antibody‐mediated removal of damaged LDL particles may contribute to the development of vascular complications and organ damage in SLE.     

Dnase1‐deficient mice spontaneously develop a systemic lupus erythematosus‐like disease

Systemic lupus erythematosus (SLE) is an autoimmune disease that has high morbidity and can result in multi‐organ damage. SLE is characterized by dysregulated activation of T‐ and B‐lymphocytes and the production of autoantibodies directed against nuclear components. The endonuclease deoxyribonuclease 1 (DNase1) is abundant in blood and a subset of SLE patients have mutations in DNASE1. Furthermore, a report showed that Dnase1‐deficient mice develop an SLE‐like disease, but these mice also carry a deletion of the gene adjacent to Dnase1, which encodes the chaperone TRAP1/HSP75. We generated a murine strain deficient in Dnase1 with an intact Trap1 gene to examine if a lack of DNase1 is responsible for the development of a spontaneous SLE‐like disease. We show that the Dnase1‐deficient mice do indeed develop an SLE‐like phenotype with elevated autoantibody production by 9 months and kidney damage by 12 months. Notably, this model recapitulates the female bias seen in human SLE patients since female Dnase1‐deficient mice produced the highest concentrations of autoantibodies and had more severe kidney damage than males. Since there is currently no cure for SLE the protective role of DNase1 as demonstrated in our study remains of great therapeutic interest.     

Urinary haptoglobin,alpha‐1 anti‐chymotrypsin and retinol binding protein identified by proteomics as potential biomarkers for lupus nephritis

The study was aimed at identification by proteomics and validation by enzyme‐linked immunosorbent assay (ELISA) of potential urinary biomarkers for lupus nephritis. Study subjects comprised 88 systemic lupus erythematosus (SLE) patients and 60 controls (rheumatoid arthritis, diabetes mellitus and healthy individuals). Based on the SLE disease activity index (SLEDAI), patients were classified as active renal (AR), active non‐renal (ANR) or inactive disease (ID). Urinary proteins from a group of patients with AR or ID were resolved by two‐dimensional gel electrophoresis and identified by matrix‐assisted laser desorption ionization–time of flight–mass spectrometry (MALDI‐TOF‐MS/MS). The selected biomarkers were validated by ELISA using samples from all patients and controls. AR patients were followed‐up for 12 months after start of therapy. Three urinary proteins, alpha‐1 anti‐chymotrypsin (ACT), haptoglobin (HAP) and retinol binding protein (RBP), were detected in patients with AR and not ID. Upon validation, ACT levels were higher in AR patients than the other groups (P < 0·001) and showed good correlation with renal SLEDAI (r = 0·577, P < 0·001) as well as SLEDAI (r = 0·461, P < 0·001). Similarly, HAP levels were > 10‐fold higher in AR than other groups (P < 0·001) and correlated well with renal SLEDAI (r = 0·594, P < 0·001) and SLEDAI (r = 0·371, P < 0·01). RBP levels were also higher in AR patients than in other groups (P < 0·05), except diabetes, and showed moderate correlation with renal SLEDAI (r = 0·284, P < 0·008) and SLEDAI (r = 0·316, P < 0·003). Upon follow‐up with treatment, levels of all three proteins declined at 6 and 12 months (P < 0·01). Multiple logistic regression identified ACT as the best marker to differentiate AR from ANR. Urinary HAP, ACT and RBP are potential biomarkers for lupus nephritis activity.     

Soluble MHC class II‐driven therapy for a systemic lupus erythematosus murine experimental in vitro and in vivo model

Taking into consideration the multiparametric nature of systemic lupus erythematosus (SLE ), the severity and variability of symptoms and the lack of effective therapeutic approaches, this study took advantage of the recently described role of soluble major histocompatibility complex class II (sMHCII ) molecules in maintaining tolerance to the organism and attempted to apply sMHCII proteins as a treatment to murine SLE experimental models in vitro as well as in vivo. After breaking tolerance to DNA in vitro, which was accompanied by development of specific anti‐dsDNA antibodies, syngeneic or allogeneic sMHCII molecules, purified from healthy mouse serum, could significantly reduce the specific antibody levels and drive the system towards immunosuppression, as assessed by specific marker analysis on T cells and cytokine production by flow cytometry and ELISA , respectively. The in vivo experimental model consisted of pristane‐induced SLE symptoms to BALB /c mice, which developed maximal levels of anti‐dsDNA 2 months after pristane inoculation. Syngeneic or allogeneic sMHCII administration could alleviate pristane‐induced symptoms, significantly decrease specific anti‐dsDNA antibody production and develop immunosuppression to the host, as manifested by increase of CD 4 + CTLA ‐4 +  and CD 4 + CD 25 +  cell populations in the spleen. Thus, the results presented in this study introduced the ability of sMHCII proteins to suppress specific autoantigen response, opening new areas of research and offering novel therapeutic approaches to SLE with expanding features to other autoimmune diseases.     

Oestrogen up‐regulates interleukin‐21 production by CD4+ T lymphocytes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which abnormal immune responses are mediated by tissue‐binding autoantibodies and immune complex deposition. Because most SLE patients are women of child‐bearing age, oestrogen has been suggested to play an important role in SLE pathogenesis. One proposed role is to induce B‐cell activation, culminating in increased autoantibody production. Interleukin‐21 (IL‐21) has been shown to be crucial in the differentiation of activated B cells into plasma cells. We therefore hypothesized that oestrogen up‐regulates IL‐21 production and induces subsequent B‐cell activation in SLE patients. Peripheral blood was obtained from 22 SLE patients and 16 healthy controls. Expression levels of IL‐21 and its receptor in serum, peripheral blood mononuclear cells, and CD4⁺ T cells were higher in SLE patients than in healthy controls. Exposure of CD4⁺ T cells from SLE patients to 17β‐oestradiol led to a dose‐ and time‐dependent increase in IL‐21 expression, which was abolished in the presence of mitogen‐activated protein kinase (MAPK) (MAPK kinase, p38, Jun N‐terminal kinase) inhibitors. B cells from healthy controls showed increased antibody production when they were co‐cultured with oestrogen‐treated CD4⁺ T cells from SLE patients. Treatment with IL‐21 antibody abrogated the increased antibody production of the co‐culture systems. This study revealed the association between oestrogen and IL‐21 in SLE patients. Oestrogen up‐regulates IL‐21 expression of CD4⁺ T cells via MAPK‐dependent pathways in SLE patients, which in turn induces increased antibody production by B cells.     

Modulation of autoreactive responses of peripheral blood lymphocytes of patients with systemic lupus erythematosus by peptides based on human and murine anti-DNA autoantibodies

Two peptides, based on the sequences of the complementarity-determining regions (CDR) 1 and 3 of a pathogenic murine monoclonal anti-DNA autoatibody that bears the 16/6 idiotype (Id), were shown to either prevent or treat an already established systemic lupus erythematosus (SLE) in two murine models of lupus. Two additional peptides based on the human monoclonal anti-DNA, 16/6 Id were synthesized. This study was undertaken in order to investigate the ability of the CDR-based peptides to immunomodulate SLE-associated responses of peripheral blood lymphocytes (PBL) of SLE patients. PBL of 24 of the 62 SLE patients tested proliferated in vitro following stimulation with the human 16/6 Id. Peptides based on the CDRs of both the human and murine anti-DNA autoantibodies inhibited efficiently and specifically the 16/6 Id-induced proliferation and IL-2 production. The latter inhibitions correlated with an up-regulated production (by 2.5-3.5-fold) of the immunosuppressive cytokine, TGF-beta. Overall, the results of our study demonstrate that the CDR-based peptides are capable of down-regulating in vitro autoreactive T cell responses of PBL of SLE patients. Thus, these peptides are potential candidates for a novel specific treatment of SLE patients.     

Serum antibodies to human leucocyte antigen (HLA)‐E,HLA‐F and HLA‐G in patients with systemic lupus erythematosus (SLE) during disease flares: Clinical relevance of HLA‐F autoantibodies

T lymphocyte hyperactivity and progressive inflammation in systemic lupus erythematosus (SLE) patients results in over‐expression of human leucocyte antigen (HLA)‐Ib on the surface of lymphocytes. These are shed into the circulation upon inflammation, and may augment production of antibodies promoting pathogenicity of the disease. The objective was to evaluate the association of HLA‐Ib (HLA‐E, HLA‐F and HLA‐G) antibodies to the disease activity of SLE. The immunoglobulin (Ig)G/IgM reactivity to HLA‐Ib and β2m in the sera of 69 German, 29 Mexican female SLE patients and 17 German female controls was measured by multiplex Luminex^®‐based flow cytometry. The values were expressed as mean florescence intensity (MFI). Only the German SLE cohort was analysed in relation to the clinical disease activity. In the controls, anti‐HLA‐G IgG predominated over other HLA‐Ib antibodies, whereas SLE patients had a preponderance of anti‐HLA‐F IgG over the other HLA‐Ib antibodies. The disease activity index, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)‐2000, was reflected only in the levels of anti‐HLA‐F IgG. Anti‐HLA‐F IgG with MFI level of 500–1999 was associated with active SLE, whereas inactive SLE revealed higher MFI (>2000). When anti‐HLA‐F IgG were cross‐reactive with other HLA‐Ib alleles, their reactivity was reflected in the levels of anti‐HLA‐E and ‐G IgG. The prevalence of HLA‐F‐monospecific antibodies in SLE patients was also associated with the clinical disease activity. Anti‐HLA‐F IgG is possibly involved in the clearance of HLA‐F shed from lymphocytes and inflamed tissues to lessen the disease's severity, and thus emerges as a beneficial immune biomarker. Therefore, anti‐HLA‐Ib IgG should be considered as a biomarker in standard SLE diagnostics.     

Immunoregulation therapy changes the frequency of interleukin (IL)‐22+CD4+ T cells in systemic lupus erythematosus patients

T cell and T cell‐related cytokine abnormalities are involved in the pathogenesis of systemic lupus erythematosus (SLE). Our previous study showed that the interleukin (IL)‐22⁺CD4⁺T cells and IL‐22 play an important role in the pathogenesis of SLE. In this study, we aimed to investigate the effects of glucocorticoids (GCs) and immunodepressant agents on IL‐22 and IL‐22‐producing T cell subsets in SLE patients. The frequencies of peripheral blood T helper type 22 (Th22), IL‐22⁺Th17, IL‐22⁺Th1 and Th17 cells and the concentrations of serum IL‐22, IL‐17 and interferon (IFN)‐γ in SLE patients receiving 4 weeks of treatment with cyclophosphamide (CYC), methylprednisolone and hydroxychloroquine (HCQ) were characterized by flow cytometry analysis and enzyme‐linked immunosorbent assay (ELISA). The frequencies of Th22, IL‐22⁺ Th17 and Th17 cells and the concentrations of IL‐22 and IL‐17 were reduced in response to the drugs methylprednisolone, cyclophosphamide and hydroxychloroquine for 4 weeks in the majority of SLE patients. However, the percentage of Th1 cells showed no change. No differences in the levels of IL‐22 and IL‐22⁺CD4⁺ T cells were found between non‐responders and health controls either before or after therapy. IL‐22 levels were correlated positively with Th22 cells in SLE patients after treatment. These results suggest that elevated IL‐22 is correlated with IL‐22⁺CD4⁺T cells, especially Th22 cells, and may have a co‐operative or synergetic function in the immunopathogenesis of SLE. GC, CYC and HCQ treatment may regulate the production of IL‐22, possibly by correcting the IL‐22⁺CD4⁺T cells polarizations in SLE, thus providing new insights into the mechanism of GC, CYC and HCQ in the treatment of SLE.     

Urinary B cell activating factor (BAFF) and a proliferation‐inducing ligand (APRIL): potential biomarkers of active lupus nephritis

B cell activating factor (BAFF) and a proliferation‐inducing ligand (APRIL) help in B cell activation, maintenance and plasma cell survival. B cell infiltration has been demonstrated in kidneys of patients with lupus nephritis (LN). Serum levels of BAFF and APRIL have shown inconsistent relationships with lupus disease activity. We evaluated urinary levels of BAFF and APRIL as biomarker for LN. Thirty‐six patients with proliferative lupus nephritis (AN), 10 with active lupus without nephritis (AL) and 15 healthy controls (HC) were studied. APRIL and BAFF levels were measured in both serum and urine using enzyme‐linked immunosorbent assay (ELISA). Urine levels were normalized for urinary creatinine excretion. Urine levels were correlated with conventional disease activity markers and histology. Levels were reassessed in 20 AN patients at 6 months after treatment with cyclophosphamide. Urinary APRIL (uAPRIL) and BAFF (uBAFF) levels were raised significantly in AN. uAPRIL, but not uBAFF, correlated moderately with renal Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in AN (r = 0·36, P < 0·05). On receiver operator curve (ROC) analysis, uBAFF and uAPRIL showed an area under the curve (AUC) of 0·825 and 0·781, respectively, in differentiating between nephritis and non‐nephritis, which performed better than low C3, C4 and raised anti‐dsDNA antibodies. There was no correlation of serum levels with uBAFF (r = 0·187, P = 0·261) and uAPRIL (r = 0·114, P = 0·494). uAPRIL levels reduced after treatment (mean 125 pg/mg to 36 pg/mg, P < 0·05). uBAFF levels reduced in 16 responders while two of four non‐responders had increase in levels. Thus, uBAFF and uAPRIL are potential biomarkers of proliferative lupus nephritis.     

Anti‐dsDNA antibodies as a classification criterion and a diagnostic marker for systemic lupus erythematosus: critical remarks

Antibodies to mammalian dsDNA have, for decades, been linked to systemic lupus erythematosus (SLE) and particularly to its most serious complication, lupus nephritis. This canonical view derives from studies on its strong association with disease. The dogma was particularly settled when the antibody was included in the classification criteria for SLE that developed during the 1970s, most prominently in the 1982 American College of Rheumatology (ACR), and recently in The Systemic Lupus International Collaborating Clinics (SLICC) classification criteria. There are several problems to be discussed before the anti‐dsDNA antibody can be accepted without further distinction as a criterion to classify SLE. Old and contemporary knowledge make it clear that an anti‐dsDNA antibody is not a unifying term. It embraces antibodies with a wide spectrum of fine molecular specificities, antibodies that are produced transiently in context of infections and persistently in the context of true autoimmunity, and also includes anti‐dsDNA antibodies that have the potential to bind chromatin (accessible DNA structures) and not (specificity for DNA structures that are embedded in chromatin and therefore unaccessible for the antibodies). This critical review summarizes this knowledge and questions whether or not an anti‐dsDNA antibody, as simply that, can be used to classify SLE.     

Promoter polymorphisms of the TIM‐4 gene are correlated with disease activity in patients with systemic lupus erythematosus

Although the TIM gene family plays important roles in immune responses, little is known about TIM regulation in the development of systemic lupus erythematosus (SLE). This study aimed to investigate the association of two TIM‐4 single nucleotide polymorphisms (SNPs) rs6874202 (?1419G>A) and rs62382402 (?1609G>A) with SLE susceptibility in a Chinese Han population. The results showed no significant differences between patients with SLE and control group for rs6874202 and rs62382402 (p = .72, .53 respectively). However, the anti‐dsDNA levels in serum from SLE patients with GG genotype of TIM‐4 gene at ‐1419 site were significantly higher than those with GA and AA genotype (p = .0335), and C3 levels of SLE patients with GG and GA genotype were much lower than those with AA genotypes (p = .0187). Moreover, the apoptotic cell levels of SLE patients with AA and GG genotypes were significantly higher than those with GA genotypes in patients with SLE (p = .0393). In addition, the C3 concentration of SLE patients with the GG genotype of TIM‐4 gene at ‐1609 site was found to be significantly higher than those with the GA genotype (p = .0129). The results imply that GG genotype of the TIM‐4 gene at ‐1419 site might be associated with the disease activity of SLE.