Inquiry into murine and human lupus

Exercise-induced modulation of Interferon-signature: a therapeutic route toward management of Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a multisystemic autoimmune disorder characterized by flares-ups/remissions with a complex clinical picture related to disease severity and organ/tissue injury, which, if left untreated, may result in permanent damage. Enhanced fatigue and pain perception, worsened quality of life (QoL) and outcome are constant, albeit symptoms may differ. An aberrant SLE immunoprofiling, note as "interferon (IFN)α-signature", is acknowledged to break immunotolerance. Recently, a deregulated "IFNγ-signature" is suggested to silently precede/trigger IFNα profile before clinical manifestations. IFNα- and IFNγ-over-signaling merge in cytokine/chemokine overexpression exacerbating autoimmunity. Remission achievement and QoL improvement are the main goals. The current therapy (i.e., corticosteroids, immunosuppressants) aims to downregulate immune over-response. Exercise could be a safe treatment due to its ever-emerging ability to shape and re-balance immune system without harmful side-effects; in addition, it improves cardiorespiratory capacity and musculoskeletal strength/power, usually impaired in SLE. Nevertheless, exercise is not yet included in SLE care plans. Furthermore, due to the fear to worsening pain/fatigue, SLE subjects experience kinesiophobia and sedentary lifestyle, worsening physical health. Training SLE patients to exercise is mandatory to fight inactive behavior and ameliorate health. This review aims to focus the attention on the role of exercise as a non-pharmacological therapy in SLE, considering its ability to mitigate IFN-signature and rebalance (auto)immune response. To this purpose, the significance of IFNα- and IFNγ-signaling in SLE etiopathogenesis will be addressed first and discussed thereafter as biotarget of exercise. Comments are addressed on the need to make aware all SLE care professional figures to promote exercise for health patients.

AHR/TET2/NT5E axis downregulation is associated with the risk of systemic lupus erythematosus and its progression

The prognosis of systemic lupus erythematosus (SLE) is unpredictable. This study aimed to examine the regulatory mechanism of the AHR/TET2/NT5E pathway during SLE progression. The AHR, TET2 and NT5E expression levels were examined in T regulatory cells (Tregs) of patients with SLE. The correlation of AHR, TET2 or NT5E expression levels with the immunosuppressive functions of Tregs was analysed. In patients with SLE, the number of CD4⁺ IL2RA^- FOXP3⁺ T cell subset was positively correlated with the SLE disease activity index value and negatively correlated with the AHR and TET2 expression levels in CD4⁺ IL2RA⁺ FOXP3⁺ Tregs. Transcriptional profiles of 79 patients with SLE obtained from the Gene Expression Omnibus database (GSE61635 dataset) revealed a significant positive correlation between the mRNA expression levels of AHR and TET2. In silico analysis predicted that the TET2 promoter comprises an AHR-binding site. Kynurenine (KYN) promoted the binding of AHR to the TET2 promoter in Tregs of patients with SLE and Jurkat T cell lines. Furthermore, NT5E expression was significantly downregulated in Tregs of patients with SLE, which can be attributed to the dysregulation of NT5E promoter methylation status induced by downregulated TET2 activity. Furthermore, the Treg immunosuppressive activity, which is mediated through the TET2 and A2AR-adenosine pathways, in the KYN-treated group was approximately two-fold higher than that in the control group. The AHR/TET2/NT5E axis mediates the Treg immunosuppressive activity. These findings provide novel insights for the development of therapeutic approaches for SLE and related autoimmune diseases.

IFN-γ, should not be ignored in SLE

Systemic lupus erythematosus (SLE) is a typical autoimmune disease with a complex pathogenesis and genetic predisposition. With continued understanding of this disease, it was found that SLE is related to the interferon gene signature. Most studies have emphasized the important role of IFN-α in SLE, but our previous study suggested a nonnegligible role of IFN-γ in SLE. Some scholars previously found that IFN-γ is abnormally elevated as early as before the classification of SLE and before the emergence of autoantibodies and IFN-α. Due to the large overlap between IFN-α and IFN-γ, SLE is mostly characterized by expression of the IFN-α gene after onset. Therefore, the role of IFN-γ in SLE may be underestimated. This article mainly reviews the role of IFN-γ in SLE and focuses on the nonnegligible role of IFN-γ in SLE to gain a more comprehensive understanding of the disease.

SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target

Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.

Cryo-EM structure of SARS-CoV-2 ORF3a in lipid nanodiscs

SARS-CoV-2 ORF3a is a putative viral ion channel implicated in autophagy inhibition, inflammasome activation and apoptosis. 3a protein and anti-3a antibodies are found in infected patient tissues and plasma. Deletion of 3a in SARS-CoV-1 reduces viral titer and morbidity in mice, suggesting it could be an effective target for vaccines or therapeutics. Here, we present structures of SARS-CoV-2 3a determined by cryo-EM to 2.1-Å resolution. 3a adopts a new fold with a polar cavity that opens to the cytosol and membrane through separate water- and lipid-filled openings. Hydrophilic grooves along outer helices could form ion-conduction paths. Using electrophysiology and fluorescent ion imaging of 3a-reconstituted liposomes, we observe Ca²⁺-permeable, nonselective cation channel activity, identify mutations that alter ion permeability and discover polycationic inhibitors of 3a activity. 3a-like proteins are found across coronavirus lineages that infect bats and humans, suggesting that 3a-targeted approaches could treat COVID-19 and other coronavirus diseases.

Amino acid arginine and adducts: autoimmune activity

Arginine is derived from dietary intake, body protein breakdown, or endogenous de novo arginine production. Arginine methylation of non-histone proteins is used in transcriptional regulation. Protein-arginine methylation is used for regulation of transcriptional and various physiological pathological processes. Protein methylation may affect protein-protein, protein-DNA, or protein-RNA interaction. Arginine has an effect on the DNA-binding activity of NF-κB, a dominant transcriptional factor in inflammation. Adduct formation results in increased secretion of messenger molecules such as cytokines and chemokines that mediate communication among cells and promote inflammation. Arginine and lysine amino acid-rich histones in nucleosomes on modification by environmental agents form histone-DNA adducts, making it immunogenic. Alteration of DNA resulting from photomodification could lead to the development of antibodies or mutations to modified DNA. Lysine and arginine-rich histones in nucleosomes on modification by environmental agents form histone-DNA adducts, making it immunogenic. Alteration of DNA resulting from photomodification could lead to the development of antibodies or mutations to modified DNA. Therefore, the DNA-arginine photoadduct and modified photoadduct could have important implications in various pathophysiological conditions such as toxicology, carcinogenesis, and autoimmune phenomena. Abbreviations: Arg: Arginine; SLE: systemic lupus erythematosus; UV: ultraviolet; Tm: thermal melting temperature; NO: nitric oxide; O₂.^-: superoxide anion.

Aberrant T Cell Signaling and Subsets in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multi-organ debilitating autoimmune disease, which mainly afflicts women in the reproductive years. A complex interaction of genetics, environmental factors and hormones result in the breakdown of immune tolerance to "self" leading to damage and destruction of multiple organs, such as the skin, joints, kidneys, heart and brain. Both innate and adaptive immune systems are critically involved in the misguided immune response against self-antigens. Dendritic cells, neutrophils, and innate lymphoid cells are important in initiating antigen presentation and propagating inflammation at lymphoid and peripheral tissue sites. Autoantibodies produced by B lymphocytes and immune complex deposition in vital organs contribute to tissue damage. T lymphocytes are increasingly being recognized as key contributors to disease pathogenesis. CD4 T follicular helper cells enable autoantibody production, inflammatory Th17 subsets promote inflammation, while defects in regulatory T cells lead to unchecked immune responses. A better understanding of the molecular defects including signaling events and gene regulation underlying the dysfunctional T cells in SLE is necessary to pave the path for better management, therapy, and perhaps prevention of this complex disease. In this review, we focus on the aberrations in T cell signaling in SLE and highlight therapeutic advances in this field.

Parasites alter the pathological phenotype of lupus nephritis

lpr

Lupus nephritis is one of the most serious complications of systemic lupus erythematosus and manifests with considerable phenotypic and histological heterogeneity. In particular, diffuse proliferative lupus nephritis (DPLN) and membranous lupus nephritis (MLN) represent morphologic forms that are polar opposites. DPLN is associated with autoimmune responses dominated by Th1 immune response associated with high levels of interferon (IFN)-γ. In contrast, a Th2 cytokine response is associated with the pathogenesis of MLN. MRL/lpr mice develop human LN-like immune complex-associated nephritis and provide a suitable histological model for human DPLN. Infection with Schistosoma mansoni skewed a Th2-type immune response induction and IL-10 in MRL/lpr mice, drastically changing the pathophysiology of glomerulonephritis from DPLN to MLN accompanied by increased IgG1 and IgE in the sera. T cells in 32-week-old MRL/lpr mice infected with S. mansoni expressed significantly more IL-4 and IL-10 than T cells of uninfected mice; T cells with IFN-γ were comparable between infected and uninfected MR/lpr mice. Thus, the helminthic infection modified the cytokine microenvironment and altered the pathological phenotype of autoimmune nephritis.

Inhibition of PI3Kδ reduces kidney infiltration by macrophages and ameliorates systemic lupus in the mouse

Systemic lupus erythematosus (SLE) is a human chronic inflammatory disease generated and maintained throughout life by autoreactive T and B cells. Class I phosphoinositide 3-kinases (PI3K) are heterodimers composed of a regulatory and a catalytic subunit that catalyze phosphoinositide-3,4,5-P3 formation and regulate cell survival, migration, and division. Activity of the PI3Kδ isoform is enhanced in human SLE patient PBLs. In this study, we analyzed the effect of inhibiting PI3Kδ in MRL/lpr mice, a model of human SLE. We found that PI3Kδ inhibition ameliorated lupus progression. Treatment of these mice with a PI3Kδ inhibitor reduced the excessive numbers of CD4(+) effector/memory cells and B cells. In addition, this treatment reduced serum TNF-α levels and the number of macrophages infiltrating the kidney. Expression of inactive PI3Kδ, but not deletion of the other hematopoietic isoform PI3Kγ, reduced the ability of macrophages to cross the basement membrane, a process required to infiltrate the kidney, explaining MRL/lpr mice improvement by pharmacologic inhibition of PI3Kδ. The observations that p110δ inhibitor prolonged mouse life span, reduced disease symptoms, and showed no obvious secondary effects indicates that PI3Kδ is a promising target for SLE.

Overexpression of Epstein-Barr virus-induced gene 3 protein (EBI3) in MRL/lpr mice suppresses their lupus nephritis by activating regulatory T cells

To identify the effect of an imbalance of Th1/Th2 cytokines on the development of autoimmune glomerulonephritis (lupus nephritis), we studied the modification of pathological changes in diffuse proliferative glomerulonephritis (DPGN) and membranous glomerulonephritis (MGN) in MRL/lpr mice, which are animal models of systemic lupus erythematosus (SLE). Transgenic MRL/lpr mice (Tg) that overexpressed Epstein--Barr virus-induced gene 3 (EBI3) showed almost normal renal function, which was demonstrated by healing of glomerulonephritis upon renal histology, as compared to the wild-type MRL/lpr (Wt) mice. The levels of anti-dsDNA antibodies and IgE decreased in the Tg mice compared to Wt mice. Quantitative real-time PCR indicated an increase in the mRNA levels of FoxP3, and a decrease in that of IFNγ in the splenocytes of Tg mice as compared to Wt mice. In addition, flow cytometric analysis showed an increase in CD4(+)CD25(+)FoxP3(+)-T cells in the former, as compared to the latter. Our findings suggest that EBI3-overexpression in MRL/lpr mice induces generation of regulatory T cells, which causes suppression of autoimmune and inflammatory reactions by affecting the Th1/Th2 cytokine balance.

Therapeutic strategies for SLE involving cytokines: mechanism-oriented therapies especially IFN-gamma targeting gene therapy

Systemic lupus erythematosus (SLE: lupus) is a chronic complicated autoimmune disease and pathogenesis is still unclear. However, key cytokines have been recognized. Interferon (IFN)-γ and also IFNalpha/beta are of particular importance. Depending on the concept that lupus is a helper T(Th)1 disease and that dendritic cells (DCs) determine the direction of lupus, balance shift of Th1/Th2 and immunogenic/tolerogenic DCs is reviewed for therapy. (IFN)-gamma- and IFN-alpha/beta-targeted (gene) therapies are introduced. These consist of Th1/Th2 balance shift and elimination of IFN-gamma and IFN-gamma-related cytokines such as (interleukin)IL-12 and IL-18. Other approaches include suppression of immunocompetent cells, normalization of abnormal T-cell function, costimulation blockade, B lymphocyte stimulator (Blys) blockade, and suppression of nephritic kidney inflammation. Moreover, balance shift of IFN-alpha/beta and tumor necrosis factor (TNF)-alpha together with regulatory T(Treg) cells are briefly introduced. Clinical application will be discussed.

Overexpression of interferon-activated gene 202 (Ifi202) correlates with the progression of autoimmune glomerulonephritis associated with the MRL chromosome 1

B6.MRLc1(82-100) congenic mice carrying the telomeric region of lupus-prone MRL chromosome 1 develop autoimmune glomerulonephritis (GN). The GN susceptibility locus of B6.MRLc1(82-100) contains the interferon activated gene 200 (Ifi200) family, which consists of Ifi202, 203, 204, and 205. Recently, Ifi202 was suggested as a candidate gene for murine lupus. In this study, we assessed the association between Ifi200 family and GN in several disease models. We compared the expression of Ifi200 family members in 24 organs between the C57BL/6 and B6.MRLc1(82-100). The expressions of Ifi200 family members differed between strains, and the most dramatic differences appeared in Ifi202 expression. Briefly, in the blood, immune organs, lungs, and testes mRNA expression was higher in B6.MRLc1(82-100) mice. In the kidney and immune organs, only Ifi202 expression increased with the development of GN in B6.MRLc1(82-100), and significant differences from C57BL/6 were observed even before disease onset. Ifi202 expression in the kidneys of BXSB, NZB/WF1, and MRL/lpr was also significantly high in the early- and late-disease stages. Furthermore, laser microdissection-reverse-transcriptase-polymerase chain reaction analysis confirmed the high Ifi202 expression in all areas of B6.MRLc1(82-100) kidneys. In conclusion, in the Ifi200 family, Ifi202 expressions in the kidney and immune organs significantly increased with GN progression.

Therapeutic applications and mechanisms underlying the activity of immunosuppressive oligonucleotides

Synthetic oligodeoxynucleotides (ODN) capable of "neutralizing" or "inhibiting" immune responses have been described. This review will focus on the properties of phosphorothioate ODN that mimic the immunosuppressive activity of the repetitive TTAGGG motifs present in mammalian telomeres. These TTAGGG multimers block the production of pro-inflammatory and T helper type 1 cytokines elicited when immune cells are activated by a wide variety of Toll-like receptor ligands, polyclonal activators, and antigens. Several mechanisms contribute to the suppressive activity of such ODN. Ongoing microarray studies indicate that suppressive ODN interfere with the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT4, thereby blocking the inflammation mediated by STAT-associated signaling cascades. In animal models, suppressive ODN can be used to prevent or treat diseases characterized by persistent immune activation, including collagen-induced arthritis, inflammatory arthritis, systemic lupus erythematosus, silicosis, and toxic shock. These findings suggest that TTAGGG multimers may find broad use in the treatment of diseases characterized by over-exuberant/persistent immune activation.

Association of estrogen receptor alpha gene polymorphisms with cytokine genes expression in systemic lupus erythematosus

AIM

To analyze the association of estrogen receptor alpha (OR alpha) gene polymorphisms with cytokine genes expression in patients with systemic lupus erythematosus (SLE) and controls.

METHODS

Genomic DNA was extracted and polymorphisms of XbaI, Ukrainian (XX, Xx, or xx genotype) and PvuII (PP, Pp, or pp) in intron 1 of OR alpha gene were detected by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method. The messenger RNA (mRNA) levels of interleukin (IL)-10, IL-4, interferon (IFN)-gamma, and IL-2 were assessed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

In patients with SLE with PpXx genotype, IL-10 and IL-4 mRNA expression was higher (P < 0.001 and P = 0.013, respectively), while in patients with SLE with Ppxx genotype IFN-gamma and IL-2 mRNA expression was lower than in controls (P < 0.001). There was no significant difference in mRNA expression of 4 cytokines among controls with various genotypes.

CONCLUSION

OR alpha gene polymorphism may be associated with the expression of IL-10, IL-4, IL-2, and IFN-gamma in patients with SLE.

P2X7 gene polymorphisms do not appear to be a susceptibility gene locus in sporadic cases of systemic lupus erythematosus

The P2X(7) receptor is a ligand-gated cation-selective channel that mediates ATP-induced apoptosis of cells of the immune system. A loss-of-function single nucleotide polymorphism (SNP) at position 1513 (1513 A-->C) of the P2X(7) gene has recently been identified in both healthy and chronic lymphocytic leukemia (CLL) B-cells, translating into a loss of P2X(7)-mediated apoptosis in these cells. This antiapoptotic effect results in increased B-cell numbers, thereby potentially contributing to the survival of B-CLL clones. It was hypothesized that prolonged cell survival may also predispose to induction of autoimmunity. The objective of this study is to analyze the role of the P2X(7) receptor and its loss-of-function 1513 A-->C polymorphism (SNP) in the development of systemic lupus erythematosus (SLE). DNA samples obtained from patients with sporadic SLE were analyzed for the presence of the 1513 A-->C polymorphism using polymerase chain reaction (PCR) amplification and then direct sequencing. No significant difference in allele frequencies (1513 A-->C polymorphism) between sporadic cases of SLE and controls was found. A loss-of-function SNP at position 1513 (1513 A-->C) of the P2X(7) gene does not appear to be a susceptibility gene locus for the development of sporadic SLE.

Lymphocytes with aberrant expression of Fas or Fas ligand attenuate immune bone marrow failure in a mouse model

Bone marrow (BM) and lymphocyte samples from aplastic anemia patients show up-regulated Fas and Fas-ligand (FasL) expression, respectively, supporting a relationship between immune-mediated BM destruction and the Fas apoptotic pathway. Mice with spontaneous lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld) mutations exhibit abnormal expression of Fas and FasL, serving as potential models to elucidate underlying mechanisms of BM failure. We examined cellular and functional characteristics of lpr and gld mutants on the C57BL/6 (B6) background. Lymph node (LN) cells from lpr and gld mice produced less apoptosis when coincubated with C.B10-H2(b)/LilMcd (C.B10) BM cells in vitro. This functional difference was confirmed by infusing lpr, gld, and B6 LN cells into sublethally irradiated CB10 mice. All donor LN cells showed significant T cell expansion and activation, but only B6 LN cells caused severe BM destruction. Mice infused with gld LN cells developed mild to moderate BM failure despite receiving FasL-deficient effectors, thus suggesting the existence of alternative pathways or incomplete penetrance of the mutation. Paradoxically, mice that received Fas-deficient lpr LN cells also had reduced BM failure, likely due to down-regulation of proapoptotic genes, an effect that can be overcome by higher doses of lpr LN cells. Our model demonstrates that abnormal Fas or FasL expression interferes with the development of pancytopenia and marrow hypoplasia, validating a major role for the Fas/FasL cytotoxic pathway in immune-mediated BM failure, although disruption of this pathway does not completely abolish marrow destruction.

[Two faces of Janus. Coexistence of systemic lupus erythematosus and psoriasis in the same patient]

While both lupus erythematosus and psoriasis are inflammatory dermatoses characterized by scaly erythematous plaques, they are rarely confused in clinical practice. We report a woman who alternately presented with lupus erythematosus and psoriasis over 14 years but the former condition was not recognized and adequately treated. After the complete diagnosis had been established, a combination of thalidomide and acitretin resulted in a prolonged remission of both disorders. This unusual case demonstrates that coexistence of two diseases in one patient presents a diagnostic challenge that can only be met by repeated careful correlation of all clinical and histopathologic findings. It is of particular importance if these diseases require conflicting management strategies.

Severe tissue trauma triggers the autoimmune state systemic lupus erythematosus in the MRL/++ lupus-prone mouse

Tissue damage associated with a severe injury can result in profound inflammatory responses that may trigger autoimmune development in lupus-prone individuals. In this study, we investigated the role of a large full-thickness cutaneous burn injury on the early onset of autoimmune disease in lupus-prone MRL/++ mice. MRL/++ mice (chronic model) exhibit autoimmune symptoms at >70 weeks of age, whereas MRL/-Faslpr mice (acute model) develop autoimmune disease in 17–22 weeks due to a lymphoproliferative mutation. Autoimmune disease developed in MRL/++ mice (4–15 weeks post injury) is manifested by skin lesions, vasculitis, epidermal ulcers, cellular infiltration, splenomegaly, lymphadenopathy, hypergammaglobulinemia, elevated autoantibodies and renal pathologies including proteinuria, glomerulonephritis and immune complex deposition; complications that contribute to reduced survival. Transcription studies of wound margin tissue show a correlation between the pathogenic effects of dysregulated IL-1β, IL-6, TNF-α and PGE2 synthesis during early wound healing and early onset of autoimmune disease. Interestingly, MRL/++ mice with healed wounds (30–40 days post burn) strongly rejected skin isografts. Conversely, skin isografts transplanted onto naive age-matched MRL/++ littermates achieved long-term survival. Collectively, these findings suggest that traumatic injury exacerbates inflammatory skin disease and severe multi-organ pathogenesis in lupus-prone mice.

Elevated expression of transmembrane IL-15 in immune cells correlates with the development of murine lupus: a potential target for immunotherapy against SLE

Presentation in trans by the Interleukin-15 receptor alpha chain (IL-15Ralpha) has been suggested as the main mechanism for IL-15 anchoring to the cell surface, but it is also evident that IL-15 can exist as a transmembrane protein. We herein demonstrate that replacement of the first 41 residues of human IL-15 (hIL-15) with Igkappa chain leader sequence resulted in secretion of most of the recombinant hIL-15 expressed in transfectant cells, thus identifying the transmembrane region of IL-15. A fusion protein (hIL-15Ralpha-Fc) between the extracellular domain of hIL-15Ralpha and the Fc fragment of IgG1 was prepared and shown to be able to bind with transmembrane IL-15 (tmIL-15). The level of tmIL-15 expression in macrophages, activated T cells and B cells from 6-month-old BXSB male mice, an animal model for systemic lupus erythematosus (SLE), was significantly increased compared with that from BXSB females or young males. In addition, hIL-15Ralpha-Fc was able to block the T cell stimulating and anti-apoptotic effect of the tmIL-15-positive BXSB macrophages in vitro. Intravenous administration of hIL-15Ralpha-Fc reduced the titre of autoantibodies against dsDNA and also proteinuria in aged BXSB males, implying that neutralization of IL-15 activity in vivo may be an effective way of treating SLE.

Mechanisms behind flare of renal lupus during murine pregnancy

The outcome of pregnancy in systemic lupus erythematosus is still controversial. The authors recently reported the disappearance of the manifestation of the skin disease but a diminished survival rate in lupus-prone animals undergoing several pregnancies. It was postulated that lupus-prone animals must have subclinical renal symptoms at an early age and that immune and hormonal changes during pregnancy exacerbate immune reactions in the kidneys, leading to a shortened life span. Here, the authors analysed changes at day 14 of pregnancy in lupus-prone LPR (MRL/lpr) mice and MRL controls regarding cytokines, regulatory T (Treg) cells and deposition of immunocomplexes. Worsened kidney function was observed during pregnancy, even in the absence of lupus signs. This was accompanied by renal inflammation and higher interferon-gamma and interleukin-10 levels. C3 and immunoglobulin G deposition was enhanced in kidney and placenta from lupus-prone pregnant animals. Pregnancy enhanced the levels of Treg cells in control animals but not in lupus-prone animals. As pregnancy-induced Treg cells were shown to be specific for paternal antigens it is not to be expected that these Treg cells can help to destroy autoreactive cells. The authors conclude that early subclinical kidney disease in lupus-prone animals exacerbates during pregnancy. Albeit obtained with an experimental animal model, their data are potentially of importance for lupus patients of reproductive age.

The proteasome inhibitor bortezomib depletes plasma cells and protects mice with lupus-like disease from nephritis

Autoantibody-mediated diseases like myasthenia gravis, autoimmune hemolytic anemia and systemic lupus erythematosus represent a therapeutic challenge. In particular, long-lived plasma cells producing autoantibodies resist current therapeutic and experimental approaches. Recently, we showed that the sensitivity of myeloma cells toward proteasome inhibitors directly correlates with their immunoglobulin synthesis rates. Therefore, we hypothesized that normal plasma cells are also hypersensitive to proteasome inhibition owing to their extremely high amount of protein biosynthesis. Here we show that the proteasome inhibitor bortezomib, which is approved for the treatment of multiple myeloma, eliminates both short- and long-lived plasma cells by activation of the terminal unfolded protein response. Treatment with bortezomib depleted plasma cells producing antibodies to double-stranded DNA, eliminated autoantibody production, ameliorated glomerulonephritis and prolonged survival of two mouse strains with lupus-like disease, NZB/W F1 and MRL/lpr mice. Hence, the elimination of autoreactive plasma cells by proteasome inhibitors might represent a new treatment strategy for antibody-mediated diseases.

Synthetic oligonucleotides as modulators of inflammation

Synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs mimic the immunostimulatory activity of bacterial DNA. CpG ODN directly stimulate human B cells and plasmacytoid dendritic cells, promote the production of Th1 and proinflammatory cytokines, and trigger the maturation/activation of professional APC. CpG ODN are finding use in the treatment of cancer, allergy, and infection. In contrast, ODN containing multiple TTAGGG motifs mimic the immunosuppressive activity of self-DNA, down-regulating the production of proinflammatory and Th1 cytokines. Preclinical studies suggest that "suppressive" ODN may slow or prevent diseases characterized by pathologic immune stimulation, including autoimmunity and septic shock. Extensive studies in animal models suggest that the therapeutic value of CpG and TTAGGG ODN may be optimized by early administration.

Apoptosis of murine lupus T cells induced by the selective cyclooxygenase-2 inhibitor celecoxib: Molecular mechanisms and therapeutic potential

Upregulation of cyclooxygenase (COX)-2 in T cells from patients with systemic lupus erythematosus (SLE) is associated with their resistance to functional inactivation (anergy) and to activation-induced cell death through apoptosis. It has been demonstrated that celecoxib, a selective COX-2 inhibitor, can enhance apoptosis of human lupus T cells. The present study was undertaken to investigate whether COX-2 expression is also upregulated in T cells from the lupus-prone BXBS strain of mice and if murine lupus is modified by celecoxib. COX-2 expression was detected in splenic T cells from 6 month-old male BXSB mice (murine lupus T cells) but not in T cells from 2 month-old male or 6-month-old female BXSB or in 6-month-old male C57BL/6 mice, indicating a strong correlation between COX-2 expression in T cells and lupus manifestation in mice. Celecoxib treatment induced apoptosis of murine lupus T cells in vitro, which was inhibited by z-VAD-fmk, a pan-caspase inhibitor. In the murine lupus T cells treated with celecoxib, procaspases 3 and 9, but not procaspase 8, were activated. In addition, celecoxib treatment decreased the mitochondrial membrane potential of murine lupus T cells. These data combine to suggest that celecoxib mainly uses the mitochondrial pathway rather than FADD pathway to trigger apoptosis of COX-2 expressing murine lupus T cells. Intragastric administration of celecoxib (40 mg/kg/day for 60 days) in 6-month-old male BXSB mice effectively limited the production of serum antibodies against dsDNA. Our data suggest that celecoxib may have a beneficial effect in treating autoimmune diseases such as SLE through inducing apoptosis of autoreactive T cells.

Activation of the signal transducer and activator of transcription-1 in diffuse proliferative lupus nephritis

Difuse proliferative lupus nephritis (DPLN) is the most common and severe form of lupus nephritis. A predominance of IFN-gamma-producing T cells in both peripheral and renal tissues of patients with DPLN has been identified which suggests an important role for cell-mediated immunity in the pathogenesis of this complication in SLE. The biological effects of IFN-gamma rely mainly on the activity of the transcription factor called signal transducer and activator of transcription (STAT)-1. To assess the IFN-gamma/STAT-1 pathway in DPLN, we examined the expression of STAT-1 in renal biopsies from 15 DPLN patients by immunohistochemical staining with an anti-STAT-1 antibody. The expression of STAT-1 in renal tissues was correlated with several clinical and laboratory findings in these DNPN patients.STAT-1 was activated in the tubular cells in all DPLN patients. Seven of 15 DPLN biopsies (46.7%) showed positive cells in glomeruli. Five of these seven DPLN biopsies (71.4%) with positive glomerular cells showed a serum creatinine >1.5 mg/mL at the time the biopsy was carried out whereas only one of eight DPLN biopsy specimens (12.5%) without positive glomerular cells, showed a serum creatinine >1.5 mg/mL (P = 0.041). Moreover, the percentage of DPLN patients with a worse renal outcome in those who showed expression of STAT-1 in glomerulari were higher in comparison to those without STAT-1 expression (P = 0.041). Our results show that STAT-1 is activated in DPLN suggesting that biological effects of IFN-gamma in renal tissues depend, at least in part, on the activation of STAT-1.

Skin disease is prevented but nephritis is accelerated by multiple pregnancies in autoimmune MRL/LPR mice

The role of pregnancy in the progression of systemic lupus erythematosus (SLE) is still poorly understood. We analysed the effect of repeated pregnancies in MRL/lpr mice, a murine model of SLE. Seven-week old female mice were used: multiparous mice underwent three consecutive pregnancies (M); age-matched virgin mice served as controls (V). Animals were harvested at 20 weeks of age. Skin lesions were characterized by hair loss and scabs in the dorsum of the neck. Virgin skins showed thickened dermis, fibrosis and mononuclear cell infiltrates, which were practically absent in M. This was accompanied by higher IFN-gamma and lower IL-10 mRNA expression levels in V compared to M skin. Plasma IFN-gamma protein levels were also upregulated in V versus M. However, survival and kidney function were dramatically reduced and accompanied by hypertension after multiple pregnancies. Kidney histology also showed markedly increased renal lesions in M. In contrast to plasma and skin levels, both IL-10 and IFN-gamma mRNA were lower in the kidneys of V versus M mice. Concluding our findings, the pathomechanisms of lupus kidney and skin disease may be regulated differently at the organ level during pregnancy. Both IFN-gamma and IL-10 may be important regulatory cytokines at the local level.

Interaction between antigen presenting cells and autoreactive T cells derived from BXSB mice with murine lupus

Systemic lupus erythematosus (SLE) is a typical autoimmune disease involving multiple systems and organs. Ample evidence suggests that autoreactive T cells play a pivotal role in the development of this autoimmune disorder. This study was undertaken to investigate the mechanisms of interaction between antigen presenting cells (APCs) and an autoreactive T cell (ATL1) clone obtained from lupus-prone BXSB mice. ATL1 cells, either before or after gamma-ray irradiation, were able to activate naive B cells, as determined by B cell proliferation assays. Macrophages from BXSB mice were able to stimulate the proliferation of resting ATL1 cells at a responder/stimulator (R/S) ratio of 1/2.5. Dendritic cells (DCs) were much more powerful stimulators for ATL1 cells on a per cell basis. The T cell stimulating ability of macrophages and B cells, but not DCs, was sensitive to gamma-ray irradiation. Monoclonal antibodies against mouse MHC-II and CD4 were able to block DC-mediated stimulation of ATL1 proliferation, indicating cognate recognition between ATL1 and APCs. Our data suggest that positive feedback loops involving macrophages, B cells and autoreactive T cells may play a pivotal role in keeping the momentum of autoimmune responses leading to autoimmune diseases.

Membranous glomerulonephritis development with Th2-type immune deviations in MRL/lpr mice deficient for IL-27 receptor (WSX-1)

MRL/lpr mice develop spontaneous glomerulonephritis that is essentially identical with diffuse proliferative glomerulonephritis (World Health Organization class IV) in human lupus nephritis. Lupus nephritis is one of the most serious complications of systemic lupus erythematosus. Diffuse proliferative glomerulonephritis is associated with autoimmune responses dominated by Th1 cells producing high levels of IFN-gamma. The initial mounting of Th1 responses depends on the function of the WSX-1 gene, which encodes a subunit of the IL-27R with homology to IL-12R. In mice deficient for the WSX-1 gene, proper Th1 differentiation was impaired and abnormal Th2 skewing was observed during infection with some intracellular pathogens. Disruption of the WSX-1 gene dramatically changed the pathophysiology of glomerulonephritis developing in MRL/lpr mice. WSX-1-/- MRL/lpr mice developed disease resembling human membranous glomerulonephritis (World Health Organization class V) with a predominance of IgG1 in glomerular deposits, accompanied by increased IgG1 and IgE in the sera. T cells in WSX-1-/- MRL/lpr mice displayed significantly reduced IFN-gamma production along with elevated IL-4 expression. Loss of WSX-1 thus favors Th2-type autoimmune responses, suggesting that the Th1/Th2 balance may be a pivotal determinant of human lupus nephritis development.

Class IB-Phosphatidylinositol 3-Kinase (PI3K) Deficiency Ameliorates IA-PI3K-Induced Systemic Lupus but Not T Cell Invasion

Class I PI3K catalyzes formation of 3-poly-phosphoinositides. The family is divided into IA isoforms, activated by Tyr kinases and the IB isoform (PI3Kgamma), activated by G protein-coupled receptors. Mutations that affect PI3K are implicated in chronic inflammation, although the differential contribution of each isoform to pathology has not been elucidated. Enhanced activation of class IA-PI3K in T cells extends CD4+ memory cell survival, triggering an invasive lymphoproliferative disorder and systemic lupus. As both IA- and IB-PI3K isoforms regulate T cell activation, and activated pathogenic CD4+ memory cells are involved in triggering systemic lupus, we examined whether deletion of IB could reduce the pathological consequences of increased IA-PI3K activity. IB-PI3Kgamma deficiency did not abolish invasion or lymphoproliferation, but reduced CD4+ memory cell survival, autoantibody production, glomerulonephritis, and systemic lupus. Deletion of the IB-PI3Kgamma isoform thus decreased survival of pathogenic CD4+ memory cells, selectively inhibiting systemic lupus development. These results validate the PI3Kgamma isoform as a target for systemic lupus erythematosus treatment.

Suppressive oligodeoxynucleotides delay the onset of glomerulonephritis and prolong survival in lupus-prone NZB x NZW mice

OBJECTIVE

Synthetic oligodeoxynucleotides (ODN) expressing TTAGGG motifs suppress the production of proinflammatory cytokines and have been proven effective at blocking the development of certain organ-specific autoimmune diseases. We undertook this study to determine whether suppressive ODN alter the development of systemic autoimmunity, by evaluating their effect on the progression of lupus-like disease in NZB x NZW (NZB/NZW) mice.

METHODS

We repeatedly treated mice with suppressive ODN before or after the onset of proteinuria. We monitored the effect of treatment on the onset, severity, and immunologic correlates of disease.

RESULTS

Treatment with suppressive ODN significantly prolonged lifespan while delaying the onset and progression of glomerulonephritis in NZB/NZW mice. Clinical improvement was accompanied by a significant reduction in anti-double-stranded DNA autoantibody production and by significantly reduced secretion of interferon-gamma and interleukin-12 in vivo.

CONCLUSION

Suppressive ODN may be of benefit in the treatment of chronic systemic autoimmune diseases such as systemic lupus erythematosus.

Up-regulation of IL-18 and predominance of a Th1 immune response is a hallmark of lupus nephritis

There is evidence that nephritis is dominated by a Th1 immune response in systemic lupus erythematosus. Since IL-18 promotes polarization of the immune response toward Th1, we investigated the role of this cytokine in lupus nephritis (LN). A total of 133 lupus patients and 44 healthy subjects were enrolled. Demographic and clinical characteristics with renal biopsy data were recorded. IL-18 along with IFN-gamma and IL-4, two prototypical of Th1 and Th2 cytokines, were measured in serum by ELISA. Peripheral blood lymphocytes were analysed by flow cytometry for IFN-gamma and IL-4. IL-18 expression was determined by immunohistochemistry in 13 renal biopsy specimens from patients with LN and 2 controls. Serum IL-18 was higher in lupus patients than in controls. Levels of IL-18 correlated with urinary microalbumin and were increased in patients with LN when compared to those without LN. IL-18 expression was also increased within the glomeruli of nephritic patients and was primarily detected within the mesangial matrix and in infiltrating mononuclear cells. Measurement of IFN-gamma and IL-4 in either sera or peripheral blood lymphocytes showed high IFN-gamma along with low IL-4 expression in LN patients compared to patients without nephritis. A positive correlation between serum IL-18 and IFN-gamma levels was found. IL-18 may play a prominent role in the pathogenesis of LN by promoting a cytokine imbalance towards a Th1 immune response. Measurement of IL-18 may be helpful for the early identification of lupus patients with LN and may help gauge the response to treatment in patients with active LN undergoing treatment.

Aberration of CCR7 CD8 memory T cells from patients with systemic lupus erythematosus: an inducer of T helper type 2 bias of CD4 T cells

Chemokine receptors are important in the entry of leucocytes into the inflammatory sites of systemic lupus erythematosus (SLE). CCR7(+) and CCR7(-) memory T cells exert different functions in homing, cytokine production and cytotoxicity. To determine whether differential expression and functions of the CCR7 occur in SLE patients, we examined CCR3, CCR4, CCR5, CCR7 and CCR9 on CD4(+) and CD8(+) T cells from normal and SLE subjects. Flow cytometry, real-time quantitative reverse transcription polymerase chain reactions and Northern blotting were used to detect the expression of chemokine receptors and cytokines; a chemotaxis assay was used to detect their functions. CD4(+) T-cell stimulation with syngeneic CCR7(+) CD8(+) CD45RO(+) T cells and dendritic cells (including transwell chambers) was used to induce cytokine expression. We demonstrated that CCR7 was selectively, frequently and functionally expressed on CD8(+) (94.8%) but not on CD4(+) (16.1%) T cells from patients with active SLE, whereas this phenomenon was not seen in normal subjects and in those whose SLE was inactive. CCR7(+) CD8(+) CD45RO(+) memory T cells from patients with active SLE, themselves T helper type 2 (Th2) biased, were inducers of Th2 bias in CD4(+) T cells in a cell-cell contact manner in vitro, meanwhile, the cells from both normal subjects and those whose SLE was inactive drove CD4(+) T cells into a regulatory T-cell-derived cytokine pattern. Our findings might provide new clues to understanding the functions of CCR7(+) CD8(+) CD45RO(+)'central' memory T cells in autoimmune diseases (such as SLE). We suggest that in the case of active SLE, CCR7(+) central memory T cells were able to enter peripheral blood and inflammatory sites from secondary lymphoid organs, were continuously expressing CCR7, and interacted with dendritic cells and functioned as CCR7(-)'effector' memory T cells, which were described in normal humans.

Nonmyeloablative Bone Marrow Transplantation of BXSB Lupus Mice Using Fully Matched Allogeneic Donor Cells from Green Fluorescent Protein Transgenic Mice

Male BXSB mice, a mouse model of systemic lupus erythematosus, were given bone marrow transplants (BMT) at 20 wk of age using MHC-matched donor cells and nonmyeloablative conditioning (550 cGy irradiation). Transplanted mice and irradiation controls were followed for a period of 20 wk. Mice transgenic for green fluorescent protein were used as donors to allow tracking of donor cells and a determination of chimerism. Radiation controls had reduced renal pathology at 10 wk posttransplant, but not at 20 wk compared with untreated mice, while nonmyeloablative BMT mice had significantly reduced pathology at both time intervals. The monocytosis characteristic of older BXSB mice was also reduced by BMT, but the treatment did not prevent production of Ab to dsDNA. A stable chimerism of 24-40% donor CD45-positive cells was achieved in spleen and bone marrow, and there was no evidence of clinical graft vs host disease. Donor cells were detected in most recipient organs, notably the thymus and renal glomeruli. The results suggest that complete depletion of mature lymphocytes or of progenitor stem cells is not required to control lupus nephritis in BXSB mice.

Uncovering the genetics of systemic lupus erythematosus: implications for therapy

Although it is well known that genetic factors contribute significantly to the expression of systemic lupus erythematosus (SLE) it was only recently realized, through genome-wide searches, that the number of involved genes is rather large. The published information hints at two facts: first, the number of genomic loci identified in various diverse cohorts is large and not necessarily overlapping; and second, certain loci may be preferentially linked with specific clinical manifestations. The latter may ultimately lead to a better understanding of the nature of the clinical entity that we know as SLE, and identification of groups of patients prone to respond better to treatment or to develop significant adverse effects. Advances attained regarding the nature of the biochemical and molecular defects that underwrite the aberrant function of immune cells parallel the progress made on the genetic origin of the disease. The genetic links need to be connected with aberrant function of their products to validate their significance. It is expected that correction of molecular aberrations either medicinally or by gene therapy will provide the needed specific treatment for patients with SLE.

Assessment of Be1 and Be2 cells in systemic lupus erythematosus indicates elevated interleukin-10 producing CD5+ B cells

Recent studies indicate that normal B cells can be primed to differentiate into two distinct cytokine-secreting effector subsets, Be1 and Be2. The aim of this study was to analyse, for the first time, Be1 and Be2 cells at the single cell level in SLE patients using the recently developed technique of flow cytometry for intracellular cytokines. Peripheral blood mononuclear cells (PBMC) from SLE patients and age- and sex-matched normal controls were cultured for 24 h in the presence or absence of phorbal myristate acetate and ionomycin (PMA/I) or lipopolysaccharide (LPS). The production of type I (IFN-gamma, IL-2) and type 2 (IL-4, IL-5, IL-6, IL-10, IL-13) cytokines by B cells (and IL-10 production by fractionated CD5+ and CD5- B cells) was investigated using an intracellular cytokine staining technique and flow cytometry. In the absence of PMA/I stimulation, the percentage of B cells from SLE patients was significantly lower than those of normal subjects and significantly more SLE B cells spontaneously produced IL-10 than controls. Moreover, CD5+ B cells from SLE patients were enriched for cells with signs of previous in vivo activation and for high levels of IL-10 production. A significant positive correlation was observed between the percentage of IL-10- and IL-6-producing PMA/I-stimulated B cells in SLE patients, but not in controls. There were no significant differences in the production of other cytokines by B cells of SLE patients and normal subjects. In conclusion, a general alteration of type 1 and type 2 cytokine production by B cells is not observed in SLE patients. The role of B cell cytokines in the pathogenesis of SLE appears to be exerted by elevated secretion of in vivo IL-10, which may play an important role in the immune dysregulation observed in SLE patients. Moreover, the cross regulation of IL-10 and IL-6 is disrupted in SLE patients.

A patient with a Mycobacterium avium complex infection complicated by systemic lupus erythematosus

A 41-year-old woman was admitted to our hospital because of fever and polyarthralgia. A diagnosis of systemic lupus erythematosus (SLE) was made based on the findings of polyarthritis, leukocytopenia, lymphocytopenia, proteinuria, and positive reactions for antinuclear antibody (ANA) and anti-double strand (ds)DNA antibody. She had also been suffering from a pulmonary Mycobacterium avium complex (MAC) infection with such symptoms as cough and sputum for the past 3 years. Antimicrobial drugs for MAC infection were administered first, and later she was given cyclophosphamide pulse therapy, consisting of methylprednisolone (8 mg/day) and mizoribine (100 mg/day). Owing to these therapeutic regimens, SLE was successfully treated without an exacerbation of the MAC infection. The risk factors for MAC infection and SLE are also discussed.

Polydeoxyribonucleotide C photoconjugated with lysine or arginine present unique epitopes for human anti-DNA autoantibodies

Studies have been carried out to synthesize and characterize the photoconjugates between positively charged amino acids (lysine and arginine) and the polydeoxyribonucleotide C [poly(dC)]. Poly(dC) was covalently crosslinked with lysine or arginine under ultraviolet light. Both lysine and arginine were found covalently photoconjugated to poly(dC), resulting in the formation of photoadduct. Photoaddition of lysine or arginine to poly(dC) rendered them thermodynamically more stable than their native form. A strong recognition of photoadducts was observed with anti-DNA autoantobodies found in the sera of systemic lupus erythematosus (SLE) patients. Poly(dC)-lysine was recognized more strongly than poly(dC)-argine photoadduct. Poly(dC)-lysine photoadduct appears to provide an immunodominant epitope for SLE autoantibody recognition. The result suggests for the possible involvement of these photoadducts as a potential trigger for anti-DNA autoantibody production.

Regulation of CCR5 expression and MIP-1alpha production in CD4+ T cells from patients with rheumatoid arthritis

Production of CCR5 expression and MIP-1alpha, a ligand of CCR5, by CD4+ T cells from patients with rheumatoid arthritis (RA) were studied. We analysed further the influence of IL-15 stimulation, CD40/CD40 ligand (CD40L) interaction and CCR5 promotor polymorphism. One hundred and fifty-five RA patients and another 155 age- and sex-matched healthy individuals were enrolled. Peripheral CD4+ and double negative (DN) T cells from patients had lower portions of CCR5, whereas synovial CD4+ and DN T cells showed a much higher CCR5 expression. IL-15 significantly up-regulated the expression of CCR5 on purified CD4+ T cells. CD40L expression on synovial CD4+ T cells was increased greatly in CCR5+ portions by IL-15. MIP-1alpha production by synovial CD4+ T cells was also enhanced by IL-15. Co-culture of CD40 expressing synovial fibroblasts with IL-15-activated synovial CD4+ T cells significantly increased MIP-1alpha production. Expression of CCR5 on patients' CD4+ T cells was not influenced by the promotor polymorphism of CCR5 gene. Taken together, these data suggest CCR5+CD4+ T cells infiltrate the inflamed synovium and IL-15 up-regulates CCR5 and CD40L expression further and enhance MIP-1alpha production in synovial CD4+ T cells. Production of MIP-1alpha by synovial fibroblasts is significantly increased by engagement of CD40 with CD40L. Synovial microenvironment plays a potential role in regulation of CCR5+CD4+ T cells in rheumatoid joints.

Oxygen free radicals and systemic autoimmunity

Reactive oxygen species generated during various metabolic and biochemical reactions have multifarious effects that include oxidative damage to DNA leading to various human degenerative and autoimmune diseases. The highly reactive hydroxy radical (*OH) can interact with chromatin and result in a wide range of sugar and base-derived products, DNA-protein cross-links and strand breaks. Studies from our laboratory have demonstrated that after modification the DNA becomes highly immunogenic and the induced antibodies exhibit variable antigen-binding characteristics. Systemic lupus erythematosus, a prototype autoimmune disease, is characterized by the presence of autoantibodies to multiple nuclear antigens. The detection of 8-hydroxyguanosine in the immune complex derived DNA of systemic lupus erythematosus patients reinforces the evidence that reactive oxygen species may be involved in its pathogenesis. Increased apoptosis and decreased clearance of apoptotic cells as observed in systemic lupus erythematosus (SLE) might well be a contributory factor in systemic autoimmunity. Clinically, titres of autoantibodies are closely related to the degree of renal inflammation. Anti-DNA antibodies may combine with circulating antigen and contribute to the deposition of immune complexes in renal glomeruli.

Isolation and functional analysis of autoreactive T cells from BXSB mice with murine lupus

CD4(+) T helper cells play a pivotal role in the pathogenesis of SLE, although the mechanism is still unclear. The present study was designed to isolate and characterize autoreactive T lymphocytes from BXSB mice, a mouse model for human SLE. Splenocytes from 6-month-old male BXSB mice with murine lupus were repeatedly stimulated in vitro with irradiated syngeneic B cells in the presence of recombinant IL-2, resulting in six autoreactive T-cell lines and two T-cell clones. TCR analysis showed that, one of the T-cell lines, ATL1, was almost clonal, as a Vbeta2.1-Jbeta2, a Valpha5.1-Jalpha15 and a Valpha10.1-Jalpha15 chains were predominantly expressed in this line. The two clones derived from ATL1 turned out to be sister clones, using the TCR Vbeta2.1-Jbeta2 and Valpha10.1-Jalpha15 chains. ATL1 cells proliferated in response to stimulation of syngeneic and H-2-matched allogeneic B cells and secreted IFN-gamma. Monoclonal Ab against CD4 and CD28 inhibited the proliferative response of ATL1 for syngeneic B cells. Interestingly, ATL1 did not respond to BXSB spleen or peritoneal macrophages, suggesting that B cells were able to either express accessory molecules necessary for T-cell triggering or present cryptic epitopes recognized by the autoreactive T cells. Moreover, ATL1 was able to help BXSB, but not C57BL/6, B cells producing IgG and IgM Abs against dsDNA and histone in vitro. Passive transfer of viable ATL1 cells into young female BXSB mice significantly accelerated the production of autoantibodies. Possible mechanisms of interaction between ATL1 and lupus B cells are further discussed.

Unique therapeutic effects of the Japanese-Chinese herbal medicine, Sairei-to, on Th1/Th2 cytokines balance of the autoimmunity of MRL/lpr mice

Sairei-to, one of the Japanese-Chinese herbal medicines has been used for the treatment of various diseases, especially collagen disease and edema in nephrotic syndrome. However, the mechanism of the therapeutic effects remains uncertain. Therefore, we investigated the immunological changes of skin, kidney, spleen cells and serum in autoimmune-prone MRL/lpr, MRL/n and C57BL/6J mice treated with Sairei-to. In MRL/lpr mice treated with Sairei-to, the improvement of proteinuria, reduction in the number of hematoxylin bodies in kidney, and reduced serum levels of blood urea nitrogen were observed. These results indicate that Sairei-to can improve or inhibit the progression of lupus nephritis. The proportion of CD19 and the serum levels of IgG1, which is one of the pathogenesis of lupus dermatoses and lupus nephritis, were significantly reduced in Sairei-to-treated MRL/lpr mice. Therefore, it is suspected that the B cell function was suppressed by Sairei-to. In addition, CD4/8 ratio in spleen cells and the degree of lymphoproliferation in MRL/lpr mice also decreased. Interestingly, IL-4 producing spleen cells were increased significantly by ELISPOT assay, and IFN-gamma mRNA expressions were reduced in Sairei-to-treated MRL/lpr mice. Regarding the Th balance, an imbalance towards Th1 predominance may play a significant role in MRL/lpr mice, and the Th1 axis was suppressed and the Th2 axis became predominant in Sairei-to-treated MRL/lpr mice. On the other hand, Th2 cell type immunoglobulins (IgG1) were suppressed. These results suggested that Sairei-to is potential for impairing shifted Th1/Th2 balance and hypergammaglobulinemia resulting in therapeutic effects.

Transgenic expression of a soluble complement inhibitor protects against renal disease and promotes survival in MRL/lpr mice

To investigate the role of complement in lupus nephritis, we used MRL/lpr mice and a transgene overexpressing a soluble complement regulator, soluble CR1-related gene/protein y (sCrry), both systemically and in kidney. Production of sCrry in sera led to significant complement inhibition in Crry-transgenic mice relative to littermate transgene negative controls. This complement inhibition with sCrry conferred a survival advantage to MRL/lpr mice. In a total of 154 animals, 42.5% transgene-negative animals had impaired renal function (blood urea nitrogen > 50 mg/dl) compared with 16.4% mice with the sCrry-producing transgene (p < 0.001). In those animals that died spontaneously, MRL/lpr mice with the sCrry-producing transgene did not die of renal failure, while those without the transgene did (blood urea nitrogen values of 46.6 +/- 9 and 122 +/- 29 mg/dl in transgene-positive and transgene-negative animals, respectively; p < 0.001). Albuminuria was reduced in those transgenic animals in which sCrry expression was maximally stimulated (urinary albumin/creatinine = 12.4 +/- 4.3 and 36.9 +/- 7.7 in transgene-positive and transgene-negative animals, respectively; p < 0.001). As expected in the setting of chronic complement inhibition, there was less C3 deposition in glomeruli of sCrry-producing transgenic mice compared with transgene-negative animals. In contrast, there was no effect on glomerular IgG deposition, levels of anti-dsDNA Ab and rheumatoid factor, or spleen weights between the two groups. Thus, long-term complement inhibition reduces renal disease in MRL/lpr mice, which translates into improved survival. MRL/lpr mice in which complement is inhibited still have spontaneous mortality, yet this is not from renal disease.

Selective accumulation of CCR4+ T lymphocytes into renal tissue of patients with lupus nephritis

OBJECTIVE

Some chemokine receptors, such as CCR5 and CCR4, are differentially expressed on Th1 and Th2 cells. To determine whether differential expression of the chemokine receptors occurs in patients with lupus nephritis, we examined the expression of CCR4 and CCR5 on peripheral blood lymphocytes and mononuclear cells infiltrated into the renal tissue of patients with lupus nephritis.

METHODS

The expression of CCR4 and CCR5 on CD4+,CD45RO+ cells was analyzed by flow cytometry and compared between patients with systemic lupus erythematosus (SLE) and healthy controls. Correlation between the absolute number of CCR4+ or CCR5+ cells and clinical parameters was also analyzed. Mononuclear infiltrates in the renal tissue of SLE patients were analyzed for the expression of CCR4, CCR5, and CD4 by immunohistochemical staining.

RESULTS

The absolute number of CCR4+, but not CCR5+, T lymphocytes in the peripheral blood was significantly decreased in the patients with SLE compared with that in the healthy controls, and this positively correlated with the serum levels of C3 and CH50. Most of the CD4+ T lymphocytes that infiltrated into the renal tissue of the patients with lupus nephritis expressed CCR4, but not CCR5.

CONCLUSION

These results suggest that CCR4+ T lymphocytes in peripheral blood, which represent Th2 cells, preferentially migrate into the renal tissue of patients with lupus nephritis. The maldistribution of CCR4+ T lymphocytes might be involved in the pathogenesis of lupus nephritis.

The expression and significance of intracellular T helper cytokines in systemic lupus erythematosus

To analyze the Th1 and Th2 paradigm of peripheral T helper cells in patients with systemic lupus erythematosus (SLE). The intracellular Th1 and Th2 cytokines were analyzed in fresh blood T cells from 20 SLE patients who had not yet received any treatment. Th1 and Th2 cells were quantitated based on their intracellular cytokine content as assessed by flow cytometry. Cytokine expressions were correlated with clinical features, laboratory findings, and disease activities. There was no difference in the expression of intracellular IFN-y, or IL-4 between SLE patients and healthy controls. However, the IL-2 and IL-10 levels were significantly higher and lower respectively in the lupus patients than in the control group. In addition, patients with arthritis had higher IFN-gamma expression than patients without arthritis. Moreover, patients with serositis or CNS involvement had higher IL-4 expression than in patients without these manifestations. There was no correlation between the SLEDAI scores and the cytokine expression levels. However, patients with serum anti-ds DNA antibodies had higher IL-10 levels than in those without these antibodies. The present study demonstrates that a Th1 pattern of intracellular cytokines predominates in patients with SLE prior to treatment. The pattern of particular intracellular T cell cytokines may suggest specific clinical manifestations and disease progression of SLE.

Immunomodulation by metals

Occupational or environmental exposure to metals is believed to affect human health adversely. One mechanism whereby metals can alter health is through modulation of immune homeostasis. Imbalances in immune regulation by metals can lead to inadequate or excessive production of inflammatory cytokines. Alternatively, metals can lead to inappropriate activation of lymphoid subsets involved in acquired immunity to specific antigens. Some resultant pathologies may include chronic inflammatory processes and autoimmune diseases. Metals may change the response repertoire by direct and indirect means by influencing expression of new antigens, new peptides, and/or antigen presentation by modifying the antigen-presenting complex. The differences in metal-induced immune responses between humans and the mechanisms of metal immunomodulation are discussed.

Binding of SLE autoantibodies to native poly(I), ROS-poly(I) and native DNA: a comparative study

Reactive oxygen species (ROS) are implicated in a variety of human diseases. The formation of pathogenic anti-DNA antibodies in systemic lupus erythematosus (SLE) has been extensively investigated. ROS-modified DNA has been found to be a better antigen for anti-DNA antibodies found in SLE sera. A comparative binding of SLE autoantibodies with native poly(I), ROS-poly(I) and nDNA has been studied. Affinity-purified SLE IgG exhibited a high degree of specificity towards the ROS-modified poly(I) in comparison to native DNA and native poly(I), reiterated visually by gel retardation assay. The data suggested that hydroxyl radical-modified nucleic acids like RNA and DNA might be agent for the induction of circulating SLE anti-DNA autoantibodies.

Outcome after transplantation of young patients with systemic lupus erythematosus: a report of the North American pediatric renal transplant cooperative study

BACKGROUND

The risk of progressing to end-stage renal disease in children with lupus glomerulonephritis is 18% to 50%. Published reports of transplantation secondary to end-stage renal failure in adult patients with systemic lupus erythematosus (SLE) demonstrate equivalent patient and graft survival. The purpose of this analysis is to compare patient and graft outcomes of pediatric SLE renal transplant recipients with an age-, race-, and gender-matched control group.

METHODS

A retrospective analysis of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database identified 100 renal transplants performed in 94 young SLE patients. A control group of 470 children having received 501 renal transplants was identified.

RESULTS

The SLE cohort was primarily female (82%), non-Caucasian (61%), adolescents and differed from the control group in being less likely to be preemptively transplanted, in receiving longer pretransplant dialysis, and in being likely to have received more than five pretransplant transfusions. After transplantation, there were no differences seen in patient survival at 3 years (89% vs. 95%, SLE vs. control) or in overall graft failure rates (31% vs. 29%, SLE vs. control). There was a trend toward poorer graft survival in non-white SLE patients receiving living donor grafts compared with white SLE patients. An increased graft failure rate was seen among those SLE cadaveric transplant recipients receiving peritoneal dialysis before transplant compared with controls and compared with SLE patients receiving hemodialysis. No differences were seen in rates of acute tubular necrosis or overall acute rejection incidence, although there was a significant increase in the percentage of living donor SLE patients who experienced greater than four rejection episodes. There were nonsignificant trends toward increased graft loss due to patient death with a functioning graft as well as increased mortality secondary to infection in the SLE patients.

CONCLUSIONS

The results of renal transplantation in young SLE patients are comparable to those seen in an age-, race- and gender-matched control group. The similar patient and graft survival is seen despite the SLE patients having an underlying disease with multiorgan involvement and despite receiving immunosuppression for potentially prolonged periods before transplantation. No outcome differences were seen except for an unexplained increase in the incidence of recurrent rejections (> or =4) in the living donor SLE patients as well as increased graft failure rate in those patients receiving cadaveric renal transplants after a period of peritoneal dialysis. The nonsignificant trends toward increased graft failures in non-white SLE patients receiving living donor grafts, increased graft loss secondary to death with a functioning graft, as well as the increased mortality due to infection deserve recognition and further study.