HLA-DR expression on lymphocyte subsets as a marker of disease activity in patients with systemic lupus erythematosus

A major problem in the management of SLE patients is to predict a flare or to distinguish between active and quiescent disease. Serological markers are widely used to assess disease activity, but many patients have close to or normal values for these parameters while exhibiting obvious disease-related signs and symptoms. This study aimed to determine which serological parameters, among ESR, ANA and anti-dsDNA antibody titres, CH50 and the HLA-DR expression on circulating T-lymphocyte subsets, best reflected the development of SLE flares. Sixty SLE patients were included, 34 with quiescent disease throughout the entire follow-up period and 26 who experienced an SLE flare defined as having active disease. According to univariate analysis, all parameters were significantly higher for patients with active disease, with the percentage of CD8+DR+ cells being the most significant parameter (P = 10-7). Multivariate logistic regression analysis identified three independent variables enabling the identification of a lupus flare: CH50, the CD8+DR+ and CD4+DR+ cell percentages among total lymphocytes. The CD8+DR+ cell percentage is the biological parameter most significantly associated with a flare (P < 0.001), even more powerful than CH50 (P < 0.01). HLA-DR expression on CD8+ lymphocytes clearly coincided with disease evolution in seven patients enrolled as having quiescent disease, but who experienced one flare during follow-up that subsequently resolved. The percentage of circulating CD8+DR+ lymphocytes appears to be a biological marker which accurately reflects disease activity. A larger prospective study is needed to demonstrate the real efficacy of this marker in predicting an exacerbation in SLE patients.     

C3b receptor (CR1) expression on the polymorphonuclear leukocytes from patients with systemic lupus erythematosus.

Polymorphonuclear leukocytes (PMN) C3b receptor (CR1) numbers have been measured in 14 normal individuals and 15 patients with SLE. The results in the normals showed that PMN possess three distinct pools of CR1. CR1 expression was lowest at 0 degrees C (mean 86,000 +/- s.e.m. 7,000), but increased when the cells were incubated at 37 degrees C (125,000 +/- 16,000) or when the cells were exposed to the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP, 10(-5) mol 1) at 37 degrees C (207,000 +/- 21,000). The increased expression at 37 degrees C was not dependent upon protein synthesis, an intact cytoskeleton or energy. Although the response to FMLP did not require de novo protein synthesis, increased CR1 expression was dependent upon an intact cytoskeleton and energy. All three PMN CR1 pools were reduced in patients with active SLE, but were normal in those in whom the disease was inactive. Serial studies performed on three SLE patients showed that PMN CR1 numbers were low during periods of disease activity and increased during remission. These data suggest that low PMN CR1 numbers in SLE are a consequence of the disease.     

The antichromatin antibodies can be useful as a diagnostic tool and disease activity marker of systemic lupus erythematosus in Koreans

We have investigated the clinical utility of antichromatin antibodies for the diagnosis of SLE and as a marker of disease activity in Korean SLE patients. Blood samples were collected from SLE patients, lupus syndrome patients having only two or three of ACR classification criteria for SLE and normal controls. The level of antichromatin antibody was measured by enzyme linked immunosorbent assay and expressed as arbitrary unit. The antichromatin antibody levels of the SLE and lupus syndrome patients were higher than NC. The antichromatin antibody levels were significant higher in SLE patients with arthritis. A significant correlation was found between the level of antichromatin antibodies and each of anti-dsDNA antibody, leukopenia, complement and SLEDAI. The change of antichromatin antibody levels showed a positive correlation with the change of SLEDAI in serial samples. These data suggest that the antichromatin antibodies appear to be a useful laboratory test that can help in the diagnosis and assessment of SLE.     

CR1 on erythrocytes of Brazilian systemic lupus erythematosus patients: the influence of disease activity on expression and ability of this receptor to bind immune complexes opsonized with complement from normal human serum

Hypocomplementaemia and low expression of CR1 on erythrocytes (E) of patients with systemic lupus erythematosus (SLE) are associated with defective clearance of circulating immune complexes (IC) and so they may have pathogenic significance. Here, we investigated whether the reduced CR1/E in SLE patients per se might affect the binding of IC to CR1/E. First, we analysed the expression of CR1 on E of active (n=30) and inactive (n=34) SLE patients using a FITC-conjugated mouse anti-CR1 monoclonal antibody E11 and flow cytometry. Both groups of patients had a significantly reduced CR1/E expression compared with healthy controls (n=40). It was also observed that the number of E bearing CR1 was reduced in both groups of SLE patients studied. Second, we determined the functional activity of CR1/E by measuring the binding to E of FITC-bovine serum albumin (BSA)/rabbit anti-BSA complexes, formed at equivalence, which were opsonized with complement from normal human serum (NHS). On the other hand, we did not find differences between the patient and control groups in the ability of E to bind IC/NHS. There was also a positive correlation between the CR1/E expression and the number of E bearing CR1 in control and inactive SLE groups, which was not observed in the group of active SLE patients. Considering the involvement of low levels of complement and CR1/E expression on complex processing, in this in vitro model the results show that an effective coating of the complexes with complement is sufficient to bind them preferentially to CR1 over normal levels of receptor expression.     

Human complement receptor 2 (CR2/CD21) as a receptor for DNA: Implications for its roles in the immune response and the pathogenesis of systemic lupus erythematosus (SLE)

Human CR2 is a B cell membrane glycoprotein that plays a central role in autoimmunity. Systemic lupus erythematosus (SLE) patients show reduced CR2 levels, and complete deficiency of CR2 and CR1 promotes the development of anti-DNA antibodies in mouse models of SLE. Here we show that multiple forms of DNA, including bacterial, viral and mammalian DNA, bind to human CR2 with moderately high affinity. Surface plasmon resonance studies showed that methylated DNA bound with high affinity with CR2 at a maximal K(D) of 6nM. DNA was bound to the first two domains of CR2 and this binding was blocked by using a specific inhibitory anti-CR2 mAb. DNA immunization in Cr2(-/-) mice revealed a specific defect in immune responses to bacterial DNA. CR2 can act as a receptor for DNA in the absence of complement C3 fixation to this ligand. These results suggest that CR2 plays a role in the recognition of foreign DNA during host-immune responses. This recognition function of CR2 may be a mechanism that influences the development of autoimmunity to DNA in SLE.     

T lymphocyte expression of complement receptor 2 (CR2/CD21): a role in adhesive cell-cell interactions and dysregulation in a patient with systemic lupus erythematosus (SLE).

Complement receptor 2 (CR2, CD21), the receptor for both the C3d,g portion of human complement component C3 and the Epstein-Barr virus, has been recently described on peripheral T cells. By using dual stain flow cytometric analysis, we have also observed that a peripheral T lymphocyte subpopulation of normal healthy donors bears CR2 in a range varying from 1.1 to 23.2% (mean 12.6%) of total CD3+ cells. T lymphocytes from nine patients with inactive SLE expressed CR2 in a similar range. Three patients with active SLE were also studied. One of them, having neuropathy and glomerulonephritis, displayed an expansion of the CR2 T cell subpopulation which reached as much as 89% of total CD3+ cells. To examine potential functional roles of T cell CR2, cells from a Jurkat-derived CR2 expressing T cell line were found to bind in vitro to human CR2-, complement-coated K562 cell targets in a CR2- and complement-dependent fashion. Based on these studies, we hypothesize that CR2 might act to increase adherence of T cells to nucleated target cells bearing C3d,g, a function which may be relevant to cytotoxicity or other T cell activities requiring cell-cell interaction.     

Circulating intercellular adhesion molecule 1 as a new activity marker in patients with systemic lupus erythematosus

Summary To determine the value of soluble intercellular adhesion molecule 1 (sICAM-1) as a measure of disease activity in patients with systemic lupus erythematosus (SLE), 25 patients with SLE were studied in an active and in a less active state. Disease activity was assessed according to the New York Hospital for Special Surgery System (NYHSS) score. The levels of sICAM-1 were significantly higher in an active than in a less active state of the disease (P<0.001). The correlation between ICAM and the NYHSS score was r=0.3412 (P<0.001) and that between NYHSS index and soluble interleukin-2 receptors (sIL-2R) was r=0.6620 (P<0.001). There was a good correlation between levels of sICAM-1 and sIL-2R (r=0.6792, P<0.001). Both sICAM-1 and sIL-2R were positively and significantly correlated with an increase in the erythrocyte sedimentation rate, but only sIL-2R levels were significantly correlated with increased dsDNA antibodies and with a decrease in serum complement factor C₃. Our data suggest that sICAM-1 reflects disease activity in patients with SLE, but this parameter per se should not be used to guide the therapeutic decision in SLE patients suspected of suffering from exacerbation of disease.Abbreviations ARA American Rheumatism Association - ELISA Enzyme-linked immunosorbent assay - IFN- interferon- - IL interleukin - LFA-1 leukocyte function associated antigen 1 - NYHSS New York Hospital for Special Surgery System - sICAM-1 soluble intercellular adhesion molecule-1 - sIL-2R soluble interleukin-2 receptor - SLE systemic lupus erythematosus - TNF- tumor necrosis factor-     

Evaluation of mortality,disease activity,treatment, clinical and immunological features of adult and late onset systemic Lupus erythematosus

Abstract

Objectives: We retrospectively compared disease activity, treatment, clinical and laboratory features, and rate of mortality of 535 SLE patients with adult and late disease onset.

Methods: patients were divided into two groups based on the onset of the disease before or after 50 years of age. Clinical data were collected from medical reports. Disease activity was measured by ECLAM score. Parameters were compared by χ²-test, Fisher’s test, Student’s t or the Mann–Whitney test.

Results: Forty patients (7.5%) were included in the late SLE onset group (group A), while 495 (92.5%) in the adult SLE onset group (group B). Sicca symptoms were more frequent in group A (p?<?0.0008), while glomerulonephritis (p?<?0.0069), reduced C3 (p?<?0.0006) and low C3 (p?<?0.00002) and C4 levels (p?<?0.0006) were more prevalent in group B. Twenty-two deaths (4.3%) were recorded: 14 (2.8%) in group B and 8 (20%) in group A. Deaths were mainly due to infections in group B (28.5%) and cardiovascular events in group A (50%). A lower use of HCQ and LDA were recorded in deceased versus living patients (p?<?0.0001 and 0.0166, respectively), while a higher ECLAM score was measured at onset in dead versus living patients (p?<?0.048).

Conclusions: Late onset SLE occurred in 7.5% of patients and it was associated with sicca symptoms. The use of HCQ and LDA is positively correlated with survival. Death in late onset SLE occurred more frequently for cardiovascular involvement. Higher disease activity at onset of the disease might represent a poor prognostic factor for death in adult onset.     

C4a anaphylatoxin levels as an indicator of disease activity in systemic lupus erythematosus

The use of a synthetic protease inhibitor, nafamstat mesilate, has enabled reliable estimations of in vivo complement activation to be made in systemic lupus erythematosus (SLE). Elevation of C3a anaphylatoxins was found in two out of 24 patients and elevation of C4a anaphylatoxins was found in 20 out of 24 patients, confirming that complement activation, predominantly by the classical pathway, is a common occurrence in the disease. Significantly higher levels of C4a anaphylatoxin were found in 16 patients, with more aggressive disease requiring supplementary treatment with azathioprine, while the remaining eight patients, with less severe disease, required purely steroid therapy. Very strong associations between elevated C4a anaphylatoxins and raised DNA antibody titres, C1q binding activity and low complement C4 levels were also observed, suggesting that anaphylatoxin measurement may be a sensitive additional method for monitoring disease activity in SLE.     

红细胞补体受体1水平在系统性红斑狼疮发病作用的研究

目的:研究红细胞补体受体1(Erythrocyte receptor type 1,E-CR1)水平与系统性红斑狼疮(Systemic lupus erythe-matosus,SLE)疾病活动性及免疫异常之间的相关性,探讨E-CRI在SLE发病中的作用.方法:使用流式细胞仪检测技术测量了72例SLE患者和20例正常对照者末梢血中E-CR1水平,同时测定SLE患者血清补体(C3、C4)、免疫球蛋白(IgG、IgA、IgM)、Υ-球蛋白(Υ-G)及血沉,测定SLE患者血细胞计数,包括:白细胞(WBC)、红细胞(RBC)、血红蛋白(HGB)、红细胞比容(HCT)、平均红细胞容积(MCV)及血小板(PLT).对72例SLE患者做狼疮活动性测量(slAM)评分.结果:SLE患者E-CR1水平明显低于对照组(20.25±9.15/57.00±10.41,P＜0.01).在SLE患者中,E-CR1水平与IgG、Υ-G及血沉呈明显的负相关(P＜0.05);与HGB有非常明显的正相关(P＜0.01),与HCT有明显正相关性(P＜0.05);与SLAM呈显著线性负相关(P＜0.01).活动期SLE患者(n=46)E-CR1水平明显低于非活动期SLE患者(n=26)E-CR1水平(P＜0.05).在活动期SLE患者中,E-CR1水平与RBC、HGB、HCT均有非常明显正相关性(P＜0.01);与血沉和SLAM有负的线性相关(P＜0.011).结论:E-CR1水平降低可能是SLE发病的起始环节之一;免疫球蛋白(IsG及Υ-G)水平升高及RBC、HGB、HCT降低可能与E-CR1水平进一步降低有关,从而使SLE病情加重;E-CR1可作为SLE疾病活动性指标之一.     

Influence of minor thermal injury on expression of complement receptor CR3 on human neutrophils.

Thermal injury is well known to inhibit functions of the circulating neutrophil related to its role in host defense against infection, but the mechanism(s) of this phenomenon are not fully understood. To gain further clues to these mechanisms, the authors have studied patients with thermal injury in terms of altered expression of neutrophil cell membrane receptors for the opsonic complement-derived ligand C3bi--complement receptor Type 3, or CR3. CR3 expression was selected for study because an increase in the number of receptors on the cell surface can be stimulated by products of complement activation known to accumulate after thermal injury and because of the role of CR3 in phagocytic and adherence functions of the neutrophil. Expression of CR3 was monitored semiquantitatively by flow cytometry with the use of a murine monoclonal antibody (OKM1) specific for an antigen (CD11) associated with this receptor. Patients evaluated were limited in this study to those with minor degrees of thermal injury (second-degree burn involving less than 20% of total body surface area) so that possible confounding effects of major injury and its complications could be eliminated. It was observed that patient neutrophil CR3 becomes significantly up-regulated during the first week, as early as 1 day after injury. The maximum level of expression of CR3 averaged greater than 150% (range, 70-314%) of the respective minimum level observed for each patient. The minimum levels of expression of CR3 on patient neutrophils, reached 11-37 days after injury for 7 of 8 patients, were comparable to the level of expression of CR3 on unstimulated control neutrophils. Such temporal up-regulation of patient neutrophil CR3 suggests the early generation of stimuli of CR3 mobilization in response to thermal injury. Increased numbers of CR3 on patient neutrophils may augment microbicidal function and enhance or inhibit delivery of cells to the burn site.     

Effect of plasmapheresis on ligand binding capacity and expression of erythrocyte complement receptor type 1 (CR1) of patients with systemic lupus erythematosus (SLE)

The functional activity and the expression of CR1 on the erythrocytes (E) of patients with SLE were, respectively, determined by measuring the binding to E of either complement-opsonized bovine serum albumin (BSA)-anti-BSA immune complexes (ICC) or specific anti-ECR1 MoAbs. We found that both the functional activity and levels of ECR1 in SLE patients homozygous for ECR1 high density allele were significantly lowered compared with healthy controls having the same allele. Soon after plasmapheresis there was a significant increase in E ICC binding activity, and this increased functional activity was stable. Moreover, plasmapheresis reduced the level of immune complexes demonstrable in the circulation of the patients. The expression of ECR1 determined with several different anti-CR1 MoAbs was also elevated as a consequence of plasmapheresis. This elevation was observed for both MoAb 1B4, which competes for the ICC binding site of ECR1, and for MoAb HB8592, which does not, but the time course for the increase in binding of the two MoAbs was different, in that the epitope recognized by MoAb 1B4 increased more rapidly. The present results, considered in the context of previous findings, suggest that more than one mechanism may be operative with respect to the effects of the plasmapheresis in increasing ECR1 levels defined by different epitopes on the molecule.     

Protooncogene expression in peripheral blood mononuclear cells from patients with systemic lupus erythematosus as an indicator of the disease activity

In the present study, we examined the various protooncogene expressions in PBMC (peripheral blood mononuclear cell) of systemic lupus erythematosus (SLE) patients to determine if they could be an indicator for the disease activity. We divided SLE patients into "very active," "active," and "remitting" states according to the clinical symptoms in addition to the laboratory data peculiar to SLE. In addition, we determined the amount of circulating immune complex (IC) as one of the representative laboratory indicators for the disease activity. We found a positive correlation with either c-myc or c-myb expression and the amounts of IC and clinical disease activity. The degree of c-myc and c-myb expression was significantly reduced along with or prior to the amelioration of clinical symptoms and improvement as determined by laboratory data under treatment with prednisolone and/or azathioprine administration. The degree of c-myc and c-myb gene expression had no direct relation to the presence of particular clinical sign(s) or autoantibody. The expression of the c-raf gene was found in SLE and other systemic autoallergic patients although it showed no correlation with the disease activity. No significant expression of c-src, c-ras, c-fos, c-fgr, c-fps, c-fes, c-fms, c-yes, c-rel, c-abl, c-mos, c-sis, and c-erb B genes was found in the patients. c-myc and c-myb expression as having pathogenic and clinical significance is discussed.     

A new mouse anti-mouse complement receptor type 2 and 1 (CR2/CR1) monoclonal antibody as a tool to study receptor involvement in chronic models of immune responses and disease

Although reagents are available to block mouse complement receptor type 2 and/or type 1 (CR2/CR1, CD21/CD35) function in acute or short term models of human disease, a mouse anti-rat antibody response limits their use in chronic models. We have addressed this problem by generating in Cr2−/− mice a mouse monoclonal antibody (mAb 4B2) to mouse CR2/CR1. The binding of murine mAb 4B2 to CR2/CR1 directly blocked C3dg (C3d) ligand binding. In vivo injection of mAb 4B2 induced substantial down regulation of CR2 and CR1 from the B cell surface, an effect that lasted six weeks after a single injection of 2 mg of mAb. The 4B2 mAb was studied in vivo for the capability to affect immunological responses to model antigens. Pre-injection of mAb 4B2 before immunization of C57BL/6 mice reduced the IgG1 antibody response to the T-dependent antigen sheep red blood cells (SRBC) to a level comparable to that found in Cr2−/− mice. We also used the collagen-induced arthritis (CIA) model, a CR2/CR1-dependent autoimmune disease model, and found that mice pre-injected with mAb 4B2 demonstrated substantially reduced levels of pathogenic IgG2a antibodies to both the bovine type II collagen (CII) used to induce arthritis and to endogenous mouse CII. Consistent with this result, mice pre-injected with mAb 4B2 demonstrated only very mild arthritis. This reduction in disease, together with published data in CII-immunized Cr2−/− mice, confirm both that the arthritis development depends on CR2/CR1 receptors and that mAb 4B2 can be used to induce biologically relevant receptor blockade. Thus mAb 4B2 is an excellent candidate for use in chronic murine models to determine how receptor blockage at different points modifies disease activity and autoantibody responses.     

Structural polymorphisms of complement receptor 1 (CR1) in systemic lupus erythematosus (SLE) patients and normal controls of three ethnic groups

CR1 exhibits a molecular weight polymorphism and variability in the number of C3b-binding sites. Because this may affect immune complex clearance, we used erythrocytes to investigate the CR1 size polymorphism in SLE patients from three ethnic groups. The CR1-C allele was found more frequently in African–Americans, but the frequency did not differ between controls (10%, n = 63) and SLE patients (9%, n = 79). A 160-kD band similar to CR1-C was noted in a number of patients and was shown to be a proteolytic cleavage fragment. The study shows that the smallest form of CR1, i.e. CR1-C, is not a genetic risk factor for SLE and that the frequencies of the CR1 structural alleles do not differ from race-matched healthy controls.     

Phagocytic efficacy of macrophage-like cells as a function of cell cycle and Fcgamma receptors (FcgammaR) and complement receptor (CR)3 expression

Previous studies have shown that the efficiency of phagocytosis is a function of cell cycle and that phagocytosis promotes cell cycle progression. Because phagocytosis is dependent on cellular receptors we hypothesized that Fcgamma receptors (FcgammaR) and complement receptors (CR) expression varied with cell cycle. Consequently, we used centrifugal elutriation of macrophage-like cells, fluorescence activated cell sorting analysis and receptor staining to investigate expression of FcgammaR and CR as a function of cell cycle. We confirmed that FcgammaR expression on macrophage-like cells increased as the cells progressed from G1 to G2 phases. Moreover, CR3 expression varied as a function of cell cycle in a manner similar to FcgammaR. Correlation of receptor expression with cell size showed that FcgammaR and CR3 expression on macrophages was determined largely by cell size enlargement during the cell cycle. The efficacy of both Fc- and complement-mediated phagocytosis of live Cryptococcus neoformans (Cn) showed a biphasic pattern with the efficacy of phagocytosis decreasing when the cells approached the G1-S interface, which paralleled the changes in receptor surface expression when cells exited G1 phase. Live Cn cells were significantly more resistant to phagocytosis than dead cells at all stages of macrophage-like cell cycle. In contrast to live cells, the efficacy of phagocytosis of dead Cn decreased as surface receptor expression increased. Hence, the efficacy of phagocytosis in this system as function of cell cycle is not related to phagocytic receptor expression.