Complement fragment C3d is colocalized within the lipid rafts of T cells and promotes cytokine production.

UNLABELLED: The complement system plays an important role in tissue inflammation and damage in SLE patients. High levels of C3d were detected on the surface of erythrocytes and lymphocytes of SLE patients. The objective of this study was to assess the functional consequences of C3d fragments deposited on the surface membrane of SLE T cells. METHODS: 46 SLE patients, 43 patients with other autoimmune diseases (OAD) and 33 healthy individuals (N) were enrolled in this study. T cells were isolated from peripheral blood and flow cytometry studies were conducted to assess the levels of C3d fragments, Ca++ influx responses and cytokine production. Confocal microscopy was used to study co-localized molecules. Student's t-test was performed to determine statistical significance among study groups. RESULTS: A significant percentage of the SLE T cells were found to be positive for C3d (13.58 ± 3.92%) when compared with normal T cells (4.52 ± 2.92%) (p < 0.0000547) and T cells from patients with other autoimmune diseases (6.31 ± 4.57%) (p < 0.00513). Peak Ca++ influx responses were significantly higher in C3d- SLE T cells compared with C3d+ SLE T cells (p < 0.011). C3d+ T cells produced significantly more IL-2, IFN-gamma, IL-4 and IL-17. In contrast to the increased production of IL-2 by the C3d+ T cells, the overall SLE T cell population produced less IL-2 when compared with T cells from normal individuals or patients with other autoimmune disease. The C3d fragments were found to be localized within the lipid rafts. CONCLUSION: C3d fragments are localized in the lipid rafts of SLE T cells and contribute to abnormal T cell function by modulating Ca++ influx responses and increased cytokine production.

Prospective assessment of C4d deposits on circulating cells and renal tissues in lupus nephritis: a pilot study.

Complement activation plays a key role in the pathogenesis of lupus nephritis (LN), a severe complication of systemic lupus erythematosus (SLE). We prospectively evaluated 15 LN subjects and two control groups: 13 non-SLE renal subjects (control A) and 239 SLE subjects without LN (control B). All had C4d levels on circulating erythrocytes (E-C4d), reticulocytes (R-C4d) and platelets (P-C4d) measured by flow cytometry, while C4d deposition in renal tissue was semiquantitatively assessed in LN subjects and control A using immunoperoxidase staining. Compared with control A, LN biopsies had higher glomerular-C4d scores (p = 0.003), which were associated with more frequent granular glomerular immunofluorescence staining and electron dense deposits (p < 0.001). Compared with control A and B groups, LN subjects had higher E-C4d (p = 0.002 and p = 0.005) and R-C4d levels (p = 0.002 and p = 0.008), respectively. LN subjects were more likely to have P-C4d compared with control A (p = 0.016). In LN, only E-C4d correlated with National Institutes of Health (NIH) activity index (r = 0.55, p = 0.04). In conclusion, LN biopsies showed frequent glomerular-C4d staining associated with immune complex deposits. LN subjects had higher E-C4d and R-C4d levels compared with both control groups. E-C4d levels also correlated with NIH activity index. These findings suggest a potential role of C4d on circulating cells as a biomarker for lupus nephritis.

Acupuncture for systemic lupus erythematosus: a pilot RCT feasibility and safety study.

The objective of this study was to determine the feasibility of studying acupuncture in patients with systemic lupus erythematosus (SLE), and to pilot test the safety and explore benefits of a standardized acupuncture protocol designed to reduce pain and fatigue. Twenty-four patients with SLE were randomly assigned to receive 10 sessions of either acupuncture, minimal needling or usual care. Pain, fatigue and SLE disease activity were assessed at baseline and following the last sessions. Safety was assessed at each session. Fifty-two patients were screened to enroll 24 eligible and interested persons. Although transient side effects, such as brief needling pain and lightheadedness, were reported, no serious adverse events were associated with either the acupuncture or minimal needling procedures. Twenty-two participants completed the study, and the majority (85%) of acupuncture and minimal needling participants were able to complete their sessions within the specified time period of 5-6 weeks. 40% of patients who received acupuncture or minimal needling had >/=30% improvement on standard measures of pain, but no usual care patients showed improvement in pain. A ten-session course of acupuncture appears feasible and safe for patients with SLE. Benefits were similar for acupuncture and minimal needling.

Association of a common interferon regulatory factor 5 (IRF5) variant with increased risk of systemic lupus erythematosus (SLE).

Interferon regulatory factor 5 (IRF5) belongs to a family of transcription factors that control the transactivation of type I interferon system-related genes, as well as the expression of several other genes involved in immune response, cell signalling, cell cycle control and apoptosis. Two recent studies reported a significant association between the IRF5/rs2004640 T allele and systemic lupus erythematosus (SLE). The purpose of this study was to determine whether the reported rs2004640 T allele association could be replicated in our independent SLE case-control sample. We genotyped DNA samples from 370 white SLE-affected female subjects and 462 white healthy female controls using the TaqMan Assay-on-Demand for rs2004640, and performed a case-control genetic association analysis. Frequency of the rs2004640 T allele was significantly higher in cases than in controls (56.5% vs. 50%; P= 0.008). The odds ratio for T allele carriers was 1.68 (95% CI: 1.20 - 2.34; P= 0.003). Our results in an independent case-control sample confirm the robust association of the IRF5/rs2004640 T allele with SLE risk, and further support the relevance of the type I interferon system in the pathogenesis of SLE and autoimmunity.

Review of ACR hematologic criteria in systemic lupus erythematosus.

We have conducted a thorough literature review to evaluate the relative value of the hematologic criterion in making a diagnosis of systemic lupus erythematosus (SLE), its clinical relevance, and its prognostic significance. In the updated 1982 ACR criteria, the presence of one or more of the four elements: 1) hemolytic anemia (with reticulocytosis); 2) leukopenia (<4000/microL on two or more occasions); 3) lymphopenia (< 1500/microL on two or more occasions); or 4) thrombocytopenia (< 100,000/microL in the absence of offending drugs) is now considered as a single hematologic disorder. The sensitivity and specificity of the individual elements of the hematologic criterion range from 18 to 46% and 89 to 99%, respectively. The accuracy of the hematologic criterion requires proper interpretation. For example, many studies reported the presence of anemia that was not clearly defined and likely included anemia from etiologies other than hemolytic anemia, thereby causing an overestimation of the prevalence. In addition, medications such as corticosteroids and cytotoxic agents, and viral infections, can also contribute to a reduction in lymphocyte count. Despite these limitations, the SLICC committee recommends no change in the elements of the hematologic criterion when this criterion is properly interpreted and other causes of cytopenia are excluded.

Myocardial blood-flow response during mental stress in patients with coronary artery disease.

Positron emission tomography was used to quantify changes in myocardial blood flow during mental stress in patients with and without coronary artery disease. Blunted augmentation of myocardial blood flow during mental stress was observed in regions without significant epicardial stenosis.