Faculty Bibliography

We recently identified a novel non-synonymous variant, rs1143679, at exon 3 of the ITGAM gene associated with systemic lupus erythematosus (SLE) susceptibility in European-Americans (EAs) and African-Americans. Using genome-wide association approach, three other studies also independently reported an association between SLE susceptibility and ITGAM or ITGAM-ITGAX region. The primary objectives of this study are to assess whether single or multiple causal variants from the same gene or any nearby gene(s) are involved in SLE susceptibility and to confirm a robust ITGAM association across nine independent data sets (n = 8211). First, we confirmed our previously reported association of rs1143679 (risk allele 'A') with SLE in EAs (P = 1.0 x 10(-8)) and Hispanic-Americans (P = 2.9 x 10(-5)). Secondly, using a comprehensive imputation-based association test, we found that ITGAM is one of the major non-human leukocyte antigen susceptibility genes for SLE, and the strongest association for EA is the same coding variant rs1143679 (log(10)Bayes factor=20, P = 6.17 x 10(-24)). Thirdly, we determined the robustness of rs1143679 association with SLE across three additional case-control samples, including UK (P = 6.2 x 10(-8)), Colombian (P = 3.6 x 10(-7)), Mexican (P = 0.002), as well as two independent sets of trios from UK (P(TDT) = 1.4 x 10(-5)) and Mexico (P(TDT) = 0.015). A meta-analysis combing all independent data sets greatly reinforces the association (P(meta) = 7.1 x 10(-50), odds ratio = 1.83, 95% confidence interval = 1.69-1.98, n = 10 046). However, this ITGAM association was not observed in the Korean or Japanese samples, in which rs1143679 is monomorphic for the non-risk allele (G). Taken together along with our earlier findings, these results demonstrate that the coding variant, rs1143679, best explains the ITGAM-SLE association, especially in European- and African-derived populations, but not in Asian populations

Premature atherosclerotic cardiovascular disease (ASCVD) is a common and devastating complication of systemic lupus erythematosus (SLE). It is likely that immunologic derangements contribute to premature ASCVD in these patients, possibly by disrupting homeostatic mechanisms that orchestrate cholesterol balance in monocytes/macrophages in the artery wall. CD36, a macrophage scavenger receptor responsible for recognition and internalization of oxidized lipids, is a major participant in atherosclerotic foam cell formation. We hypothesized that lupus plasma would affect CD36 expression in a pro-atherogenic manner in THP-1 human monocytes and differentiated macrophages. SLE patient plasma markedly stimulated expression of CD36 message in a dose-dependent fashion in THP-1 human monocytes. A 50% volume/volume concentration of plasma derived from SLE patients increased CD36 mRNA by 71 +/- 8% (n = 3, P < 0.001) above 50% normal human plasma. 50% SLE patient plasma increased CD36 mRNA expression to 290 +/- 12% of no-plasma control (n = 3, P < 0.001), compared with only 118 +/- 3.7% of control in the presence of 50% normal human plasma (n = 3, not significant). 50% lupus plasma also upregulated CD36 protein expression by 482.3 +/- 76.2% (n = 4, P < 0.05), whereas the presence of 50% normal human plasma increased the CD36 protein level by only 239.8 +/- 61.9% (n = 4, P < 0.05). To our knowledge, this is the first demonstration that CD36 expression is enhanced by plasma from patients with an autoimmune disorder. Premature atherosclerosis is common in SLE patients. Upregulation of CD36 may contribute to this pathological process by increasing vulnerability to cholesterol overload. Demonstration of disrupted cholesterol homeostasis in this select group of patients provides further evidence of the involvement of the immune system in atherogenesis and may inform us of the role of CD36 in the general atherogenic process. CD36 may provide a novel therapeutic target in the treatment of ASCVD in SLE patients

Purpose: SLE patients (pts) with moderate to severe disease activity (>= 1 BILAG A or >= 2 BILAG B domain scores) despite background immunosuppressives and corticosteroids, were randomized to placebo (PLA) or rituximab (RTX). Although differences in primary and secondary outcome measures were not observed, an exploratory analysis was performed to evaluate the impact of RTX on the intensity and frequency of disease flares. Our objectives were to assess in those pts who achieved response whether RTX affected: 1) time to moderate or severe flares, 2) annualized flare rates, and 3) prednisone usage during flares. Methods: The BILAG index was scored every 4 wks for 52 wks after the first study drug treatment. Only pts who achieved response (BILAG C, D, or E scores for all domains before wk 52) were included in this analysis. A severe flare was defined as >= 1 BILAG A or > 3 BILAG B domain scores in a pt who previously achieved response; an A flare was defined as >= 1 new BILAG A domain scores; a moderate flare was defined as 2 BILAG B domain scores following response. Kaplan-Meier estimates were used to assess time to flare. Annualized flare rates were calculated using the number of flares a patient experienced during the study; the p-value was based on Poisson regression model. Only flares that occurred after the protocol-mandated prednisone taper at 12 wks were incorporated into the analysis of prednisone usage during flares. Results: A response was achieved in 58 (66.0%) of 88 PLA-treated and 127 (75.1%) of 169 RTX-treated pts during the study, and these patients qualified for subset analysis. Whereas the times to first moderate or severe flare were not different in the two treatment groups, there was a trend towards a prolonged time to first A flare in the RTX group (HR=0.612; p=0.052). Annualized severe and moderate flare rates were similar in both groups, but the mean annualized A flare rate in the RTX group was significantly lower than in the PLA group (0.86 vs 1.41; p=0.038). Prednisone was increased in 20 of 101 (20.7%) of the A flares and was not significantly different between the RTX and PLA groups (24% vs 14%; p=0.204). Pts with the highest initial prednisone dosing (> 60 mg/day) had lower treatment rates (14.0%). In one month, 44/81 (54.3%) of the untreated A flare improved to B or better. Conclusion: There was no difference between PLA and RTX in preventing moderate or severe flares after a response was achieved. However, RTX treatment was associated with a lower annualized A flare rate, and a trend towards prolonging the time to A flare. Prednisone rescue following A flares was low compared to observational cohorts, possibly reflecting a reluctance to reinitiate prednisone, or reduced BILAG A severity, in this trial

Purpose: The original SELENA Flare Index (SFI) performed well in the SELENA trials to separate severe from mild/moderate flares. However, in current clinical trials it is important to also separate mild from moderate flares. Method: As part of the Lupus Foundation of America's International Flare Definition and Validation initiative, the SELENA Flare Index (SFI) was revised through a series of consensus conference calls. There was an initial review and discussion of the strengths and weaknesses of the SFI in SELENA and industry trials. Each call reviewed organ specific definitions of mild, moderate and severe flare. Definitions were discussed and re-reviewed until consensus was reached. Results:The revised SFI is organ-system based, and is not linked to the SLEDAI. For each organ system, suggested clinical manifestations are given for each category, but the intended treatment decision (if it is higher) overrides the clinical description in each category. Specifically, a mild flare is assigned if there is either no treatment, or initiation of hydroxychloroquine, prednisone <= 7.5 mg/day or a non-immunosuppressive therapy. Definition of a Moderate flare is consistent with use of prednisone > 7.5 mg/day but less than 0.5 mg/kg/day, or immunosuppressive therapy (other than cyclophosphamide), and Severe flare prednisone (or equivalent) >= 0.5 mg/kg/day, cyclophosphamide, biologic treatment, or hospitalization. Three mild flares are considered a moderate flare. Conclusion: The new SFI is organ system-based. The choice of recommended treatment overrides the clinical definition when the treatment choice is higher

Purpose: Patients (pts) with SLE develop widespread vascular inflammation and life threatening thrombotic events which are not completely explained by typical antiphospholipid antibodies. Since EPCR is a critical regulator at a crossroads of inflammation and thrombosis, two SNPs were evaluated in 199 active SLE pts to determine if genotype has an impact on circulating sEPCR, autoantibodies to EPCR, and thrombotic risk. Methods: Genotyping was performed by RTPCR with TaqMan primers for rs6936 A-G (serine to glycine) and rs7014 G-C (3' UTR). Circulating sEPCR was quantified by the ASSERACHROM sEPCR ELISA (Stago). Antibodies to EPCR were measured by a novel ELISA, calibrated against sera from 60 healthy individuals. Medical history and disease activity scores were obtained at the time of sampling. Results: Mean pt age was 39.1, 89.9% female, 62.3% Caucasian, 25.6% African descent and 12.1% Asian. There was no demographic bias in rs6936 genotypes, but most African descent pts were homozygous for G at rs7014 (40/51 vs 46/148 in others, p <0.001). Lupus activity (by BILAG) was the same between groups with overall mean (SD) score of 6.9 (4.3), suggesting moderate vascular inflammation throughout the population. In pts with the genotype rs6936 AA, median sEPCR was 145 ng/ml vs 317 ng/ml in non-AA (p <0.001). There was also a difference between genotypes at rs7014: 130 ng/ml in CC pts vs 164 in non-CC (p=0.005). Median sEPCR of 37 pts who carried both of the low sEPCR genotypes was 130 ng/ml vs 317 ng/ml in the rest of the population (p<0.001). Low C4 complement was unevenly distributed in rs7014 genotypes, found in 25% of GG, 41.6% of GC and 33.3% of CC, (p=0.041, GG vs GC). More women with rs6936 AA had a history of pregnancy loss and/or pre-eclampsia (23.6% vs 8% of those with G alleles in that gene, p=0.054) and the same for rs7014 (37.8% CC vs 17% with G alleles, p=0.011). Overall pts with a history of pregnancy complications, arterial and/or venous thromboses were also increased in rs6396 AA, 32.9% vs 15% in non-AA (p=0.06) and rs7014 CC, 37.8% vs 26.7% in non-CC (p=ns). Combining genotypes in assessing thrombotic risk, AA/CC women had a high rate of pregnancy complications (14/35 or 40% vs 3/35 or 8.57% of non-AA/non-CC (p=0.004). Pts with any type of thrombotic event included 14/37 (37.8%) of AA/CC vs 6/38 (15.7%) of non-AA or CC (p=0.039). 38 pts had autoantibodies to EPCR, more common in rs6936 AA than in pts with the G allele (32/162 vs 6/38 (p=ns) and more common in rs7014 pts with G allele than CC (34/163 vs 4/37) (p=ns). There were no pts with both 6936 AA and a G allele in 7014 even though each genotype represents about 19% of the population. Conclusion: These data suggest that genetic variants influence sEPCR levels in active lupus and may increase complement consumption, autoantibody formation and thrombotic complications in these patients