Faculty Bibliography

OBJECTIVE: To investigate which serologic and clinical findings predict adverse pregnancy outcome in patients with antiphospholipid antibody (aPL) and to test the hypothesis that a pattern of clinical and serologic variables can identify women at highest risk of adverse pregnancy outcome. METHODS: Women enrolled in a multicenter prospective observational study of risk factors for adverse pregnancy outcome in patients with aPL (lupus anticoagulant [LAC], anticardiolipin antibody [aCL], and/or antibody to beta(2) -glycoprotein I [anti-beta(2) GPI]) and/or systemic lupus erythematosus (SLE) were recruited for the present prospective study. Demographic, clinical, serologic, and treatment data were recorded at the time of the first study visit. The relationship between individual and combined variables and adverse pregnancy outcome was assessed by bivariate and multivariate analysis. RESULTS: Between 2003 and 2011 we enrolled 144 pregnant patients, of whom 28 had adverse pregnancy outcome. Thirty-nine percent of the patients with LAC had adverse pregnancy outcome, compared to 3% of those who did not have LAC (P < 0.0001). Among women with IgG aCL at a level of >/=40 units/ml, only 8% of those who were LAC negative had adverse pregnancy outcome, compared to 43% of those who were LAC positive (P = 0.002). IgM aCL, IgG anti-beta(2) GPI, and IgM anti-beta(2) GPI did not predict adverse pregnancy outcome. In bivariate analysis, adverse pregnancy outcome occurred in 52% of patients with and 13% of patients without prior thrombosis (P = 0.00005), and in 23% with SLE versus 17% without SLE (not significant); SLE was a predictor in multivariate analysis. Prior pregnancy loss did not predict adverse pregnancy outcome. Simultaneous positivity for aCL, anti-beta(2) GPI, and LAC did not predict adverse pregnancy outcome better than did positivity for LAC alone. CONCLUSION: LAC is the primary predictor of adverse pregnancy outcome after 12 weeks' gestation in aPL-associated pregnancies. Anticardiolipin antibody and anti-beta(2) GPI, if LAC is not also present, do not predict adverse pregnancy outcome.

OBJECTIVE.: The Systemic Lupus Collaborating Clinics (SLICC) revised and validated the American College of Rheumatology (ACR) SLE classification criteria in order to improve clinical relevance, meet stringent methodology requirements and incorporate new knowledge in SLE immunology. METHODS.: The classification criteria were derived from a set of 702 expert-rated patient scenarios. Recursive partitioning was used to derive an initial rule that was simplified and refined based on SLICC physician consensus. SLICC validated the classification criteria in a new validation sample of 690 SLE patients and controls. RESULTS.: Seventeen criteria were identified. The SLICC criteria for SLE classification requires: 1) Fulfillment of at least four criteria, with at least one clinical criterion AND one immunologic criterion OR 2) Lupus nephritis as the sole clinical criterion in the presence of ANA or anti-dsDNA antibodies. In the derivation set, the SLICC classification criteria resulted in fewer misclassifications than the current ACR classification criteria (49 versus 70, p=0.0082), had greater sensitivity (94% versus 86%, p<0.0001) and equal specificity (92% versus 93%, p=0.39). In the validation set, the SLICC Classification criteria resulted in fewer misclassifications (62 versus 74, p=0.24), had greater sensitivity (97% versus 83%, p<0.0001) but less specificity (84% versus 96%, p<0.0001). CONCLUSIONS.: The new SLICC classification criteria performed well on a large set of patient scenarios rated by experts. They require that at least one clinical criterion and one immunologic criterion be present for a classification of SLE. Biopsy confirmed nephritis compatible with lupus (in the presence of SLE autoantibodies) is sufficient for classification. (c) 2012 American College of Rheumatology.

OBJECTIVE: Membrane endothelial protein C receptor (mEPCR) is highly expressed in peritubular capillaries of kidneys from patients with active and poorly responsive lupus nephritis (LN). We investigated the hypothesis that changes in the microvasculature are widespread with extension to the dermal vasculature. METHODS: Skin biopsies from uninvolved skin (buttocks) were performed in 27 patients with LN and 5 healthy controls. Sections were stained with specific antibodies reactive with mEPCR, adiponectin, intercellular adhesion molecule-1 (ICAM-1), and CD31; then assessed by enumeration of stained blood vessels (percentage positive blood vessels) blinded to knowledge of clinical information. RESULTS: There was a significant increase in the prevalence of blood vessels that stained for mEPCR and ICAM-1 in patients compared to controls [94% vs 59% (p = 0.045) and 81% vs 67% (p = 0.037), respectively]. Adiponectin staining and CD31 staining were similar between the groups (45% vs 43% and 98% vs 92%). Dermal staining for mEPCR was greater in patients with proliferative glomerulonephritis than in those with membranous disease (96% vs 60%; p = 0.029). A composite of poor prognostic renal markers and death was significantly associated with greater expression of mEPCR staining. CONCLUSION: These data are consistent with the notion that in patients with LN, activation of the microvasculature extends beyond the clinically targeted organ. The insidious expression of this widespread vasculopathy may be a contributor to longterm comorbidities.

OBJECTIVES: Altered signalling in B cells is a predominant feature of systemic lupus erythematosus (SLE). The genes BANK1 and BLK were recently described as associated with SLE. BANK1 codes for a B-cell-specific cytoplasmic protein involved in B-cell receptor signalling and BLK codes for an Src tyrosine kinase with important roles in B-cell development. To characterise the role of BANK1 and BLK in SLE, a genetic interaction analysis was performed hypothesising that genetic interactions could reveal functional pathways relevant to disease pathogenesis. METHODS: The GPAT16 method was used to analyse the gene-gene interactions of BANK1 and BLK. Confocal microscopy was used to investigate co-localisation, and immunoprecipitation was used to verify the physical interaction of BANK1 and BLK. RESULTS: Epistatic interactions between BANK1 and BLK polymorphisms associated with SLE were observed in a discovery set of 279 patients and 515 controls from northern Europe. A meta-analysis with 4399 European individuals confirmed the genetic interactions between BANK1 and BLK. As BANK1 was identified as a binding partner of the Src tyrosine kinase LYN, the possibility that BANK1 and BLK could also show a protein-protein interaction was tested. The co-immunoprecipitation and co-localisation of BLK and BANK1 were demonstrated. In a Daudi cell line and primary naive B cells endogenous binding was enhanced upon B-cell receptor stimulation using anti-IgM antibodies. CONCLUSION: This study shows a genetic interaction between BANK1 and BLK, and demonstrates that these molecules interact physically. The results have important consequences for the understanding of SLE and other autoimmune diseases and identify a potential new signalling pathway

OBJECTIVES: Systemic lupus erythematosus (SLE) is a sexually dimorphic autoimmune disease which is more common in women, but affected men often experience a more severe disease. The genetic basis of sexual dimorphism in SLE is not clearly defined. A study was undertaken to examine sex-specific genetic effects among SLE susceptibility loci.METHODS: A total of 18 autosomal genetic susceptibility loci for SLE were genotyped in a large set of patients with SLE and controls of European descent, consisting of 5932 female and 1495 male samples. Sex-specific genetic association analyses were performed. The sex-gene interaction was further validated using parametric and non-parametric methods. Aggregate differences in sex-specific genetic risk were examined by calculating a cumulative genetic risk score for SLE in each individual and comparing the average genetic risk between male and female patients.RESULTS: A significantly higher cumulative genetic risk for SLE was observed in men than in women. (P=4.52x10-8) A significant sex-gene interaction was seen primarily in the human leucocyte antigen (HLA) region but also in IRF5, whereby men with SLE possess a significantly higher frequency of risk alleles than women. The genetic effect observed in KIAA1542 is specific to women with SLE and does not seem to have a role in men.CONCLUSIONS: The data indicate that men require a higher cumulative genetic load than women to develop SLE. These observations suggest that sex bias in autoimmunity could be influenced by autosomal genetic susceptibility loci

OBJECTIVE: High serum interferon alpha (IFNalpha) activity is a heritable risk factor for systemic lupus erythematosus (SLE). Auto-antibodies found in SLE form immune complexes which can stimulate IFNalpha production by activating endosomal Toll-like receptors and interferon regulatory factors (IRFs), including IRF5. Genetic variation in IRF5 is associated with SLE susceptibility; however, it is unclear how IRF5 functional genetic elements contribute to human disease.METHODS: 1034 patients with SLE and 989 controls of European ancestry, 555 patients with SLE and 679 controls of African-American ancestry, and 73 patients with SLE of South African ancestry were genotyped at IRF5 polymorphisms, which define major haplotypes. Serum IFNalpha activity was measured using a functional assay.RESULTS: In European ancestry subjects, anti-double-stranded DNA (dsDNA) and anti-Ro antibodies were each associated with different haplotypes characterised by a different combination of functional genetic elements (OR>2.56, p<1.9x10(-14) for both). These IRF5 haplotype-auto-antibody associations strongly predicted higher serum IFNalpha in patients with SLE and explained >70% of the genetic risk of SLE due to IRF5. In African-American patients with SLE a similar relationship between serology and IFNalpha was observed, although the previously described European ancestry-risk haplotype was present at admixture proportions in African-American subjects and absent in African patients with SLE.CONCLUSIONS: The authors define a novel risk haplotype of IRF5 that is associated with anti-dsDNA antibodies and show that risk of SLE due to IRF5 genotype is largely dependent upon particular auto-antibodies. This suggests that auto-antibodies are directly pathogenic in human SLE, resulting in increased IFNalpha in cooperation with particular combinations of IRF5 functional genetic elements.SLE is a systemic autoimmune disorder affecting multiple organ systems including the skin, musculoskeletal, renal and haematopoietic systems. Humoral autoimmunity is a hallmark of SLE, and patients frequently have circulating auto-antibodies directed against dsDNA, as well as RNA binding proteins (RBP). Anti-RBP autoantibodies include antibodies which recognize Ro, La, Smith (anti-Sm), and ribonucleoprotein (anti-nRNP), collectively referred to as anti-retinol-binding protein). Anti-retinol-binding protein and anti-dsDNA auto-antibodies are rare in the healthy population.1 These auto-antibodies can be present in sera for years preceding the onset of clinical SLE illness2 and are likely pathogenic in SLE.3 4

OBJECTIVE: Several confirmed genetic susceptibility loci for lupus have been described. To date, no clear evidence for genetic epistasis is established in lupus. We test for gene-gene interactions in a number of known lupus susceptibility loci. METHODS: Eighteen SNPs tagging independent and confirmed lupus susceptibility loci were genotyped in a set of 4,248 lupus patients and 3,818 normal healthy controls of European descent. Epistasis was tested using a 2-step approach utilizing both parametric and non-parametric methods. The false discovery rate (FDR) method was used to correct for multiple testing. RESULTS: We detected and confirmed gene-gene interactions between the HLA region and CTLA4, IRF5, and ITGAM, and between PDCD1 and IL21 in lupus patients. The most significant interaction detected by parametric analysis was between rs3131379 in the HLA region and rs231775 in CTLA4 (Interaction odds ratio=1.19, z-score= 3.95, P= 7.8x10(-5) (FDR</=0.05), P(MDR) = 5.9x10(-45) ). Importantly, our data suggest that in lupus patients the presence of the HLA lupus-risk alleles in rs1270942 and rs3131379 increases the odds of also carrying the lupus-risk allele in IRF5 (rs2070197) by 17% and 16%, respectively (P= 0.0028 and 0.0047). CONCLUSION: We provide evidence for gene-gene epistasis in systemic lupus erythematosus. These findings support a role for genetic interaction contributing to the complexity of lupus heritability