Faculty Bibliography

OBJECTIVE: The Manhattan Lupus Surveillance Program (MLSP) is a population-based registry designed to determine the prevalence of systemic lupus erythematosus (SLE) in 2007 and the incidence from 2007 to 2009 among residents of New York County (Manhattan), New York, and to characterize cases by race/ethnicity, including Asians and Hispanics, for whom data are lacking. METHODS: We identified possible SLE cases from hospital records, rheumatologist records, and administrative databases. Cases were defined according to the American College of Rheumatology (ACR) classification criteria, the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria, or the treating rheumatologist's diagnosis. Rates among Manhattan residents were age-standardized, and capture-recapture analyses were conducted to assess case underascertainment. RESULTS: By the ACR definition, the age-standardized prevalence and incidence rates of SLE were 62.2 and 4.6 per 100,000 person-years, respectively. Rates were approximately 9 times higher in women than in men for prevalence (107.4 versus 12.5) and incidence (7.9 versus 1.0). Compared with non-Hispanic white women (64.3), prevalence was higher among non-Hispanic black (210.9), Hispanic (138.3), and non-Hispanic Asian (91.2) women. Incidence rates were higher among non-Hispanic black women (15.7) compared with non-Hispanic Asian (6.6), Hispanic (6.5), and non-Hispanic white (6.5) women. Capture-recapture adjustment increased the prevalence and incidence rates (75.9 and 6.0, respectively). Alternate SLE definitions without capture-recapture adjustment revealed higher age-standardized prevalence and incidence rates (73.8 and 6.2, respectively, by the SLICC definition and 72.6 and 5.0 by the rheumatologist definition) than the ACR definition, with similar patterns by sex and race/ethnicity. CONCLUSION: The MLSP confirms findings from other registries on disparities by sex and race/ethnicity, provides new estimates among Asians and Hispanics, and provides estimates using the SLICC criteria.

Background: A transmissible agent has long been suspected in the pathogenesis of SLE. We therefore investigated the potential contribution of the intestinal microbiome to LN.
Method(s): Blood and fecal samples from SLE patients were obtained, unless a patient had selective IgA deficiency, prior cytotoxic drugs, or antibiotics within four months. Fecal 16S rRNA NGS was performed. Sera samples were profiled for autoantibodies. Sera from two independent lupus cohorts were studied for validation.
Result(s): Compared to controls, the intestinal microbiome from SLE patients (N=61) showed decreased species richness diversity. The microbiomes of patients in clinical remission (based on SLEDAI) were most similar to healthy controls, while reductions in taxonomic complexity were most pronounced in those with high disease activity. Notably, SLE patients had an overall 5-fold greater representation of a particular species in the Blautia genus of the Lachnospiracaea family of obligate anaerobic Gram-positive cocci. Abundance of this species significantly correlated with serum IgG to a cell wall moiety from a strain of this species (P=0.002, N=61, Spearman) but not with 7 other strains. There was also a significant correlation between the distribution of SLEDAI scores and levels of these circulating anti-strain IgG antibodies (P=0.02, N=48). Using antigen treated with DNAse/proteinase K, levels of IgG anti-strain antibodies were significantly higher in those with active nephritis at time of sampling compared to SLE without renal activity (Cohort 1 P=0.01 N=48; Cohort 2 P=0.001, N=53, Mann-Whitney). Levels of anti-strain antibodies also significantly correlated with high-titer serum IgG to native DNA (P<0.0001, N=27), and inversely correlated with C3 and C4 (each P<0.01, N=61). High titers of these anti-bacterial antibodies were found in active Class III, IV and V LN.
Conclusion(s): These findings suggest a novel paradigm for the pathogenesis of LN: Specific strains of common intestinal commensal bacteria affect IgG-autoantibody responses in patients with LN. This is reminiscent of post-streptococcal GN, although the postulated intestinal bacterial bloom occurs without clinical infection

The signature lesion of SSA/Ro autoantibody-associated congenital heart block (CHB) is fibrosis and a macrophage infiltrate, supporting an experimental focus on cues influencing the fibroblast component. The transcriptomes of human fetal cardiac fibroblasts were analyzed using two complementary approaches. Cardiac injury conditions were simulated in vitro by incubating human fetal cardiac fibroblasts with supernatants from macrophages transfected with the SSA/Ro-associated hY3. The top ten upregulated transcripts in the stimulated fibroblasts reflected a type I interferon (IFN) response (e.g. IFI44L, MX1, MX2, and Rsad2). Within the fibrotic pathway, transcript levels of EDN1, PDE4D, CXCL2 and CXCL3 were upregulated, while others, including ADM, RAPGEF3, TIMP1, TIMP3 and DUSP1, were downregulated. Agnostic DAVID analysis revealed a significant increase in inflammatory genes, including C3AR1, the complement C3A receptor, F2RL3, and NCF2. In addition, the stimulated fibroblasts expressed high levels of phospho-MEF2C (a substrate of ERK5), which was inhibited by BIX 02189, a specific inhibitor of ERK5. Translation to human disease leveraged an unprecedented opportunity to interrogate the transcriptome of fibroblasts freshly isolated and cell sorted without stimulation from a fetal heart with CHB and a matched healthy heart. Consistent with the in vitro data, five IFN response genes were among the top ten most highly expressed transcripts in the CHB fibroblasts. In addition, the expression of matrix-related genes reflected fibrosis. These data support the novel finding that cardiac injury in CHB may occur secondary to abnormal remodeling due in part to upregulation of type 1 IFN response genes.