The genetic diversity of multiple sclerosis risk among Hispanic and African American populations living in the United States

BACKGROUND

Substantial progress has been made toward unraveling the genetic architecture of multiple sclerosis (MS) within populations of European ancestry, but few genetic studies have focused on Hispanic and African American populations within the United States.

OBJECTIVE

We sought to test the relevance of common European MS risk variants outside of the major histocompatibility complex (n = 200) within these populations.

METHODS

Genotype data were available on 2652 Hispanics (1298 with MS, 1354 controls) and 2435 African Americans (1298 with MS, 1137 controls). We conducted single variant, pathway, and cumulative genetic risk score analyses.

RESULTS

We found less replication than statistical power suggested, particularly among African Americans. This could be due to limited correlation between the tested and causal variants within the sample or alternatively could indicate allelic and locus heterogeneity. Differences were observed between pathways enriched among the replicating versus all 200 variants. Although these differences should be examined in larger samples, a potential role exists for gene-environment or gene-gene interactions which alter phenotype differentially across racial and ethnic groups. Cumulative genetic risk scores were associated with MS within each study sample but showed limited diagnostic capability.

CONCLUSION

These findings provide a framework for fine-mapping efforts in multi-ethnic populations of MS.

OP0009 DERIVATION AND VALIDATION OF THE SCLERODERMA LUNG 3-STAGE INDEX (SL3SI), A NEW FUNCTIONAL INDEX FOR INTERSTITIAL LUNG DISEASE WITH PROGNOSTIC IMPLICATIONS

Background:

The staging of interstitial lung disease (ILD) is important to monitor disease progression and for prognostication. A disease severity scale of Systemic Sclerosis (SSc)-related lung disease has long been proposed (i.e. Medsger’s severity scale). This scale was mostly developed by discussion and consensus and stage thresholds were not computed by a data-driven approach. Hidden Markov models (HMM) are methods to estimate population quantities for chronic diseases with a staged interpretation which are diagnosed by markers measured at irregular intervals.

Objectives:

To build a SSc-ILD specific disease severity scale with prognostic relevance via HMM modeling.

Methods:

A total of 358 SSc patients at risk for or with ILD were enrolled in a discovery (207 cases, Milan1) and in a validation (151 cases, Milan2, Pavia and Rome) cohort. Patients were included if satisfied the following criteria: 1) Diagnosis of SSc according to the EULAR/ACR 2013 criteria, 2) absence of anticentromere antibodies, 3) dcSSc subset or 4) other subsets with either 4a) ILD-related antibodies (Scl70, PmScl, Ku) or 4b) evidence of ILD on HRCT, 5) disease duration < 5 years at the time of the first pulmonary function test (PFT). Serial PFTs were retrieved and the time up to the last available visit -if the patient alive-, or to death due to pulmonary complications, was recorded. HMM were used to estimate the threshold of a 3-stage model (SL3SI, Scleroderma Lung 3-Stage Index) based on PFT functional values (normal/mild, moderate, severe involvement) in the discovery cohort. Survival estimates of the SL3SI model were compared to Medsger’s severity classes estimates and their predictive capability evaluated via the explained residual variation (R2) of prediction errors (the higher the better). One-hundred random replicates were generated to simulate the prediction effort in patients with different disease duration and lung severity.

Results:

Patients characteristics are summarized in the Table. Fifteen-years survival estimates for Mesdger’s classes in the discovery set were: normal=0.88, mild=0.86, moderate=0.84 and severe=0.71. The SL3SI was defined by the following thresholds: normal/mild, FVC and DLco >=75%; moderate FVC or DLco 74-55%; severe, FVC or DLco <55%. SL3SI 15-yrs survival estimates were: normal/mild=0.89, moderate=0.82 and severe=0.63. Prediction analysis showed a higher R2values at 15 yrs for the SL3SI compared to Medsger’s classes, providing evidence for a better predictive capability of the former (discovery: 0.31 vs 0.25; validation: 0.28 vs 0.19).

Conclusion:

The SL3SI, a simplified 3-stage functional model of SSc-ILD, yields better survival estimates and long-term prognostic information than Medsger’s classes. Its reproducibility and ease of use make it a useful tool for the functional and prognostic evaluation of SSc patients at risk for or with ILD.

Table:VariablesDiscovery (n=207)Replication (n=151)DcSSc62 (30%)98 (64%)Age at first PFR48.6±1249.1±14.4Disease duration at first PFR1.7±1.61.3±2.4FVC90.5±18.191.1±20.2DLco70.7±19.861.3±20.1ILD on HRCT179 (86%)125 (80%)Scl70157 (76%)153 (78%)SSA63 (30%)32 (21%)n of visits38571473Follow-up time, yrs11±5.610.6±5.7Deaths27 (13%)23 (15%)

Disclosure of Interests:

Alessandro Santaniello: None declared, Chiara Bellocchi: None declared, Luca Bettolini: None declared, Marcello Cassavia: None declared, Gaia Montanelli: None declared, Adriana Severino: None declared, Monica Caronni: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Enrico De Lorenzis: None declared, Gerlando Natalello: None declared, Paolo Delvino: None declared, Claudio Tirelli: None declared, Lorenzo Cavagna: None declared, Giacomo De Luca Speakers bureau: SOBI, Novartis, Celgene, Pfizer, MSD, Silvia Laura Bosello: None declared, Lorenzo Beretta Grant/research support from: Pfizer

Microbiological survey of sugar gliders (Petaurus breviceps) kept as pets in Italy

The sugar glider (Petaurus breviceps) is a small, arboreal, nocturnal, gliding mammalian possum belonging to the marsupial infraclass. Exotic marsupials, including sugar gliders, are becoming popular companion pets and, consequently, the risk of potential infections that can be transmitted to humans should be investigated. Data on the role of the sugar glider as a possible carrier of pathogenic and zoonotic bacteria are scarce and fragmentary. Therefore, this study is aimed at evaluating the prevalence of potentially zoonotic bacteria (Salmonella spp., Escherichia coli, Campylobacter spp., Pseudomonas spp., Klebsiella spp., Listeria monocytogenes and Yersinia enterocolitica) in 64 sugar gliders kept as pets in Italy. The highest prevalence of infection pertained to members of the family Enterobacteriaceae, in particular Citrobacter spp. (50%), Enterobacter spp. (28·1%) and Klebsiella pneumoniae (15·6%); Pseudomonas aeruginosa was isolated from 10 out of 64 samples (15·6%). All strains of Klebsiella pneumoniae exhibited some level of resistance to multiple antimicrobials (ampicillin, amoxicillin-clavulanic acid and doxycycline). SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study show that sugar gliders may act as carriers of potentially pathogenic agents for humans and other animal species, therefore caution should be exercised in the handling and contact with these animals.

Hormone replacement therapy may prevent the development of isolated pulmonary hypertension in patients with systemic sclerosis and limited cutaneous involvement

BACKGROUND

Isolated pulmonary hypertension (iPHT) is a near-fatal consequence of systemic sclerosis (SSc); in female patients, the risk of its development is increased during the post-menopausal period, when the protective effects of oestrogens on the endothelium decrease. In many animal and human models, hormone replacement therapy (HRT) and oestrogen administration proved efficacious in counteracting many mechanisms that might be implicated in the pathogenesis of iPHT. Accordingly, it has been hypothesized that HRT might help to prevent the development of iPHT.

METHODS

A retrospective cohort study was conducted on 61 SSc patients with the limited cutaneous form of the disease and no sign of pulmonary hypertension on echocardiogram (pulmonary artery pressure, PAP > 35 mmHg) at the time of menopause. All the patients had to be stably treated with calcium-channel blockers and not to have risk factors for secondary PHT throughout the duration of the observational period.

RESULTS

Twenty patients (32.8%) received HRT for a mean of 6.7 +/- 3.7 years. None of these patients developed iPHT after a mean of 7.2 +/- 3.5 years from menopause, whereas eight out of 41 patients not receiving HRT (19.5%) developed iPHT after a similar time period (7.5 +/- 3.9 years, p = 0.032). These rates were not explained by differences between the two groups with respect to autoantibodies, age, age at onset of SSc, diffusing capacity of the lung for carbon monoxide (DLCO) at menopause, or duration of therapy with calcium-channel blockers.

CONCLUSION

HRT administration may be effective in SSc post-menopausal women, preventing the development of iPHT.

Presence of Shiga toxin-producing Escherichia coli O157:H7 in living layer hens

AIMS

To evaluate the presence of Shiga toxin-producing strains of Escherichia coli (STEC) of the O157:H7 serotype in living layer hens so as to analyse the role of this avian species as potential reservoir.

METHODS AND RESULTS

Cloacal swabs were collected between November 2004 and November 2005 from four intensive management layer hen farms and analysed for STEC O157:H7 by immunomagnetic separation methods and multiplex polymerase chain reaction for stx1 and/or stx2, the E. coli attaching and effacing (eae) and hly genes. STEC was detected in 26 of the 720 samples.

CONCLUSIONS

The layer hens analysed were shown to carry STEC O157:H7. The presence of this bacterium in living layer hen farms investigated did not result in any detectable increase in gastrointestinal disease in this species.

SIGNIFICANCE AND IMPACT OF THE STUDY

Living layer hens are a novel potential reservoir of E. coli O157:H7.

HLA-B35 upregulates the production of endothelin-1 in HLA-transfected cells: a possible pathogenetic role in pulmonary hypertension

HLA-B35 is associated with an increased risk for developing isolated pulmonary hypertension (iPHT) in systemic sclerosis, but the mechanisms underlying this association have not been fully elucidated yet. Endothelin-1 (ET-1) is the main pathogenetic molecule implied in the development of iPHT; therefore, we sought to determine if ECV304 cells transfected with the HLA-B35 allele produce increased amounts of ET-1 after incubation with physiological concentrations of interleukin-1 beta (IL-1beta). ECV304 cells transfected with HLA-B*3501 and HLA-B*0801 polymorphic alpha chain or with pIRESneo2 were incubated with 100 U/ml of IL-1beta for 6, 12, 24, 36 and 48 h. ET-1 levels were determined using EIA kit (CAYMAN Chemical, Ann Arbor, MI) in supernatants from different cell cultures; the relative expression of the preproendothelin-1 (PPET-1) gene was also determined by reverse transcription-polymerase chain reaction. Cells expressing the HLA-B35 allele showed significantly increased levels of ET-1 at all the selected times compared with controls or HLA-B8-transfected cells. The relative expression of the PPET-1 gene was also increased in a proportionally direct manner. The HLA-B35 allele influences the production of ET-1 in HLA-B35-transfected ECV304 cells by promoting the expression of its precursor, PPET-1. Our results provide an explanation for the epidemiological association existing between iPHT and HLA-B35.

Validity of the Saint George's Respiratory Questionnaire in the evaluation of the health-related quality of life in patients with interstitial lung disease secondary to systemic sclerosis

OBJECTIVES

Interstitial lung disease (ILD) profoundly affects the health-related quality of life (HRQoL) in patients with systemic sclerosis (SSc). We tested the validity of the Saint George's Respiratory Questionnaire (SGRQ), a lung-specific HRQoL-evaluation tool, in a population of SSc patients with ILD.

METHODS

Twenty-eight consecutive SSc patients with a restrictive pulmonary involvement, defined as a forced vital capacity <80% of the predicted, with no pulmonary hypertension were considered. All the patients filled in the Medical Research Council (MRC) scale for perceived breathlessness, the SGRQ and the Disability Index of the Health Assessment Questionnaire (HAQ DI), and underwent evaluation with complete pulmonary function testing (PFT), 6-minute walk distance (6MWD) and high-resolution computed tomography (HRCT).

RESULTS

The SGRQ 'activity' scores inversely correlated with the 6MWD (r = -0.86, P < 0.001) and forced vital capacity percentage of predicted values (r = -0.47) and directly correlated with HRCT (r = 0.41, P < 0.05), MRC (rho = 0.64, P < 0.001) or HAQ DI scores (r = 0.62, P < 0.001), independently of disease duration or subset. On the contrary, HAQ DI scores were influenced by those variables and corrected correlations with 6MWD (r = 0.56, P < 0.001) or HRCT scores (r = 0.36, P = NS) were less strong than those observed with the SGRQ.

CONCLUSIONS

The SGRQ, although not specifically designed for scleroderma, is a valid respiratory-specific questionnaire for the evaluation of HRQoL in patients with SSc-related ILD. The SGRQ performs better in relation to exercise capacity and lung imaging than other non-respiratory-specific questionnaires widely used in scleroderma studies. Further studies are needed to address its ability to assess changes over time or in response to therapy.

Open study on the antidiarrhoeal effectiveness of the L 105 compound

The therapeutical effectiveness of L 105, a new drug preparation exhibiting antidiarrhoeal activity and containing Rifaxidin, was tested on 22 patients with acute gastroenteric syndrome of bacterial aetiology. In all patients there was a prompt restoration of intestinal function by the 2nd treatment day. Both local and systemic drug tolerance proved to be good in all cases.