Hélène Ruffieux, PhD

I am a Senior Research Fellow and Team Leader at the MRC Biostatistics Unit, University of Cambridge (United Kingdom). I hold a PhD in Mathematics from EPFL (Switzerland). My research lies at the intersection of statistical methodology and its application to open problems in biomedicine.

My team develops Bayesian methods and accompanying software, with a focus on scalable hierarchical modelling approaches for variable selection, latent structure discovery and network estimation, in high-dimensional or temporal data settings. Our methods are motivated by research questions arising from collaborative clinical and biological studies. Our overarching goal is to provide principled statistical and computational tools to help advance our understanding of the biological processes driving disease risk and progression.

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Current team

I have the pleasure of working with talented researchers at the MRC Biostatistics Unit:

  • Xiaoyue Xi, Research Associate;
  • Daniel Temko, Research Associate;
  • Camilla Lingjærde, Research Associate (co-advised with Sylvia Richardson);
  • Marion Kerioui, Research Associate;
  • Yiran Li, PhD Student (co-advised with John Whittaker).

I also regularly supervise Bachelor and Master theses of students from Cambridge University and EPFL (Lausanne), and I am a co-organiser of the MRC Biostatistics Unit Internship Programme.

Recent activity

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Mar 1, 2024: Our collaborative work, led by Dr Aimee Hanson, on how COVID-19 causes iron dysregulation early on in infection has now been published in Nature Immunology, with a preview here.

Jan 20, 2024: Our paper on the Joint Graphical Horseshoe with scalable expectation conditional maximisation estimation has now been accepted in the Annals of Applied Statistics – with Camilla Lingjærde, Benjamin Fairfax, Sylvia Richardson.

Nov 10, 2023: Invited seminar on “Bayesian joint functional principal component analysis (FPCA) for complex sampling designs”, at Imperial College London.

Nov 9, 2023: New preprint on Bayesian variational message passing for multivariate FPCA – with Tui Nolan and Sylvia Richardson.

Sept 6, 2023: New preprint on encoding auxiliary information to guide Bayesian network inference – with Xiaoyue Xi.

Research

The landscape of biomedical research is changing rapidly, driven by technological advances for quantifying clinical and molecular data at scale. This evolution not only offers a more granular view of disease mechanisms, but also parallels a growing acknowledgment that pathogenic responses are tightly coordinated at the organismal level. Consequently, there is a need for modelling approaches capable of providing a holistic understanding of complex interplays across biological systems.

My team aims to provide principled statistical methodology for tackling this challenge, guided by collaborations with clinicians and researchers in areas such as immunology, infectiology and cancer. Specifically, we develop Bayesian hierarchical modelling approaches for sparse regression, graphical modelling, latent factor modelling and functional data analysis to leverage complicated dependences within and between heterogeneous biological data sources (e.g., genetics, genomics, proteomics, metabolomics), while conveying uncertainty coherently.

We are particularly interested in addressing the tension between flexible joint estimation and practical feasibility for analysis at the scale of current biomedical studies, through dedicated efforts to enhance accuracy, robustness and computational tractability. Common threads for our methods include (i) uncovering and leveraging shared biological structures across multiple contexts (molecular entities, tissues, cell types or disease subtypes), and (ii) using approximate inference procedures, such as expectation-maximisation (EM) and model-specific variational schemes, tailored to the exploration of multimodal parameter spaces.

Our methods are designed with specific contexts in mind, yet are adaptable for various scientific applications, which is facilitated by accompanying statistical implementations (see Software).

Our research receives generous support from the Lopez–Loreta Foundation.

Short bio

Awards

Software & code

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atlasqtl

Variable selection in sparse regression with hierarchically-related responses

bayesFPCA

Bayesian functional principal component analysis suite – with Tui Nolan

book chapter on Bayesian variable selection

Source code for reproducing an example in a chapter published in the Handbook of Bayesian variable selection

covid patient trajectories app

FPCA estimates of patient disease trajectories after SARS-CoV-2 infection

covid recovery prediction app

Prediction of incomplete recovery from COVID-19

echoseq

Faithful replication and simulation of molecular and clinical data

epispot

Annotation-driven approach for large-scale joint regression with multiple responses

jointGHS

Joint graphical horseshoe for multiple network inference with shared information – creator and maintainer Camilla Lingjærde

locus

Large-scale variational inference for variable selection in sparse multiple-response regression

masterclass in variational inference

Solutions and suggested code for the 1st practical session fo the Bayes4Health-CoSInES Masterclass in variational inference – with Camilla Lingjærde

mQTL analysis example

Source code for reproducing a numerical example using the method “locus” on simulated data

navigm

Variable-guided network inference using Bayesian graphical spike-and-slab modelling – creator and maintainer Xiaoyue Xi

searchable pQTL database

Online database gathering hits from a QTL mapping of human protein abundance in plasma

sensitivity analysis for atlasqtl

Source code for assessing the sensitivity of the method “atlasqtl” to hyperparameter settings

software corner IBS bulletin

Source code for reproducing article on the atlasqtl R package published in the Software Corner of the IBS Bulletin

Contact