History of BILAG

In 1983, in a rose garden in Birmingham, Paul Bacon and Mike Snaith discussed a shared frustration: the global disease activity scores available for systemic lupus erythematosus (SLE) were limited. They failed to adequately reflect the complexity, heterogeneity, and organ-specific nature of lupus, and were insufficiently sensitive to change over time.

To address this, Paul and Mike joined forces with David Isenberg, Peter Maddison, Asad Zoma, Caroline Gordon, Deborah Symmons, and Elaine Hay to form what became the British Isles Lupus Assessment Group (BILAG).

Their aim was ambitious: to create a disease activity measure that:

• Captured activity across individual organ systems
• Reflected different levels of severity
• Was sensitive to change over time
• Was grounded in the physician's intention to treat

The BILAG Index was first presented at the International Lupus Meeting in Calgary in 1986 and formally described in 1988. Its organ-based structure represented a fundamental shift in how lupus activity was conceptualised and measured. The subsequent refinement into the BILAG-2004 Index further strengthened its validity, reliability and clinical utility.

Today, BILAG-2004 remains one of the most comprehensive organ-based lupus activity indices and continues to underpin contemporary clinical trials and translational research worldwide.

Four Decades of Impact

Over the following 40 years, BILAG evolved from an index development group into a nationally and internationally recognised collaborative network advancing lupus care across multiple domains.

Key contributions include:

• Development of SLE quality-of-life measurement, including LupusQoL
• Investigator-initiated clinical trials (including CsA vs AZA, USEFUL, and BEAT-LUPUS)
• Large-scale real-world evaluation of biologic therapies through the BILAG Biologics Register (BILAG-BR)
• Collaborative translational research programmes such as MASTERPLANS
• Innovation in disease activity capture, including EASY-BILAG

The first British Society for Rheumatology guideline on SLE, led by Caroline Gordon in 2017, marked another milestone in UK lupus care. In 2026, BILAG presents an updated BSR SLE guideline with unprecedented detail and scope, embracing a whole life-course approach to lupus management.

Under the current chairmanship of Ed Vital, BILAG remains committed to:

• Improving the care and quality of life of people with SLE
• Developing and promoting best practice in disease activity and outcome measurement
• Fostering collaborative research and innovation
• Serving as the steering group for the BILAG Biologics Register
• Developing the next generation of clinical and academic lupologists

Current randomised controlled trials include FIRST (investigating first-line rituximab) and STRATIFY-LUPUS (investigating combination rituximab and belimumab with biomarker stratification).

Digital Evolution

In 2026, BILAG entered a new phase of digital transformation with the development of EasyBILAG-Digital, a next-generation platform designed to preserve the integrity of BILAG-2004 while improving usability, speed, structured assessment and data capture in both clinical practice and trials.

This digital evolution reflects the original founding philosophy: rigorous measurement, grounded in clinical intent, adapted to contemporary practice.