A T-cell protein that sparks joint inflammation in rheumatoid arthritis

CD8 T cell derived Granzyme K activates complement that drives synovial fibroblast inflammation

NIH-funded research Brigham and Women's Hospital · NIH-11173621

Researchers are looking at whether a protein made by a type of T cell (granzyme K) turns on complement proteins that make the joint lining cells inflamed in people with rheumatoid arthritis.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionBrigham and Women's Hospital NIH-funded
Lab location1 site (Boston, United States)
Project IDNIH-11173621 on NIH RePORTER

What this research studies

This work looks at immune cells taken from inflamed joints and blood of people with rheumatoid arthritis to see how CD8 T cells release granzyme K and how that protein interacts with complement proteins made by joint-lining fibroblasts. The team measures whether granzyme K can cut complement components to create active fragments (like C3a/C3b) and whether those fragments make fibroblasts and mast cells more inflammatory. They use human synovial tissue and cells and build on mouse data showing complement can prime fibroblasts, aiming to connect the cell-level events to human disease. The goal is to map the pathway by which CD8 T cell signals could drive persistent joint inflammation.

Who could benefit from this research

Good fit: People with rheumatoid arthritis, especially those with active joint inflammation who can provide blood or synovial tissue samples, would be most relevant to this work.

Not a fit: People without rheumatoid arthritis or with noninflammatory joint conditions (for example plain osteoarthritis) are unlikely to benefit directly from this specific line of research.

Why it matters

Potential benefit: If confirmed, this could point to a new target to reduce harmful inflammation in rheumatoid arthritis and lead to new treatment strategies.

How similar studies have performed: Prior studies have shown complement can prime mouse synovial fibroblasts, but linking CD8 T cell–derived granzyme K to human complement activation and fibroblast inflammation is a relatively new finding under active study.

Where this research is happening

Boston, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.