Past and present: Henry G. Kunkel and the Rheumatoid Factor

There are names that do not appear every day in medical consultations or clinical reports, but without them, modern medicine would not be where it is today.

Henry G. Kunkel is one of them: a brilliant researcher, mentor to generations of scientists, and a key figure in understanding the true meaning of the rheumatoid factor and its role in autoimmune diseases.

Beyond awards and recognitions, Kunkel left something even more precious: a way of interpreting science with rigor, curiosity and strong clinical insight.

Keep reading to get to know this science-driven genius a little better.

Rockefeller University was where Kunkel developed most of his scientific career. His laboratory became a meeting point for researchers and internationally renowned scientists, as well as a place frequently visited by former students, fellows and collaborators.

They all agreed on two things: Henry was a simple man, uninterested in luxury, and someone who didn’t just analyse data — he thought about it. He wanted to understand what lay behind every result and how those findings could shape the future understanding of disease.

Always passionate about discussion, he enjoyed exploring and solving the enigmas raised by new experimental data.

And best of all, he often said goodbye with the same words: “Come again.”

But what truly matters to us today is how Kunkel became a pioneer in rheumatoid factor research. This is more important than it may sound, because it changed the way we understand rheumatoid arthritis (RA): both technically and conceptually.

But first things first…

In simple terms, rheumatoid factor is an antibody that can bind to other antibodies, forming immune complexes.

For many years, RF was almost exclusively associated with rheumatoid arthritis. However, in the 1950s, Kunkel and his team demonstrated several key concepts:

• RF is not exclusive to rheumatoid arthritis.
• It can appear in other autoimmune diseases, chronic infections, and even in healthy individuals.
• Clinical context is essential for interpreting its presence.

Kunkel’s work showed that the immune system can generate responses that, instead of protecting the body, perpetuate inflammation and tissue damage.

He and his team concluded that RF is not just a “marker”, but an antibody directed against antigen–antibody complexes.

This new interpretation made it easier to understand the pathogenesis of RA and opened the door to a more complex and integrated vision of rheumatic diseases.

More than 70 years have passed since Kunkel made his groundbreaking discoveries. While we now have more specific biomarkers, rheumatoid factor remains clinically relevant. Why?

• It helps with diagnosis and patient stratification.
• It is associated with more severe disease forms.
• It remains a key part of rheumatology history and education.

RF is no longer seen as a simple laboratory value, but as a meaningful piece within a dynamic and complex immune system.

Like many other figures who became references in science and medicine, Henry Kunkel’s legacy reminds us how much we owe to those who came before us.

Not only to him, but to all researchers who teach us to look beyond established knowledge — to think critically, ask questions, and connect two worlds that were once seen as separate: basic research and clinical practice.

As strong advocates for medical education and the healthcare ecosystem, at CMC we recognise the value of every professional who contributes to advancing knowledge. Henry Kunkel’s legacy is particularly inspiring.

Knowledge moves forward when we share ideas, discuss them and place them in context.

His story reminds us that simple questions, clinical observation and perseverance are three pillars capable of changing medicine.

At CMC, we develop educational programs for rheumatologists and specialists across many other therapeutic areas, always grounded in scientific evidence. We strongly believe in the impact of experts and in the importance of key opinion leaders in continuing medical education.

That’s why we invite you to discover our programs.

Keep learning with us.

And keep asking questions — to help medicine move forward.