Detecting T Cell Dysfunction in Post-Acute Infection Syndromes

At IDWeek, Nigel McCracken, PhD, COO of Virax Biolabs, discussed their work on developing a diagnostic test for early detection of T cell dysfunction in post-acute infection syndromes like Long COVID, chronic fatigue syndrome, and Lyme disease. The test aims to identify T cell exhaustion by measuring cell surface markers and cytokines released by B and T cells. Early detection could enable better treatment management, including lifestyle changes and antioxidants, before symptoms become irreversible. The test could also differentiate between symptoms caused by post-acute infections and those requiring specific treatments for conditions like depression and anxiety.

Focusing on the implications of viral infections such as SARS-CoV and RSV. He explained the significance of these conditions, stating, “We’re speaking to investigators and clinicians around post-acute infection syndromes. We’ve obviously heard about SARS-CoV-2 and RSV. The viral infections themselves actually do cause problems afterwards. And we know, and we’ve heard about Long COVID; we know things about chronic fatigue syndrome, or even post-acute Lyme disease. The symptoms, if you leave them long enough, are all the same.”

McCracken emphasized the importance of developing diagnostics to identify early signs of T cell dysfunction, which he believes plays a significant role in the symptoms associated with these syndromes. “What we’re trying to do is basically try and develop a diagnostic to identify the early signs of T cell dysfunction, because we believe that the dysfunctional immune system plays quite a big role in a lot of the main symptoms associated with post-acute infection syndromes like Lyme disease as well as Long COVID,” he noted.

He explained the two types of immune responses: innate and adaptive. “There’s an innate immune response, which is a quick response, and then there’s an adaptive response. The adaptive response is more focused, involving B cells that form antibodies and T cells that are cytotoxic, meant to kill the virus and remove it from the body.”

Nigel elaborated on their work in developing diagnostics for T cell dysfunction. “What we’re wanting to do is look at some of the markers, the proteins that are released, cytokines, as we call them, and see if there is a signature related to an exhausted or dysfunctional T cell.” He pointed out that T cell dysfunction is not a new concept, noting its relevance in oncology.

McCracken explained that their test aims to identify T cell dysfunction early, before it becomes irreversible. “We hope to be able to identify that early to allow treatment management. There are no drugs specifically at this moment, but drug companies are working on Long COVID treatments. Meanwhile, we can focus on lifestyle changes or dietary adjustments, such as antioxidants, to reduce chronic inflammation.”

He acknowledged the complexity of symptoms associated with post-acute infections, highlighting the connection between chronic fatigue and cognitive impairment, as well as anxiety and depression. “Although chronic fatigue and cognitive impairment are the main symptoms, there are also things like anxiety and depression associated with conditions like Long COVID.”

McCracken described the lengthy journey many Long COVID patients experience. “The journey of a Long COVID patient is long. It can be up to 18 months. You’re going to get tested for many things. Most of the diagnosis is self-diagnosed. I think anyone who can understand what’s causing the problem can help address it.”

He noted that chronic inflammation plays a role in the response to viral infections. “You need chronic inflammation to create an environment to get rid of a virus, but you don’t want it to last for a long period. There are things we can do to reduce chronic inflammation, like lifestyle changes and antioxidants.”

Reflecting on the broader implications of these conditions, Nigel expressed hope that the increased awareness surrounding Long COVID could benefit others suffering from chronic conditions. “I think the whole thing around Long COVID has helped patients who have dealt with chronic fatigue syndrome for years. It has brought attention to a general problem around chronic inflammatory conditions. We really need to do something about it, as it is causing a huge healthcare problem and a significant burden on society.” This discussion underscores the need for ongoing research and innovation in understanding and managing post-acute infection syndromes, particularly in the context of emerging viral infections.

Watch our latest roundtable series to learn more about Long COVID: A Deep Dive: Understanding the Neurological Toll of Long COVID