Diagram of T Cells Attacking Proliferating Cancer Cells
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Our immune system constantly targets cells considered threats. However, when rogue immune cells attack our own body, it leads to autoimmune disorders. Current treatments can suppress these attacks but don’t prevent them. Fortunately, innovative therapies that eliminate rogue cells are proving to be highly effective.
According to Reuben Benjamin from King’s College London, “All major pharmaceutical companies are now investing in this approach.” He notes that there are numerous clinical trials in progress, with potential approvals as early as next year, as these new treatments show improved efficacy over existing options.
The cornerstone of these advances is the use of genetically engineered CAR T cells. These specialized T cells typically destroy cells infected by bacteria or viruses. For this innovative therapy, T cells are extracted from patients, engineered to target specific cells, and reintroduced into their bodies.
Initially developed for cancer treatment, CAR T cells have shown remarkable success in curing individuals when all other therapies have failed. However, they primarily work against blood cancers like leukemia and come with significant side effects, including brain inflammation that can impact language and behavior.
Both cancer and autoimmune diseases result from mutated cells that evade normal growth controls. Autoimmune conditions occur when rogue immune cells mistakenly attack healthy tissues. For instance, type 1 diabetes arises from immune assaults on insulin-producing pancreatic cells, and multiple sclerosis results from attacks on the myelin sheath surrounding nerves. “The list of autoimmune diseases is extensive,” states Benjamin.
After exposure to infection, the body generates new immune cells, which undergo screening to eliminate self-reacting cells. However, in some cases, this process fails, allowing rogue cells to persist indefinitely.
Recent research has confirmed that mutations in critical genes may hamper this screening process, preventing self-destructive mechanisms. Essentially, autoimmune disorders resemble cancer more closely than previously understood.
Despite this similarity, it remains ambiguous whether CAR T cell therapies effective against cancer would also work for autoimmune diseases. A significant challenge lies in differentiating rogue immune cells from normal ones, necessitating the destruction of most antibody-producing cells—not solely the rogue ones.
In cancer patients, CAR T cells can persist for years; however, for autoimmune conditions, they might compromise immunity. Yet, using CAR T cells for autoimmune disorders has shown promising results, with less risk of severe side effects compared to cancer treatments.
“Miraculous” Results
Five years ago, Fabian Muller and his team at Erlangen University Hospital in Germany began treating lupus patients with CAR T cells. Müller noted, “The initial patients were critically ill and would have perished without treatment.” To their astonishment, CAR T cells effectively diminished symptoms, allowing the immune system to recover.
Muller attributes this success to the intact immune systems in autoimmune patients, which recognize CAR T cells as foreign and eliminate them after a few months, unlike patients with weakened immunity from cancer.
Despite potential risks, treatments show promise in managing autoimmune disorders. While many patients with cancer experience severe side effects, lupus patients treated with CAR T cells often do not. “It’s genuinely a miracle,” Muller remarked, anticipating this therapy might extend beyond the most severe cases.
He presents three reasons for these unexpected outcomes: CAR T cells destroy fewer cells in autoimmune patients than in advanced cancer patients; the quality of CAR T cells in autoimmune cases is generally higher; and overactive immune responses in cancer patients may lead to excessive CAR T cell reactions.
Globally, hundreds of patients are currently being treated with CAR T cells for autoimmune diseases. Although definitive trial results are pending, initial reports indicate significant effectiveness against disorders like lupus, myasthenia gravis, and ulcerative colitis. While doctors remain cautious not to label it a “cure,” successful elimination of rogue cells holds the possibility of long-lasting relief.
According to Benjamin, “In the world of cancer, we often wait five years to discuss potential cures. In the realm of autoimmunity, the answer is still unclear.” Yet, if rogue cells emerge again, re-treatment could be an option.
Nonetheless, caution is advised. The damage inflicted by self-targeting immune cells may not be reversible, and not all rogue cells are easily identified or targeted. Furthermore, the cost of CAR T cell therapy poses a significant hurdle for widespread adoption—harvesting, modifying, and reinfusing personal cells can be prohibitively expensive.
On a positive note, researchers are developing so-called off-the-shelf CAR T-cell therapies for broader application. These use donor T cells to treat multiple patients, which could address some logistical challenges posed by current methods. While commercially available CAR T cells have had limited success in cancer treatment, their stability in autoimmune patients could offer advantages.
Additionally, innovations in “in-vivo CAR T cells” create CAR T cells within a patient’s body rather than in a lab, streamlining production and potentially reducing costs. “We’re genuinely excited about this,” Benjamin concludes.
While challenges may emerge down the line, the progress made in using CAR T cells for autoimmune disorders surpasses expectations from just five years ago. This development is promising news for the approximately one in ten individuals affected by such conditions.
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Source: www.newscientist.com
