A recent study by Trinity College Dublin researchers published in the journal Allergy examines chronic spontaneous urticaria (CSU), a common skin condition characterized by recurring hives. This study is the first of its kind to demonstrate a connection between rare cell types and the response to treatment. Professor Niall Conlon, Clinical Professor at the School of Medicine and Consultant Immunologist at St. James’s Hospital, led the study.Ireland’s only UCARE centre for urticaria management is led by the Medical Specialist and Clinical Lead who headed the research team.
Chronic spontaneous urticaria (CSU) is a common but underreported disease, where individuals develop recurring, unpredictable, and intensely itchy hives and skin swellings with no clear trigger. The UCARE centre at St. James’s Hospital sees 10-20 new patients with CSU per week. Although CSU shares some symptoms with food allergy, it is not caused by an allergy to food or medications. Diagnosis of CSU can be delayed and challenging due to a lack of awareness about the condition. Additionally, individuals with this disease can suffer greatly from the impact.The study investigated a type of mast cells known as myeloid progenitors in the blood of patients with chronic spontaneous urticaria (CSU). The team compared these cells in individuals with CSU and those without the condition. They also looked at how well patients responded to the anti-IgE therapy omalizumab. The study found that individuals who responded quickly to omalizumab had higher levels of myeloid progenitors in their blood, compared to those who had a slower or no response to the treatment. This suggests a potential link between myeloid progenitors and treatment response in CSU patients.The research suggests the potential use of these cell types to predict the response to anti-IgE therapies. Dr. Barry Moran, a scientist at Trinity Biomedical Science Institute (TBSI), Trinity College, who was involved in the study, stated that they have developed a flow assay to identify this rare cell type. He also expressed excitement about how their findings and clinical correlates were supported by transcriptomic data. David McMahon from the Irish Skin Foundation explained that CSU refers to hives that appear and disappear without a specific trigger and last for longer than 6 weeks. This information could be helpful for some individuals.The impact of CSU on quality of life can be substantial and widespread. CSU is often misinterpreted as an allergic reaction, leading people to search for specific triggers such as food allergies. However, avoiding suspected triggers does not provide relief, which can be frustrating for those affected by the condition. While many individuals can effectively manage their symptoms with regular use of high-dose antihistamines, some may require referral to a specialist if they do not respond to this treatment.The UCARE centre in St. James’s Hospital is a specialized facility for individuals seeking treatment for chronic urticaria. If high dose antihistamines prove ineffective, patients may be considered for the anti-IgE biologic treatment, omalizumab, which is only available in specialized settings.
Dr. Conor Finlay, a scientist at the Trinity Translational Medicine Institute (TTMI) and one of the study’s senior authors, explained:
“When activated by IgE antibodies, mast cells release inflammatory factors into the skin, causing itching and hives.”
Dr. Niall Conlon, a senior author on the study and consultant immunologist, emphasized the importance of this research.
Dr Katie Ridge, the lead author on the study, mentioned that while omalizumab works well for some people in stabilizing mast cells, it is less effective or takes longer to work for others. Understanding why certain individuals do not respond well to omalizumab could help in directing treatments more effectively and improving patient outcomes. Ridge added that studying mast cells is challenging since mature mast cells are not present in the blood, which is why they used an alternative method for their research.
A very uncommon type of immature mast cells, known as mast cell progenitors, has been discovered in the blood. This discovery suggests that there may be inflammatory signals involved in chronic urticaria and emphasizes that this condition goes beyond the surface of the skin. The implications of these findings are significant, not only for individuals with urticaria, but also for potential treatment responses in other allergic diseases. Research on this type of cell may help predict how patients will respond to treatment.
