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The Root of Sinusitis

Sinusitis, also known as sinus infection, is a symptom caused by inflammation of the sinus mucosa. Common symptoms include snot, stuffy nose, and facial pain. Other signs and symptoms may include fever, headache, poor sense of smell, sore throat and cough. Sinusitis can be caused by infections, allergies, air pollution or structural problems in the nose. Most cases are caused by viral infections. However, its specific molecular mechanism is not known to us.

Recently, Emma Persson, Kenneth Verstraete and Ines Heyndrickx of the VIB Inflammation Research Center in Belgium found that the key to respiratory tract sinusitis, asthma and other respiratory allergic diseases is the protein crystals in the respiratory tract. The use of antibodies to dissolve these protein crystals can suppress dust allergen-induced airway inflammation. Protein is the cornerstone of the biological body, and various functions in the human body often require different proteins to complete. These proteins are normally dissolved in body fluids or bound to membrane structures such as cell membranes, and protein crystals are rarely formed. In 1853, Charcot and Robin discovered crystal deposits in the blood and spleen of a leukemia patient; in 1872, Leyden also found the same crystal in the sputum of asthma patients. Therefore, such crystals are also referred to as Charcot-Leyden crystals (CLCs). Studies have shown that the main component in CLCs is Galectin 10 (Gal10). Gal10 is a protein abundant in eosinophils and basophils, and its formation is closely related to the release of extracellular traps of eosinophils. In addition, CLCs have also been found in eosinophil-mediated inflammation such as chronic sinusitis and parasitic infections, as well as in eosinophil invasive tumors. This indicates the presence of CLCs in the presence of eosinophil-mediated inflammation sites. Clinical studies have found abundant eosinophils in allergic diseases such as asthma and chronic sinusitis. Further testing revealed that the structures of the crystals of Gal10 and CLCs were detected in tissues removed from patients with these diseases. To further validate the experimental results, Gal10 crystals, which are very similar to the CLCs obtained from patients, were synthesized. The researchers injected Gal10 crystals into the airways of mice. After a few hours, a large number of neutrophils and monocytes entered the mouse airway. These immune cells release a large number of inflammatory factors such as IL-6 and TNF-α in the airway of mice, and IL-1β and monocyte chemotactic factor CCL2 also appear in the lung. Interestingly, however, these pro-inflammatory effects do not occur in soluble Gal10 mutants.

Figure 1. Eosinophil extracellular trap release produces CLCs.

Since only Gal10 crystals can trigger these inflammatory reactions, if these crystals can be dissolved, can it alleviate the inflammation of chronic sinusitis, asthma and other diseases? The researchers developed an antibody 1D11 that can dissolve Gal10 crystals. 1D11 can dissolve Gal10 crystals within 2 hours, and can also dissolve CLCs crystals in mucus of patients with chronic sinusitis. In a mouse model of dust mite-induced asthma, 1D11-CLCs lysis treatment completely neutralized the pro-inflammatory effects of CLCs. Therefore, the use of these antibodies may be a very effective method to reduce excessive inflammation and mucus accumulation in the lungs of asthmatic patients. Since there is currently no drug for airway mucus accumulation, this research may change the way the disease is treated.