Preliminary Clinical Outcomes of Human Umbilical Cord Mesenchymal Stem Cell‐Derived Exosomes in Chronic Rhinosinusitis With Nasal Polyps: A Case Report

Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a persistent inflammatory disease that may be resistant to medical management and recurs with traditional surgery. We report a 28-year-old male with a history of CRSwNP with comorbid asthma, who was resistant to all medical management, including saline irrigation, intranasal corticosteroids (INCS), and multiple courses of antibiotics, and elected against surgical intervention. Nasal endoscopy and imaging studies demonstrated bilateral polyposis and opacification of the ostia of all sinuses (Meltzer score 5 and Lund-Mackay score of 18). Serum IgE level remained significantly high. The patient declined surgical intervention but consented to treatment with human umbilical cord MSC-Exo (hUCMSC-Exo) intramucosal and intrapolyp injections while continuing his standard regimen of saline irrigation and INCS. The treatment was well tolerated, with only reported mild and transient epistaxis. At follow-up after two months, the patient experienced a rapid decrease in SNOT-22 score (56-6). However, the symptomatic relief had abated, and the symptoms returned gradually but did not reach baseline (SNOT-22 increased to 41). Conversely, asthma control remained stable during this time, and the serum IgE level showed an overall negative trend. Given the single-patient, uncontrolled design with concurrent INCS and short follow-up, causality cannot be inferred. This case supports feasibility/tolerability and generates hypotheses for larger controlled studies of this cell-free approach.