CIRCULATING EXOSOMAL CD30 AND CD79B IN DIFFUSE LARGE B-CELL LYMPHOMA PATIENTS

Purpose: Up to 30-40% of patients do not respond to treatment or relapse after R-CHOP chemoimmunotherapy in DLBCL. The predictive biomarkers for identifying candidates for new therapies have not been extensively studied. We aimed to determine the presence of CD3, CD19, CD20, CD30 and CD79B in plasma-derived exosomes from DLBCL patients and to compare the profiles of target proteins in exosomes and matched primary tumour tissue. Materials and Methods: Exosome samples from 20 newly diagnosed DLBCL patients and 20 healthy controls from our previous studies were characterized according to the recent MISEV2018 guidelines. The presence of targeted antibodies in exosomes was determined by Western Blotting, while their expression in primary tumour tissue was analysed by immunohistochemistry. Results: CD30-positive exosomes were detected in the blood of 17 patients (85%), whereas CD30 expression in tumor cells was observed in only 2 patients (10%). Evaluation of CD79B expression in tumor cells was limited to 6 patients. Conclusion: In addition to tumor cells, characterising the factors present in the tumor microenvironment that support tumor cells, such as exosomes, will increase our success in treating DLBCL. Preclinical and clinical studies are needed to evaluate the presence of circulating CD30-and CD79B-positive exosomes in the selection of candidates for targeted immunotherapies using a non-invasive approach..