How can we determine course and severity of asthma by examination of easy-to-reach patient biosamples? This question is in focus of the ALLIANCE registry. A part of the answer: Drawing blood from patients and evaluate specific microRNAs. The results of this study have been published online in the scientific journal Allergy.
Asthma is a chronic disease with numerous courses from infancy until adulthood. Therefore, clinicians need tools to predict, if a child will develop severe asthma or if the symptoms will vanish without medical interference. In order to improve diagnosis of asthma, the DZL established the longitudinal All Age Asthma Cohort ALLIANCE in which also BREATH scientists take part. By now, it comprises clinical data and biomaterials of more than 1.000 participants. ALLIANCE also aims to improve the understanding of molecular and cellular basics for initiation of the disease. This could finally lead to new starting points for asthma therapy.
In the study published two days ago, DZL scientists investigated microRNAs (miRNAs) from blood of study participants. miRNAs are short nucleic acid fragments employed by cells for communication. They are packed into extracellular vesicles and secreted in the blood. Target cells take up the vesicles and release the miRNAs intracellularly. They bind to complementary nucleic acids and thereby regulate specific cellular processes such as immune responses, metabolism or cell growth.
In this project of the ALLIANCE study, scientists compared the miRNA repertoire from blood of asthma patients and healthy donors. And in fact, they found differences: Especially miR-122-5p concentration was increased in blood plasma of asthmatics. The same difference showed up in sputum samples. Among all blood samples, three miRNAs (including miR-122-5p) correlated with lung function parameters or with the number of particular immune cells. A network analysis showed that the miRNAs might be linked to development and function of lymphocytes. In future, they might be used for discrimination of subtypes like eosinophilic or neutrophilic asthma. Leading author Dr. Sabine Bartel comments: „This is the first study showing a difference in miRNA levels in extracellular vesicles from plasma of asthma patients.” Another premiere: This article, published online in Allergy, is the first to present results from biomaterial collection of the adult arm of the ALLIANCE registry. It is planned to verify the findings with a higher number of samples and to look at further asthma subtypes.