Diagnostic ability of myxovirus resistance-A in pediatric cases of viral-acute respiratory tract infections with vitamin A and zinc deficiencies

Acute respiratory tract infection (ARTI) rank among the top ten most common illnesses affecting children in Indonesia. Myxovirus resistance-A (MxA) protein, selectively induced by the activation of type I interferon in response to viral infections, has emerged as a promising biomarker to diagnose viral ARTI. Notably, the activation of interferons is thought to be influenced by plasma vitamin A and zinc levels. Therefore, our study aims to investigate the level of MxA expression in children with vitamin A and zinc deficiencies when experiencing viral ARTI. This cross-sectional study involved a total of 113 subjects, including 53 diagnosed with ARTI due to viral causes based on validated clinical scoring criteria, and 50 healthy controls. To determine the etiology, we conducted blood cultures and employed RT-PCR analysis on nasopharyngeal swabs. Additionally, we assessed plasma levels of vitamin A, zinc, and MxA protein expression. Our findings revealed that subjects with ARTI displayed elevated MxA expression compared to controls. Specifically, MxA expression levels in ARTI cases of viral origin were significantly higher than those in both control and bacterial origin. On closer examination, the vitamin A and zinc non-deficient group exhibited higher MxA expression levels in comparison to the deficient group. However, it is notable that the expression levels in the deficient group remained higher than those in the control group. In summary, MxA protein expression was found to be lower in children with vitamin A and zinc deficiencies when compared to those without deficiencies in cases of viral ARTI. Thus, MxA expression may serve as a diagnostic tool for distinguishing viral from bacterial ARTI, especially in populations where the prevalence of micronutrient-deficient children is high, such as in Indonesia.