Development of a point-of-care test for the simultaneous detection of respiratory syncytial virus and IL-33 as a disease biomarker in children.

Purpose: The human respiratory syncytial virus (hRSV) is a leading cause of acute respiratory disease in children under 5 years of age. hRSV infection is associated with significant morbidity and mortality and represents a substantial economic burden for public health systems worldwide. Early and accurate diagnosis is critical for effective patient management, but current diagnostic tools, such as RT-qPCR, require specialized equipment and personnel. Further, currently available methods do not provide information regarding the prognosis of the disease caused by hRSV. Given this scenario, we aimed at generating and pre-validating a new rapid diagnosis test based on an immunochromatographic strip (ICS) to be used as a point-of-care (POC) test capable of simultaneously detecting the phosphoprotein P of hRSV (P-hRSV) and a biomarker of disease severity, interleukin-33 (IL-33) in nasal swabs.

Methods: Monoclonal antibodies against P-hRSV and IL-33 were produced and incorporated into an ICS. The 20-min rapid diagnostic test was evaluated and validated with recombinant proteins, virus-infected cells, viral dilutions, and hRSV-positive and negative clinical samples. Sensitivity and specificity were assessed.

Results: The ICS detected 103 pg of P-hRSV and as low as 187 PFUs of hRSV. Regarding recombinant IL-33, the ICS detected as low as 780 pg. The test strip exhibited high specificity, distinguishing hRSV from other respiratory viruses, including influenza and human metapneumovirus. Additionally, IL-33 was detected in some non-RSV infections.

Conclusions: The data obtained supports the feasibility of a combined rapid test detecting simultaneously hRSV and IL-33, which can be useful as a POC test for screening severe cases of hRSV in primary care settings and emergency rooms.