ELISA assays for cytokine and IgA levels
TNF-α
SECONDARY
Other secondary outcomes including (i) pro-inflammatory cytokine levels (pg/mL) of interleukin (IL-6, IL-8) and TNF-α, and (ii) IgA levels (mg/mL) in nasopharyngeal samples at days 0 and 2 were quantified using an enzyme-linked immunosorbent assay kit (ELISA). IL-6 and TNF-α were quantified from 100 µL samples by the Human IL-6 DuoSet ELISA and the Human TNF-α ELISA kit, respectively (R&D Systems, MN, US). IL-8 was quantified by 50 µL samples by IL-8 Human ELISA kit (Invitrogen/Thermo Fisher Scientific, MA, US). IgA was quantified by 10 µL samples by Human IgA ELISA kit (Invitrogen/Thermo Fisher Scientific, MA, US).