We finally performed protein and nucleic acid in situ imaging (PANINI)58 to visualize the messenger RNA of a complement marker, C1QA, the neutrophil marker CD15 and the macrophage marker CD68 on COVID-19 tissue microarray sections to experimentally validate the spatially resolved gene-expression patterns predicted by MARIO (Fig. 5h). The gene discussed is FUT4; the disease is COVID-19.