Several studies demonstrate that the Nsp3 and the human poly‐adenosine diphosphate‐ribose polymerase 9 (parp9)10 and parp141 have identical residues that could produce molecular mimicry, leading to leukopenia and an altered inflammatory response.1, 10 This condition can be explained by a cytokine storm state, related to the macrophage activation syndrome (MAS).11, 12. This evidence concerns the gene PARP9 and macrophage activation syndrome.