In a previous study, incubation of E. cuniculi spores with trypsin was shown to have impact on their virulence [41], so it may be proposed that the increasing levels of host enzymes of the serpin family, like alpha-1-antiproteinase precursor and alpha-1-antiproteinase, may play a role in the in vivo regulation of the inflammatory response during encephalitozoonosis in rabbits. This evidence concerns the gene SERPINA1 and encephalitozoonosis.