Subretinal MCMV inoculation of mice with MAIDS who were also genetically deficient in either IL-4 (IL-4 −/− mice) or IL-10 (IL-10 −/− mice) production showed equivalently high intraocular amounts of infectious virus as well as equivalent susceptibility to MCMV retinitis when compared with wildtype mice with MAIDS [66]. This evidence concerns the gene IL4 and retinitis.