We also found that there was a highly significant good positive correlation between presence MRI brain black holes and brain atrophy and CSF level of CHI3L1, which might be explained by the diffuse neurodegeneration and axonal loss along with ongoing astrocytic and microglial activation results in higher levels of CSF CHI3L1 in progressive MS, which was confirmed by many previous studies [31, 38]. This evidence concerns the gene CHI3L1 and Brain atrophy.