We can reasonably infer that, on one hand, the autoimmune disease can attack the lacrimal gland tissue via immune reaction to achieve the reduction of the tear secretion; on the other hand, the autoimmune disease can attack the ocular surface epithelial cells and promote the ocular surface inflammatory reaction to cause the damage of accessory lacrimal glands and goblet cells and promote the occurrence and growth of ocular surface inflammatory reactions and result in the damage of ocular surface epithelial cells and the reduction of mucin secretion. Here, MUC5AC is linked to autoimmune disease.