Overview of dry syndrome Dry syndrome is a chronic autoimmune disease that mainly invades exocrine glands such as lacrimal gland and salivary gland, also known as autoimmune exocrine gland disease. The disease has a high incidence and mostly occurs in women over 40 years old. Then, what are the causes of the onset of dry syndrome? The following are the causes of the onset of dry syndrome. 1.Genetic basis: In the research and determination of immunogenetic, medical doctors found that among human leukocyte antigens, HLA-DR3 and B8 are closely related to dry syndrome, and such relatedness is different according to the race, such as Western Europeans are related to HLA-B8, DR3 and DW52, and Japanese are related to HLA-DR53. -DR53, which indicates that dry syndrome has genetic tendency. 2.Viral infection: At present, at least three viruses such as EBV, cytomegalovirus and HIV are considered to be related to dry syndrome, and EBV can stimulate B cell proliferation and produce immunoglobulin. Some medical practitioners have detected EBV and its DNA gene in salivary gland, lacrimal gland and kidney specimens in patients with primary dry syndrome. (1) EBV primary EBV infection often invades the parotid gland, but SS does not occur at that time; however, EBV can be cultured in parotid fluid from 50% of patients with SS (compared to 20% of normal subjects). The increase in EBV DNA in the parotid gland of patients indicates that the virus is activated, but this phenomenon is also seen in other immune disorders and is not unique to SS disease. Therefore, EBV is not the direct cause of SSD, but rather acts as a polyclonal B-cell activator that may perpetuate or exacerbate the immune disorder in SS patients. 2) HIV-1 virus Human immunodeficiency virus HIV-1 infection can produce dry mouth, dry eyes, but differs from SS in that the parotid gland is highly enlarged, CD8+ rather than CD4+ lymphocytes invade the tissue, and autoantibodies (RF, anti-SS-A antibodies, anti-SS The frequency of autoantibodies (RF, anti-SS-A antibodies, anti-SS-B antibodies, anti-nuclear antibodies) was not increased and was associated with HLA-DR5 and DR6 rather than DR3 and DR2. However, serum reactivity with HIV protein-P24 was increased in SS patients. (3) HTLV-1 (human T-lymphotropic virus) infection can cause dry mouth, dry eyes and adult T-lymphocytic leukemia. (3) Autoimmunity: A variety of autoantibodies such as anti-nuclear antibody, rheumatoid factor, anti-RNP antibody, anti-SSA antibody, anti-SSB antibody, etc. and hyperglobulinemia are detected in patients with dry syndrome, reflecting the highly hyperfunctional B lymphocytes themselves and low inhibitory function of T lymphocytes. In addition, changes in the T-lymphocyte subpopulation of the disease, i.e., decreased suppressor T cells, reflect abnormalities in cellular immunity.