Table 3.

Main viruses involved in the pathogenesis of pSS.

Virus	Genetic material	Targeted cells	Circumstances of activity and main diseases
EBV	DNA	B cells	Sialadenitis Reactivation in immunocompromised subjects—PTLD, hepatitis Mononucleosis Nasopharyngeal cancer Burkitt’s lymphoma Oral hairy leukoplakia Hodgkin disease (non-related and related to HIV)
CMV	DNA	Epithelial cells, endothelial cells, fibroblasts, and smooth muscle cells	Mononucleosis-like illness Severe complications in immunocompromised subjects including patients with AIDS: CMV-organ disease (retinitis, esophagitis, colitis, pneumonitis, hepatitis)
HTLV-1	RNA	T cells	Adult T cell leukemia, HTLV-1-associated myelopathy
HIV	RNA	T cells, macrophages, and dendritic cells	Flu-like symptoms (acute infection) asymptomatic stage (chronic infection) AIDS with opportunistic infections
HCV	RNA	Hepatocytes, dendritic cells, and B cells	Sialadenitis, chronic hepatitis, cirrhosis, hepatocellular carcinoma, extrahepatic manifestations (organs and systems involvement)
HBV	DNA	Hepatocytes	Acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma, Acute necrotizing vasculitis—polyarteritis nodosa (circulating immune complexes)* Other extrahepatic manifestations (organ and system involvement)
pB19	DNA	EPCs	In children: erythema infectiosum, thrombocytopenia, ITP In adults: arthralgia, arthritis, anemia, neutropenia, thrombocytopenia

AIDS, acquired immune deficiency syndrome; EBV, Epstein–Barr virus; EPCs, erythroid progenitor cells; CMV, cytomegalovirus; ITP, idiopathic thrombocytopenic purpura; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; HTLV, human T-lymphotropic virus; pB19, parvovirus-19; PTLD, post-transplant lymphoproliferative disease.