Parvoviral infection of endothelial cells and its possible role in vasculitis and autoimmune diseases.

OBJECTIVE: To analyze a series of biopsies from 16 patients who, on the basis of clinical and dermatopathologic findings, had a spectrum of connective tissue diseases (CTD), autoinflammatory or CTD-like syndromes for parvoviral DNA, RNA, and protein.
METHODS: Most of the patients were initially screened for parvoviral-related IgG and IgM antibodies. Parvoviral DNA was analyzed by solution phase polymerase chain reaction (PCR). In situ localization of viral VP1 RNA was accomplished by in situ reverse transcriptase (RT) PCR; viral protein (VP2) was detected by immunohistochemistry and these results correlated with the histologic findings. (J Rheumatol 2002;29:xxxx)
RESULTS: Of 11 people tested, 10 had either IgG or IgM specific antibodies against parvovirus. Common histologic features of the 16 cases included an interface dermatitis, interstitial histiocytic infiltration with variable collagen necrobiosis, a mononuclear cell dominant vasculitis, and interstitial neutrophilia. Detection of parvoviral RNA by in situ RT-PCR in 14 of 16 cases corroborated solution phase PCR data and demonstrated that the endothelial cells and surrounding mononuclear cells were the viral target. Viral protein as revealed by immunohistochemisty showed an equivalent histologic distribution. Anti-tumor necrosis factor-alpha (TNF-alpha) therapy (etanercept) yielded dramatic improvement after worsening of symptoms with traditional immunosuppressive therapy in the 3 patients in whom this drug was administered; TNF-alpha mRNA was detected by in situ RT-PCR in the area of parvoviral infected cells.
CONCLUSION: Parvoviral induced endothelialitis may be responsible for cases of "idiopathic" CTD.