title: A causal role for parvovirus B19 infection in adult dermatomyositis and other autoimmune syndromes.
abstract: BACKGROUND
  Infection with parvovirus B19 (B19) has been associated with connective tissue disease (CTD) stigmata, namely, a systemic lupus erythematosus (SLE)-like illness, seronegative polyarthritis resembling rheumatoid arthritis, and vasculitis. The dermatopathology and pathogenetic basis of such B19-associated CTD-like syndromes have not been elucidated.
  
  
  OBJECTIVE
  We attempted to document persistence of the B19 genome in skin lesions of 7 patients with CTD-like symptomatology following B19 infection and to correlate systemic manifestations to dermatopathological findings.
  
  
  METHODS
  In 7 prospectively encountered patients in whom history, clinical signs and/or serology supported a diagnosis of CTD in the setting of B19 infection, dermatopathological and clinical features were correlated. Parvovirus B19 viral genome was sought in skin tissue using the polymerase chain reaction (PCR).
  
  
  RESULTS
  Two patients had clinical features diagnostic of myopathic dermatomyositis (DM), 1 of whom is still symptomatic 1.5 years after the onset of her illness, and the other has had typical clinical features of DM for a duration of 3.5 years. A 3rd patient with SLE remains symptomatic 4 years after the onset of her illness. A 4th patient has persistent seronegative symmetrical polyarthritis of 6 years' duration and cutaneous lesions of granuloma annulare (GA). The 5th patient has a 1.5-year history of debilitating polyarthritis and cutaneous lesions with overlap features of DM and subacute cutaneous LE (SCLE). The 6th patient has had a persistent folliculocentric necrotizing vasculitis for 3 years. The 7th patient has a 1-year history of microscopic polyarteritis nodosa (PAN) with cutaneous vasculitis and persistent active renal disease. In 4 patients, exposure to children with fifth disease immediately preceded the onset of their CTD. Parvovirus B19 infection was documented serologically in 6 patients with antibodies of IgG subclass in 6 and of IgM subclass in 1. Four of 6 patients questioned had a history of atopy. Skin biopsies from patients with clinical features of SLE or DM demonstrated an interface dermatitis with dermal mucinosis. A necrotizing vasculitis with epithelial pustulation was seen in 2 patients. Interstitial GA-like infiltrates were seen in 5 cases. Immunofluorescent (IF) testing revealed a positive lupus band test (LBT) and epidermal nuclear and vascular staining for IgG and C5b-9 in the SLE patient. One DM patient had a negative LBT in concert with C5b-9 deposition along the dermoepidermal junction (DEJ) and within blood vessels while the other showed endomysial vascular Cs5b-9 deposition. In all patients, skin biopsy material contained B19 genome, which was absent in the serum of 4 patients analyzed. Symptomatic relief followed immunosuppressive and immunomodulatory therapy with agents including prednisone, cyclophosphamide, hydroxychloroquine, non-steroidal anti-inflammatory drugs and etanercept, but no patient has had complete symptom resolution.
  
  
  CONCLUSIONS
  Persistent B19 infection may be of pathogenetic importance in certain prototypic CTD syndromes, to which underlying immune dysregulation associated with a blunted IgM response to viral antigen may predispose. Anti-viral therapy might be worthy of consideration since traditional immunosuppressive therapy was unsuccessful in our cases.
authors: Central Medical Laboratories, Winnipeg, Canada.
authors: A N
authors: AN
authors: Crowson
authors: C M
authors: CM
authors: Magro
authors: M R
authors: MR
authors: Dawood
mesh_terms: D000328:Adult; D001327:Autoimmune Diseases / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D003882:Dermatomyositis / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D005260:Female; D005455:Fluorescent Antibody Technique; D016679:Genome, Viral; D006801:Humans; D008297:Male; D008875:Middle Aged; D010322:Parvoviridae Infections / Q000150:complications*; D016732:Parvovirus B19, Human / Q000235:genetics; D016133:Polymerase Chain Reaction; D013577:Syndrome