Parvovirus B19 and systemic sclerosis

We read with great interest the recent article by Ohtsuka and Yamazaki reporting a significantly higher prevalence of parvovirus B19 (PV-B19) infection of the skin in patients with systemic sclerosis (SSc) compared with normal subjects and those with other immune-mediated disorders. This report further supports our previous studies suggesting a possible role of PV-B19 in the pathogenesis of SSc We would like to summarize our latest observations on this intriguing subject. Given the possible association of PV-B19 with some rheumatic disorders and its tropism for haematopoietic tissue in 1999 we first demonstrated a significantly higher prevalence of PV-B19 DNA in bone marrow biopsies from unselected patients with SSc compared with controls. Bone marrow may represent a reservoir from which the virus could spread to scleroderma target tissues.8 Thereafter, we investigated the presence of PV-B19 infection in cutaneous biopsies, as well as in skin fibroblasts and keratinocyte cultures. PV-B19 infection was demonstrated in the skin and/or bone marrow biopsies in 76% of patients with SSc. More interestingly, comparable levels of viral DNA were found in all passages of skin fibroblast cultures (from 3/3 to 6/6) using a semiquantitative polymerase chain reaction (PCR). Recently, we investigated the presence of parvoviral infection, tumour necrosis factor (TNF)- expression and C5b-9 deposition within cutaneous structures in skin biopsies from patients with SSc by means of solution-phase PCR, reverse transcriptase in situ PCR, and immunohistochemical and immunofluorescence studies. In particular, the presence of both PV-B19 DNA and TNF- mRNA was demonstrated in endothelia, fibroblasts, mast cells and perivascular inflammatory cells, along with C5b-9 deposits within the cutaneous vasculature