Human parvovirus B19 (B19V) infection in systemic sclerosis patients.

BACKGROUND: Our previous reports suggested a possible association between parvovirus B19 (B19V) infection and systemic sclerosis (SSc), based on higher prevalence of B19V DNA in SSc patients in respect to controls. METHODS: In the present study, to further evaluate the differences in the pattern of B19 infection in SSc, skin biopsies and bone marrow samples from patients and controls were analysed for B19V DNA detection, genotyping and viral expression. RESULTS: B19V DNA was detected in skin biopsies from 39/49 SSc patients and from 20/28 controls. Bone marrow showed positive in 17/29 SSc patients, 5/21 haematological patients and 0/10 healthy controls. Genotype 1 was more frequent in skin and bone marrow from patients than from controls. Simultaneous persistence of 2 genotypes was detected in SSc skin and bone marrow samples, never in controls. Viral mRNA for capsid protein was detected in the skin of genotype 1-positive patients and not in control skins. CONCLUSION: The results outline some differences in the rate of persistence of B19V DNA, in the simultaneous persistence of 2 genotypes and in the pattern of viral expression among SSc patients and controls.

Tissue persistence of parvovirus B19 genotypes in asymptomatic persons.

Parvovirus B19 (B19V) can persist in immunocompetent symptomatic and non-symptomatic individuals, as demonstrated by the finding of viral DNA in different tissues, in absence of viremia and of anti-B19V IgM. The spread and the nature of this phenomenon have not been clearly determined. In order to investigate the frequency of persistence and the tissue distribution of the three genotypes of B19V, the viral load of the persistent virus and its expression in the affected tissues, 139 tissue samples and 102 sera from 139 asymptomatic individuals have been analyzed by consensus PCRs and genotype specific PCRs for B19V detection and genotyping. Viral load was measured by real time PCR and viral mRNAs were detected by RT-PCR. Altogether, 51% individuals carried B19V DNA, more frequently in solid tissues (65%) than in bone marrow (20%). Genotype 1 was found in 28% tissue samples, genotype 2 in 68% and genotype 3 in 3% only. Viral load ranged from less then 10 copies to 7 x 10(4) copies per 10(6) cells, with the exception of two samples of myocardium with about 10(6) copies per 10(6) cells. mRNA of capsid proteins was present in two bone marrow samples only. In conclusion, in asymptomatic individuals B19V persistence is more common in solid tissues than in bone marrow, and genotype 2 persists more frequently than genotype 1. The results suggest that the virus persists without replicating, at sub-immunogenic levels.