P-31 Presence, viral load and sequence analysis of JC virus in the urine of Italian healthy subjects

The human polyomavirus JC virus (JCV) infects a large part of population worldwide and after the primary infection, usually occurring during childhood, remains latent in the kidney. Since up to 50% of normal adult has been shown to excrete JCV in the urine we performed this study to evaluate the frequency of viruria in a group of 17 healthy subjects followed for 8 weeks. The study was set to evaluate the presence of JCV viruria, JCV viral load, to characterize by molecular JCV strains detected, and the possible relation with the presence of squamous cells of the urinary sediment. A total of 333 urine samples were collected and the highly conserved large T (LT) antigen coding region of JCV genome was searched by nested PCR, and then in the positive samples the VP1 and TCR region were amplified and eventually subjected to nucleotide sequence analysis. JCV DNA was detected in 47% of subjects, with significant differences between positive samples in females (33.3%) and males (62.5%) (p < 0.001). JCV genotype 1 was the most frequently detected (62.5%) followed by JCV type 2 (25%) and type 4 (12.5%). All the strains amplified from the urine samples showed an archetypal organization of the TCR. In all samples the microbial load was not significant according with an asymptomatic viral excretion. In order to define a possible relation between JCV excretion and cellular presence we performed a quantitative assay by Real Time PCR. Every single subject showed an independent and continuous excretion pathway, indicating that the JC virus is spread by healthy people as a consequence of an active viral reactivation, and with different viral load on the basis of the individual physiological status. The lack of any correlation between JCV DNA detection and the presence of squamous cells in the sediment indicate that viruria is regulated by JCV life cycle and is not a consequence of the damage of renal tissues.