Versican V0 and V1 mRNA levels in systemic sclerosis and control monocytes. Quantitative PCR analysis. Relative mRNA levels were calculated as a ratio of the level of the gene of interest to that of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Each bar in the graph denotes the mean. Differences between the groups were analyzed by Mann-Whitney U test. SSc, systemic sclerosis.