As expected, clinical and histological scores of arthritis, evaluated each week from day 0 to day 55 after induction of CIA, were correlated (P < 0.0001, r = 0.74, Spearman correlation test). More importantly, angiogenesis increased as a function of the disease course. A correlation was observed between joint vascularization and clinical scores of arthritis (P < 0.0001, r = 0.61). A correlation was also shown between vascularization and histological scores (P = 0.0006, r = 0.51). The overexpression of VEGF induced by gene transfer was followed by an aggravation of arthritis as compared with the AAV-lacZ control group (P < 0.0001, analysis of variance test). Histological and quantification of angiogenesis are in progress in this experiment.