The levels of transforming growth factor-β1 are increased in the serum of patients with psoriasis and correlate with disease severity

The serum transforming growth factor-β1 (TGF-β1), the soluble intercellular adhesion molecule (sICAM-1), the soluble E-selectin (sE-selectin), the soluble L-selectin (sL-selectin) and the interleukin-1 receptor antagonist (IL-1Ra) levels were determined in 15 samples of psoriatic serum using commercially available ELISA kits. The median serum TGF-β1 levels were significantly increased as compared to the 21 healthy subjects and a significant correlation with the PASI scores was observed, suggesting an involvement of this cytokine in the pathogenic mechanisms of plaque-type psoriasis. Despite 4 weeks of effective therapy and a subsequent drop in the PASI scores, no significant TGF-β1 modifications were observed in the treated patients, suggesting a persistence of the raised levels of this molecule in the blood. This has been previously shown for other molecules, suggesting a time dissociation between TGF-β1 metabolism and recovery. Significant correlations were found with the serum TGF-β1, sICAM-1, sE-selectin, sL-selectin and IL-1Ra levels, whose interrelationships with TGF-β1 have been previously reported in the literature. This indirectly suggests that the amounts of serum TGF-β1, although altered, are biologically coordinated and may be active, exerting functions known to be TGF-β1-dependent such as monocyte stimulation, neo-angiogenesis and fibroblast activation.