CCL2 and isolated hemihyperplasia: As compared to such previous data, our study is carried out on a larger sample size, reports a serum reduction of MCP-1, rather than a mRNA tissue reduction, and evidences the reduction at an earlier stage (mean age of the regressing IH in the present study is 34 months, vs 40 months mean age in the Greenberger study), supporting the conclusion that MCP-1 may represent a relevant early non invasive marker of regression.