Serum levels of monocyte chemoattractant protein 4 (CCL13) levels were determined in 80, 20, 29, 29 and 50 subjects with systemic sclerosis (SSc), systemic lupus erythematosus (SLE), dermatomyositis (DM), atopic dermatitis (AD) and normal controls, respectively. CCL13 levels were highest in the SSc group, followed by DM, SLE, AD and control subjects, respectively (P < 0.001 for all comparisons of SSc group vs. others). Serum CCL13 levels did not differ in patients with limited or diffuse cutaneous SSc and levels were generally unchanged over a mean follow-up of 3.8 years. CCL13 may be a promising marker for SSc in future therapeutic trials (Yanaba, K. et al. Br J Dermatol 2010,162(2): 332).