CCL2 and type 1 diabetes mellitus: CCL2 is constitutively secreted by non-stimulated monocytes and its concentration was 1,416 pg/ml (range 418–6,019) in controls and 1,198 pg/ml (range 208–3,227) in monocytes from T1D patients (Figure 2B) thus being similar in unstimulated monocytes isolated from controls or T1D patients.