Statistics The individual patient or proband was defined as statistical unit. Data are shown as median with interquartile range and are presented as pg/ml (IL-1β, IL-6, IP-10) or as ng/ml (IL-8). Medians were compared between PLS patients and healthy volunteers using the non parametric Mann Whitney U test. Statistical analysis was performed using a computer program (Systat for Windows version 10.0, Systat Inc., Evanston, IL, USA).