Intravenous Immunoglobulins Lower Inflammatory Gene Expression in Skin Biopsies of Chronic Inflammatory Demyelinating Polyradiculoneuropathy Patients

according to CIDP Disease Activity Status (CDAS) [4, 6] . Twelve healthy volunteers were used as controls (‘Ctrl’ group). Skin punch biopsies were performed 10 cm above the external malleoli and snap frozen in liquid nitrogen. RNA extraction, gene expression profiling, and MetaCore ® data analysis were performed according to the methods described previously [4] with the following filters: fold expression change >1.15, p < 0.05, Y chromosome linked genes and duplicate removal. Data analysis was made according to a 3 set comparison (C), where C1 stands for ‘IVIG vs. Ctrl’, C2 for ‘IVIG vs. NoIVIG’, and C3 for ‘NoIVIG vs. Ctrl’. This study was approved by the local Ethics Committee (protocol 235/10). We first analyzed the total number of differentially regulated genes between the 3 groups. Results showed 223 differentially regulated genes between patients treated with IVIG and the control group (C1; fig. 1 a). In contrast, numbers of differentially regulated genes were much higher when comparing NoIVIG patients to IVIG and the control group respectively: 1117 genes were differentially regulated between Dear Sir, Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common form of chronic autoimmune neuropathy [1] . The underlying immune-mediated mechanisms have not yet been fully elucidated [2], but gene expression analyses identified inflammatory molecular markers that are upregulated in skin nerve biopsies [3, 4] . Intravenous immunoglobulins (IVIG) are a first-line therapy for CIDP [5] . In order to gain insight in the anti-inflammatory effects of IVIG, 2 subgroups of patients treated with either IVIG or other immunosuppressive agents were selected from a previous gene expression profiling study [4] . The selected subgroups were further studied using a transcriptional microarray analysis in skin punch biopsies. Four patients (‘IVIG’ group) were treated with Privigen ® (2 g/kg administered over 5 days) 2–6 months before skin biopsy was performed. Three patients (‘NoIVIG’ group) received other treatments: prednisone (30 mg/day), azathioprine (2 mg/kg/ day) or tacrolimus (2 mg/day), respectively. All 7 patients had stable active disease Received: March 18, 2016 Accepted: May 17, 2016 Published online: June 11, 2016