Serum levels of the high-mobility group box 1 protein (HMGB1) in children with type 1 diabetes mellitus: case-control study

Introduction
The involvement of the high-mobility group box 1 protein (HMGB1) in various auto­immune and inflammatory diseases has been documented; however, the role of this proinflammatory molecule in children with diabetes type 1 (T1DM) has not been addressed. The aim of this case-control study is to compare the serum level of HMGB1 in children with newly diagnosed T1DM (group 1) and a control group composed of healthy children.

Material and methods
This case-control study included 136 children: group 1 (n = 96) and a control group (n = 40). Measurements were taken from serum for the following: HMGB1, white blood cell count, C-reactive protein, glucose, haemoglobin A_1C, and β-cell autoantibodies (GADA-65, IA-2, ICA). HMGB1 was determined using enzyme-linked immunosorbent assay on a Labsystems iEMS Reader MF analyser (Labsystems Diagnostics Oy, Helsinki, Finland).

Results
The level (median and interquartile range) of HMGB1 was statistically higher (p < 0.001) in children with T1DM: 8.7 (5.0-9.8) µg/l, in comparison with the control group: 1.0 (0.6-1.4) µg/l. No correlation was found between HMGB1 and HbA1c in group 1, or between HMGB1 and BMI. A statistically higher percentage of positive children for autoantibodies were present in group 1 compared to the control group (p ≤ 0.001). HMGB1 serum levels were also tested and the presence of autoantibodies, and none of those antibodies correlated with the level of HMGB1.

Conclusions
The higher level of HMGB1 in children with T1DM, compared to the control group, indicates that this proinflammatory molecule is a good candidate marker of inflammation in children with T1DM.