LAG3 and Parkinson disease: As a result, the mean value of sLAG3 in CSF was significantly lower in PD patients compared to HC subjects (PD, 51.56 ± 15.05 pg/ml; control 88.49 ± 62.96 pg/ml, p < 0.0001), but no difference of serum sLAG3 was found in the two groups (PD, 433.2 ± 25.67, N = 78; control 485.0 ± 29.67 pg/ml, N = 61; p = 0.19, Additional file 2).