In CSF, CHIT1, YKL-40 and MCP-1 showed a weak discriminatory performance between ALS and ALS mimics (area under the curve: 0.79, p<0.0001; 0.72, p=0.001; 0.75, p=0.001, respectively).
Chitinase proteins distinguished ALS from healthy controls (area under the curve (AUC): CHIT1 0.92; CHI3L1 0.80; CHI3L2 0.90), mimics (AUC: CHIT1 0.84; CHI3L1 0.73; CHI3L2 0.88) and, to a lesser extent, PLS (AUC: CHIT 0.73; CHI3L1 0.51; CHI3L2 0.82) but did not outperform pNFH.
We have employed a very simple and affordable laboratory test to measure blood Chit and lysosomal enzymes activity which could be easily included in the screening of ALS patients recruited in clinical trials.