Lymphocytic chemotactic ability was assessed using a modified Boyden chamber assay.<h4>Results</h4>VLA4 expression was significantly downregulated on CD3+ T cells, CD56+ NK cells, and CD3+/CD56+ NK-T cells from PD patients; further, an increase of the soluble VLA4 ligand VCAM1 in patient plasma was noted. Here, NCAM1 is linked to Parkinson disease.