CNTNAP2 and viral encephalitis: In addition, Guan et al. (21) found 12.9% of 4,106 encephalitis patients to be positive for anti-NMDAR antibody, 12.8% for anti-LGI1 antibody, 5.6% for anti-GABABR antibody, 1.3% for anti-CASPR2 antibody, and 0.6% for anti-AMPA receptor antibody.