F2R and myalgic encephalomeyelitis/chronic fatigue syndrome: In contrast, for F2R/PAR-1- and CHRM1-Ab, the regression coefficient was negative in PCS/non-ME/CFS, indicating that lower levels of these AABs were associated with the non-ME/CFS phenotype in regards to PCS/ME/CFS, as well as for CHRM2 in HC (Supplementary Table 3).