Long-COVID (LC) is characterized by diverse and persistent symptoms,
potentially mirroring different molecular pathways. Recent data might
offer that one of them is mediated by functional autoantibodies (fAAb)
targeting G protein-coupled receptors (GPCR). Thus, the aim of this
study was to investigate the clinical phenotype of patients with LC in
relation to their GPCR-fAAb seropositivity. The present study recruited
194 patients with LC and profiled them based on self-reported symptoms.
GPCR-fAAb seropositivity was identified by using a cardiomyocyte
bioassay, testing the presence and functionality of the AAbs. Logistic
regression, clustering, and decision tree analyses were applied to
examine associations between GPCR-fAAb profiles and self-reported
symptoms considering age and gender. The most prevalent GPCR-fAAbs in
patients with LC were fAAB targeting the β2 adrenergic receptor
(β2-fAAb, 92.8%), the muscarinergic M2 receptor (M2-fAAb, 87.1%), the
Angiotensin II type 1 receptor (AT1-fAAb, 85.6%), and angiotensin (1–7)
Mas receptor (MAS-fAAb, 85.6%). β2-fAAb showed a significant relation
with dizziness, lack of concentration, and POTS, while Endothelin Type A
receptor functional autoantibody (ET-A-fAAb) was significantly related
to deterioration of pre-existing neurological disorders. Statistical
analysis indicated a strong positive correlation between M2- and
β2-fAAb; as in addition, an association of β2-fAAb and gender was
observed to one of the major clinical symptoms (fatigue/PEM), a critical
impact of GPCR-fAAb on LC-pathogenesis can be assumed. Summing up, the
present data show that specific GPCR-fAAb are associated with distinct
clinical phenotypes. Especially, the combination of M2- and β2-fAAb
seemed to be essential for the LC-phenotype with a combination of
fatigue/PEM and lack of concentration as major clinical symptoms.