BACKGROUND & AIMS: Patients with systemic sclerosis (SSc) have impairments in
gastrointestinal smooth muscle function. The disorder has been associated with circulating
antibodies to cholinergic muscarinic the type-3 receptor (M3-R). We investigated whether it
is possible to neutralize these antibodies with pooled human IgGs (pooledhIgG). METHODS:
We studied the effects of IgGs purified from patients with SSc (SScIgGs) on cholinergic nerve
stimulation in rat colon tissues. We also examined the effects of SScIgGs on M3-R activation …

METHODS: We studied the effects of IgGs purified from patients with SSc (SScIgGs) on
cholinergic nerve stimulation in rat colon tissues. We also examined the effects of SScIgGs
on M (3)-R activation by bethanechol (BeCh), M (3)-R occupancy, and receptor binding
using immunofluorescence, immunoblot, and enzyme-linked immunosorbent analyses of
human internal anal sphincter (IAS) smooth muscle cells, before and after administration of
pooledhIgG. Functional displacement of M (3)-R occupancy by the SScIgGs was compared …