The autoantibody profile associated with known
autoimmune diseases in
patients with COVID-19 or multisystem inflammatory
syndrome in
children (MIS-C) remains poorly defined. Here we show that
adults with COVID-19 had a moderate
prevalence of
autoantibodies against the
lung antigen KCNRG, and SLE-associated Smith
autoantigen.
Children with COVID-19 rarely had
autoantibodies; one of 59
children had GAD65
autoantibodies associated with acute
insulin-dependent diabetes. While
autoantibodies associated with SLE/
Sjogrens syndrome (Ro52, Ro60, and La) and/or autoimmune
gastritis (gastric
ATPase) were detected in 74% (40/54) of MIS-C
patients, further
analysis of these
patients and of
children with
Kawasaki disease (KD), showed that the
administration of
intravenous immunoglobulin (
IVIG) was largely responsible for
detection of these
autoantibodies in both groups of
patients.
Monitoring in vivo decay of the
autoantibodies in MIS-C
children showed that the
IVIG-derived Ro52, Ro60, and La
autoantibodies declined to undetectable levels by 45-60 days, but gastric
ATPase autoantibodies declined more slowly requiring >100 days until undetectable. Together these findings demonstrate that
administration of high-
dose IVIG is responsible for the
detection of several
autoantibodies in MIS-C and KD. Further studies are needed to investigate autoantibody
production in MIS-C
patients, independently from
IVIG administration.