Abstract
Procedures for IgG depletion in visceral leishmaniasis (VL) and
schistosomiasis sera using Sepharose-protein G beads also deplete IgE.
In this study, the presence of IgG anti-IgE autoantibodies in sera from
patients with VL (n = 10), and hepatic-intestinal schistosomiasis (n =
10) and from healthy individuals (n = 10) was investigated. A sandwich
ELISA using goat IgG anti-human IgE to capture serum IgE and goat
anti-human IgG peroxidase conjugate to demonstrate the binding of IgG
to the IgE captured was performed. VL sera had higher titers (p <
0.05) of IgG anti-IgE autoantibodies (OD = 2.01 ± 0.43) than sera
from healthy individuals (OD = 1.35 ± 0.16) or persons infected
with Schistosoma mansoni (OD = 1.34 ± 0.18). The immunoblotting
carried out with eluates from Sepharose-protein G beads used to deplete
IgG from these sera and goat anti-human IgE peroxidase conjugate,
showed a similar pattern of bands, predominating the 75 kDa e-heavy
chain and also polypeptides resulting from physiological enzymatic
digestion of IgE. A frequent additional band immediately above 75 kDa
was observed only in VL sera.