Anti-GM1 and anti-sulfatide antibodies in polyneuropathies. Threshold titers and accuracy.
OBJECTIVE
To determine threshold titers and diagnostic accuracy of anti-GM1 and anti-sulfatide antibodies (Ab) for autoimmune polyneuropathies (PN) in overall and for particular subtypes of them.


METHODS
In this study 84 PN patients, 120 epileptics and 93 healthy controls' sera were tested by enzyme-linked immunosorbent assay for autoAbs and results confirmed by thin-layer chromatography. Frequencies of positive patients at increasing cut-off were compared to determine threshold titers. Accuracy was determined by Receiver Operator Characteristic analysis.


RESULTS
A 1:2,000 titer for IgM anti-GM1 and a 1:4,000 titer for IgM anti-sulfatide Ab resulted to be threshold titers for autoimmune PN in overall. IgM anti-GM1 and anti-sulfatide Ab had low discriminating capacity between autoimmune PN and other PN, but good discriminating capacity between motor neuropathy (for anti-GM1 Ab) or PN in IgM-paraproteinemia or chronic painful sensory axonal PN (for anti-sulfatide Ab) and other PN.


CONCLUSIONS
Our results suggest that testing IgM anti-GM1 or anti-sulfatide Ab is useful only for diagnostic confirmation of specific subtypes of autoimmune PN.
Clinica Neurologica I, Dipartimento di Neuroscienze, Università di Torino, Italy.
G
G
Isoardo
B
B
Ferrero
P
P
Barbero
A
A
Cucci
A
A
Oggero
A
A
Pipieri
A
A
Ricci
E
E
Verdun
B
B
Bergamasco
L
L
Durelli
D000368:Aged; D000917:Antibody Formation; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D016537:Gangliosidosis, GM1 / Q000276:immunology*; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D011115:Polyneuropathies / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D012016:Reference Values; D012680:Sensitivity and Specificity; D013433:Sulfoglycosphingolipids
D007075:Immunoglobulin M; D013433:Sulfoglycosphingolipids