IgA and IgG autoantibodies against alpha-fodrin as markers for Sjögren's syndrome. Systemic lupus erythematosus.
OBJECTIVE
To determine the prevalence of IgA and IgG autoantibodies against alpha-fodrin in patients with primary and secondary Sjögren's syndrome (SS) and controls.


METHODS
An ELISA detecting IgA and IgG antibodies against alpha-fodrin was developed. We examined the prevalence of IgA and IgG antibodies against alpha-fodrin in patients with primary and secondary SS, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA) and blood donors.


RESULTS
IgA antibodies against alpha-fodrin were detected in 64% of patients with primary SS (n = 85), 47% of patients with secondary SS and SLE (n = 15), and 86% of patients with secondary SS and RA (n = 7). IgA autoantibodies against alpha-fodrin were detected in only one of 160 sera obtained from blood donors and in one of 50 and 2 of 12 sera obtained from SLE and RA patients without sicca syndrome, respectively. The prevalence of IgG antibodies against alpha-fodrin in SS was lower: they were detected in 55% of sera obtained from patients with primary SS, 40% of patients with secondary SS and SLE, and in 43% of patients with secondary SS and RA. Three of 160 sera from blood donors and one of 50 and 5 of 12 sera from SLE and RA patients without sicca syndrome, respectively, contained IgG antibodies against alpha-fodrin.


CONCLUSIONS
IgA rather than IgG antibodies against alpha-fodrin are specific for and frequently observed in primary and secondary SS and are useful markers for this autoimmune disorder.
Witte
T
T
Abteilung Klinische Immunologie, Medizinische Hochschule Hannover, Germany. witte.torsten@mh.hannover.de
Matthias
T
T
Arnett
F C
FC
Peter
H H
HH
Hartung
K
K
Sachse
C
C
Wigand
R
R
Braner
A
A
Kalden
J R
JR
Lakomek
H J
HJ
Schmidt
R E
RE
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis*; D015415:Biomarkers; D001782:Blood Donors; D002352:Carrier Proteins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis*; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology; D008297:Male; D008840:Microfilament Proteins / Q000276:immunology*; D008875:Middle Aged; D012859:Sjogren's Syndrome / Q000150:complications / Q000276:immunology*; D013049:Spectrin
D001323:Autoantibodies; D015415:Biomarkers; D002352:Carrier Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008840:Microfilament Proteins; D013049:Spectrin