Anti-β₂-glycoprotein I IgG antibodies from 1-year-old healthy children born to mothers with systemic autoimmune diseases preferentially target domain 4/5: might it be the reason for their 'innocent' profile?
BACKGROUND
Anti-β₂-glycoprotein-I (anti-β₂GPI) were demonstrated to be pathogenic in the antiphospholipid syndrome (APS). However, they can be detected in patients with no features of APS, especially those affected by systemic autoimmune diseases (SAD), and so in healthy children. It has been suggested that anti-β₂GPI against domain 1 (D1) associate with thrombosis, while those recognising domain 4/5 (D4/5) are present in non-thrombotic conditions.


OBJECTIVE
To evaluate the fine specificity of anti-β₂GPI in adults and infants.


METHODS
Three groups were examined-group A: 57 1-year-old healthy children born to mothers with SAD; group B: 33 children with atopic dermatitis; group C: 64 patients with APS.


METHODS
were selected based on positive anti-β₂GPI IgG results. Serum samples were tested for anti-β₂GPI IgG D1 and D4/5 using research ELISAs containing recombinant β₂GPI domain antigens.


RESULTS
Children (A and B) displayed preferential IgG reactivity for D4/5, whereas patients with APS were mainly positive for D1. No thrombotic events were recorded in groups A and B.


CONCLUSIONS
The specificity for D4/5 suggests that anti-β₂GPI IgG production in children born to mothers with SAD is a process neither linked to systemic autoimmunity nor related to the maternal autoantibody status. This unusual fine specificity might, at least partially, account for the 'innocent' profile of such antibodies.
Rheumatology and Clinical Immunology,Spedali Civili, Piazzale Spedali Civili, Brescia, Italy.
Laura
L
Andreoli
Cecilia
C
Nalli
Mario
M
Motta
Gary L
GL
Norman
Zakera
Z
Shums
Susan
S
Encabo
Walter L
WL
Binder
Monica
M
Nuzzo
Micol
M
Frassi
Andrea
A
Lojacono
Tadej
T
Avcin
Pier-Luigi
PL
Meroni
Angela
A
Tincani
D000328:Adult; D000918:Antibody Specificity; D016736:Antiphospholipid Syndrome / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology*; D003876:Dermatitis, Atopic / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000276:immunology*; D007223:Infant; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology*; D011297:Prenatal Exposure Delayed Effects; D053482:beta 2-Glycoprotein I / Q000276:immunology*
D007074:Immunoglobulin G; D053482:beta 2-Glycoprotein I