Primary Sjögren's syndrome and deficiency of ICA69.
BACKGROUND
Sjögren's syndrome is a common (about 1% of the population) autoimmune disease of salivary and lacrimal glands. Its cause and pathogenesis are poorly understood, and treatments are mostly for symptoms of the disease. ICA69 is a self-antigen expressed in brain, pancreas, salivary, and lacrimal glands. NOD-strain mice are an animal model of spontaneous Sjögren's syndrome. We aimed to assess the role of ICA69 in autoimmunity against Sjögren's syndrome.


METHODS
We inactivated the genomic ICA69 locus, generated NOD congenic mice that were deficient in ICA69, and assessed development of Sjögren's syndrome. ICA69 autoimmunity was investigated in controls and in patients with primary Sjögren's syndrome or systemic lupus erythematosus, and in various NOD mice, some of which were given an ICA69-directed prototype peptide vaccine.


RESULTS
Disruption of the ICA69 locus prevented lacrimal gland disease and greatly reduced salivary gland disease in NOD mice. In healthy NOD mice, ICA69-specific T cells accumulated in lymph nodes that drain salivary tissue. T-cell and B-cell autoreactivity against ICA69 was much the same in patients with primary Sjögren's syndrome, but not in those with systemic lupus erythematosus or in healthy controls. Immunotherapy with a high-affinity mimicry peptide targeting ICA69-specific T-cells reduced established Sjögren's syndrome in wild-type NOD mice in the long term.


CONCLUSIONS
ICA69 is a new autoantigen in primary Sjögren's syndrome that has an important role in progression of disease and could be of diagnostic value. Immunotherapy of primary Sjögren's syndrome is promising, since autoimmunity in NOD mice with Sjögren's syndrome seems to be uniquely susceptible to such treatment even late in disease.
Winer
Shawn
S
Hospital for Sick Children, Research Institute, ON, Toronto, Canada.
Astsaturov
Igor
I
Cheung
Roy
R
Tsui
Hubert
H
Song
Aihua
A
Gaedigk
Roger
R
Winer
Daniel
D
Sampson
Anastasia
A
McKerlie
Colin
C
Bookman
Arthur
A
Dosch
H-Michael
HM
D000328:Adult; D000367:Age Factors; D000818:Animals; D001324:Autoantigens / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D016022:Case-Control Studies; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000235:genetics / Q000276:immunology / Q000628:therapy; D051379:Mice; D020297:Mice, Congenic; D016688:Mice, Inbred NOD; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000235:genetics / Q000276:immunology* / Q000628:therapy; D013363:Submandibular Gland / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology
D001324:Autoantigens; C087054:ICA1 protein, human; C490184:Ica1 protein, mouse