Antibodies to carbonic anhydrase and IgG4 levels in idiopathic chronic pancreatitis: relevance for diagnosis of autoimmune pancreatitis.
BACKGROUND
Increased serum antibodies against carbonic anhydrase II (CA-II Ab) or IgG4 levels have been reported in cases of autoimmune chronic pancreatitis (ACP).


OBJECTIVE
To assess the relevance of serum CA-II Ab and IgG4 levels for the diagnosis of ACP in idiopathic CP (ICP) versus alcoholic CP and Sjogren's syndrome (SS).


METHODS
This was a multicentre study involving 227 subjects divided into four groups: ICP (n = 54), normal controls (n = 54, paired by age and sex with ICP patients), alcoholic CP (n = 86), and SS (n = 33).


METHODS
CA-II Ab was measured by ELISA and confirmed by western blotting. A score of easy clinical use with major clinical, morphological, and biochemical parameters for the diagnosis of ACP was applied.


RESULTS
The percentage of patients with increased serum CA-II Ab was higher in the ICP group (28%) than in controls (1.9%) and in patients with alcoholic CP (10.5%), but lower than in patients with SS (64%). The proportion with elevated IgG4 levels was higher in the ICP group (15%) compared with controls (1.9%) and SS (0%) but not significantly different from alcoholic CP (8%). Most ICP patients (7/8) with high IgG4 levels exhibited increased CA-II Ab and a compatible ACP score. A definitive diagnosis of ACP by histological analysis was associated with other autoimmune disorders, an increase in both serum IgG4 and CA-II Ab levels, and IgG4 positive plasma cells.


CONCLUSIONS
The increase in serum IgG4 levels was strongly associated with elevated CA-II Ab levels, manifestations compatible with ACP, and lymphoplasmacytic infiltration when surgical specimens were available.
Aparisi
L
L
Unit of Heptatology, University Clinic Hospital, Valencia, Spain. aparisi_lui@gva.es
Farre
A
A
Gomez-Cambronero
L
L
Martinez
J
J
De Las Heras
G
G
Corts
J
J
Navarro
S
S
Mora
J
J
Lopez-Hoyos
M
M
Sabater
L
L
Ferrandez
A
A
Bautista
D
D
Perez-Mateo
M
M
Mery
S
S
Sastre
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D024402:Carbonic Anhydrase II / Q000276:immunology*; D002908:Chronic Disease; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D019512:Pancreatitis, Alcoholic / Q000175:diagnosis / Q000276:immunology; D010950:Plasma Cells / Q000276:immunology; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D024402:Carbonic Anhydrase II