Autoantibodies against calpastatin in sera from patients with systemic sclerosis.
OBJECTIVE
To determine the prevalence and clinical correlation of anti-calpastatin antibodies in patients with systemic sclerosis (SSc).


METHODS
Serum samples from patients with limited cutaneous SSc (lSSc; n=36), diffuse cutaneous SSc (dSSc; n=27), and healthy control subjects (n=29) were examined by an ELISA using human recombinant calpastatin as antigens.


RESULTS
IgG anti-calpastatin antibodies were positive in 15 (24%) of 63 patients with SSc, which was similar to the frequency of IgM anti-calpastatin antibody positivity (14/63, 22%). The presence of anticentromere antibodies was associated with the presence of IgG and/or IgM anti-calpastatin antibodies. The patients with SSc positive for IgG anti-calpastatin antibodies had significantly higher erythrocyte sedimentation rates (ESR) compared with those negative for IgG anti-calpastatin antibodies. Furthermore, the levels of IgG anti-calpastatin antibodies correlated positively with the levels of ESR. The patients with dSSc positive for IgM anti-calpastatin antibodies had significantly higher frequency of inflammatory joint and muscle involvement compared with those negative for IgM anti-calpastatin antibodies. Four (80%) of 5 patients with dSSc with both joint and muscle involvement produced IgM anti-calpastatin antibodies.


CONCLUSIONS
The presence of anti-calpastatin antibodies may be a clue to mechanisms of the inflammatory change occurring in SSc. Furthermore, the presence of anti-calpastatin antibodies could be a novel and useful serologic tool for recognizing patients with dSSc with inflammatory joint and muscle involvement.
Sato
S
S
Department of Dermatology, Kanazawa University School of Medicine, Ishikawa, Japan.
Hasegawa
M
M
Nagaoka
T
T
Takamatsu
Y
Y
Yazawa
N
N
Ihn
H
H
Kikuchi
K
K
Takehara
K
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000276:immunology; D000918:Antibody Specificity / Q000502:physiology; D001323:Autoantibodies / Q000032:analysis*; D001799:Blood Sedimentation; D002135:Calcium-Binding Proteins / Q000276:immunology*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012594:Scleroderma, Localized / Q000097:blood / Q000276:immunology / Q000503:physiopathology; D012595:Scleroderma, Systemic / Q000097:blood / Q000276:immunology* / Q000503:physiopathology
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D002135:Calcium-Binding Proteins; D007074:Immunoglobulin G; C033668:calpastatin