ICAP
AC-17 - Cytoplasmic fibrillar segmental
Previous Nomenclature None
Description Enhanced decoration of short segments, periodic dense bodies, along the stress fibers. e.g. anti-alpha-actinin, anti-vinculin.
Antigen Association alpha-actinin, vinculin
Clinical Relevance
First level information
About Clinical Relevance

Found very infrequently in a routine serology diagnostic setting

Antigens recognized include α-actinin and vinculin; specific immunoassays for these autoantibodies are currently not commercially available

First level information references
Second level information

Autoantibodies to α-actinin:

In SLE and lupus nephritis cross-reactive anti-α-actinin and anti-dsDNA autoantibodies have been reported as pathogenic (21)

Reported as part of the anti-cell membrane antibody spectrum that characterize patients with lupus nephritis; also reported as a biomarker to differentiate patients with lupus nephritis from those without renal involvement (22, 23)

Reported with relatively high prevalence (~40%) in patients with AIH type 1 and associated with more severe disease, clinical and histological disease activity, predictor of therapeutic response, and double positivity with anti-ssDNA antibodies (24-26)

Autoantibodies to vinculin:

Reported in 2 of 31 patients with chronic inflammatory demyelinating neuropathy (27)

 

Notes: Most reports describe autoantibodies directly binding to specific antigens (i.e. antigen-specific immunoassays) and none actually shows correlations with the AC-17 pattern as such; specific immunoassays for these autoantibodies are currently not commercially available.

Second level information references
21.
Zhao Z, Weinstein E, Tuzova M, et al. Cross-reactivity of human lupus anti-DNA antibodies with alpha-actinin and nephritogenic potential. Arthritis Rheum 2005;52:522-30.
22.
Seret G, Canas F, Pougnet-Di Costanzo L, et al. Anti-alpha-actinin antibodies are part of the anti-cell membrane antibody spectrum that characterize patients with lupus nephritis. J Autoimmun 2015;61:54-61.
23.
Zhang WH, Pan HF, Zhao XF, et al. Anti-alpha-actinin antibodies in relation to new-onset systemic lupus erythematosus and lupus nephritis. Mol Biol Rep 2010;37:1341-5.
24.
Gueguen P, Dalekos G, Nousbaum JB, et al. Double reactivity against actin and alpha-actinin defines a severe form of autoimmune hepatitis type 1. J Clin Immunol 2006;26:495-505.
25.
Renaudineau Y, Dalekos GN, Gueguen P, et al. Anti-alpha-actinin antibodies cross-react with anti-ssDNA antibodies in active autoimmune hepatitis. Clin Rev Allergy Immunol 2008);34:321-5.
26.
Zachou K, Oikonomou K, Renaudineau Y, et al. Anti-alpha actinin antibodies as new predictors of response to treatment in autoimmune hepatitis type 1. Aliment Pharmacol Ther 2012;35:116-25.
27.
Beppu M, Sawai S, Satoh M, et al. Autoantibodies against vinculin in patients with chronic inflammatory demyelinating polyneuropathy. J Neuroimmunol 2015;287:9-15.
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Online since 19 May 2015