Session Information
Title: Systemic Sclerosis, Fibrosing Syndromes and Raynaud's - Pathogenesis, Animal Models and Genetics II
Session Type: Abstract Submissions (ACR)
Background/Purpose: Raynaud’s Phenomenon (RP) is frequently seen in autoimmune conditions, but an autoimmune basis for RP has not been established.
Methods: Sera derived from anti-RNP+ individuals were screened for antibodies associated with RP by immunoprecipitation, western blot, and ELISA. Autoantigen targets were then identified by mass spectrometry. Biological effects of antigen-specific monoclonal antibodies as well as human and murine antisera were assessed in in vitro endothelial cell culture and in vivo adoptive transfer experiments involving various wild type and knockout mice.
Results: Immunoprecipitation and mass spectrometric sequencing identified cytokeratin 10 (K10) as a putative antigen linked to RP in anti-RNP+ sera. Subsequent ELISA-based screening of 123 anti-RNP+ patients demonstrated that antibodies to K10 were strongly linked to the presence of RP (present in 92% of RP patients; Odds Ratio of RP in anti-K10+ patients = 4.6 (95% confidence interval 1.6-13.4). In vitro endothelial expression of K10 was confirmed at the mRNA and protein level by rtPCR and western blot, respectively. Fluorescence microscopy further demonstrated that anti-K10 antibodies bound to the surface of K10-expressing endothelial cells, with corresponding induction of endothelial cell apoptosis not observed with control antibodies. Endothelial cell K10 expression (but not other cytokeratins) was found to be dramatically upregulated by cold exposure in vitro. Consistent with these observations, in vivo passive transfer of anti-K10+ antisera or anti-K10 monoclonal antibodies to wild type recipient mice induced a high rate of ischemia and damage of thermoregulatory tissues (ears and tail) that was exacerbated by preconditioning with cold exposure. These effects were not observed in K10 knockout mice, which were resistant to tissue ischemia induced by either anti-K10 antisera or mAb.
Conclusion: Anti-K10 antibodies induce endothelial apoptosis, mediate a murine model of RP via their recognition of the K10 antigen, and are strongly linked with clinically evident RP in human anti-RNP autoimmunity. These findings suggest that RP may be driven by anti-K10 or other endothelial apoptosis-inducing antibodies, establishing the foundation for development of novel diagnostic and treatment modalities in this frequent complication of systemic autoimmune disease.
Disclosure:
D. P. Ascherman,
None;
Y. Zang,
None;
L. Martinez,
None;
J. Pignac-Kobinger,
None;
I. Fernandez,
None;
E. L. Greidinger,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/autoantibody-mediated-raynauds-phenomenon-animal-model-and-human-disease/