SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus
Odile Billaut-Mulot, … , André Capron, George M. Bahr
Odile Billaut-Mulot, … , André Capron, George M. Bahr
Published September 15, 2001
Citation Information: J Clin Invest. 2001;108(6):861-869. https://doi.org/10.1172/JCI13469.
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Article

SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus

Abstract

Certain autoimmune disorders, including Sjögren syndrome (SS) and systemic lupus erythematosus (SLE), are characterized by autoantibodies against the Ro/SSA and La/SSB cellular antigens. Although the implication of these autoantibodies in disease pathogenesis is still unclear, it is believed that the aberrant responses against autoantigens may extend to other proteins that are not yet well defined. In an attempt to analyze the regulated gene expression in lymphocytes by an HIV-suppressive immunomodulator, we have identified and cloned a novel gene encoding a 56-kDa protein, named SS-56, which is structurally related to the 52-kDa Ro/SSA antigen. The new protein showed primarily perinuclear cytoplasmic localization, and recombinant SS-56 was found to react in ELISA with sera from most patients with SS or SLE. Western blot analysis confirmed the autoantigenic nature of native SS-56 in extracts from HeLa cells. Interestingly, the incidence of antibodies to SS-56 was associated with visceral complications in SLE, and roughly half of the 17 SS or SLE patients with no detectable antibodies to SSA and SSB antigens presented measurable antibodies against recombinant SS-56. Thus, SS-56 represents a new member of the SS family of autoantigens and could become an additional and important diagnostic marker for SS and SLE.

Authors

Odile Billaut-Mulot, Cécile Cocude, Vincent Kolesnitchenko, Marie-José Truong, Edward K.L. Chan, Eric Hachula, Xavier de la Tribonnière, André Capron, George M. Bahr

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Levels of autoAb’s against rSSA-60, rSS-56, rSSA-52, and rSSB-48 in sera...
Levels of autoAb’s against rSSA-60, rSS-56, rSSA-52, and rSSB-48 in sera from selected SS and SLE patients. Twenty-five patients (13 SS and 12 SLE), reported as negative for anti-SSA and anti-SSB antibodies by the immunodiffusion technique, were analyzed for autoAb levels to the four recombinant proteins by ELISA. Absorbance values reflect the activity at serum dilution of 1:900. Horizontal line represents the cut-off point of positivity calculated as the mean + 2 SD of the values obtained from healthy controls, against each of the tested antigen.