Is It Anti-RNP or Anti-Sm/RNP?

Antibodies against ribonucleoprotein (RNP) are an important serologic marker for mixed connective tissue disease (MCTD). RNP interacts with Smith (Sm) proteins to form the Sm/RNP complex. Antigens for detecting U1-RNP antibody may include purified extracts (Sm/RNP complex), recombinant proteins, synthetic peptides, or dominant epitopes of the three main proteins (RNPA, RNPC, and RNP68/RNP70) either independently or in various combinations.

 

Patients with systemic lupus erythematosus frequently have antibodies to both Sm and RNP, whereas patients with MCTD only have antibodies to RNP.  RNP antibodies can be detected using diverse types of solid-phase immunoassays. As a consequence of the variety of antigens and methods in use, considerable confusion exists regarding nomenclature, reporting and interpretation of anti-RNP testing.

 

In this webinar, we will review the various RNP antigens and methods for antibody detection, and use case studies to illustrate challenges associated with interpretation of results and approaches for improving the nomenclature for reporting RNP antibodies.

 

Learning Objectives