Small nuclear ribonucleoproteins
Small nuclear ribonucleoproteins are highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm, and pre-rRNA processing in the nucleolus Antibodies to these proteins may be clinically significant in a number of rheumatological diseases.
"Systemic lupus erythematosus is characterized by production of autoantibodies to RNA or DNA–protein complexes such as small nuclear ribonucleoproteins (snRNPs). A role of Epstein–Barr virus in the pathogenesis has been suggested. Similar to Epstein–Barr virus, cytomegalovirus (CMV) infects the majority of individuals at a young age and establishes latency with a potential for reactivation...CMV [may have a role] in regulation of autoantibodies to snRNPs" 
- Anonymous (2021), Small nuclear ribonucleoproteins (English). Medical Subject Headings. U.S. National Library of Medicine.
- Claudia Azucena Palafox Sánchez et al. (2009), "Reduced IgG anti-small nuclear ribonucleoprotein autoantibody production in systemic lupus erythematosus patients with positive IgM anti-cytomegalovirus antibodies", Arthritis Research & Therapy 11: R27, DOI:10.1186/ar2621
- Robert W Hoffman and Eric L Greidinger (7 August 2008), "Mixed Connective-Tissue Disease: Overview", eMedicine Specialties > Rheumatology > Systemic Rheumatic Disease