Extractable Nuclear Antigens (ENA) Antibodies, Serum

The presence of antinuclear antibodies is a hallmark of rheumatic autoimmune diseases. Autoantibodies reacting with nuclear proteins like Smith antigen (Sm), topoisomerase I (Scl-70) Centromere proteins, amino-acyltRNA synthetase, SS-A or SS-B and RNP are characteristic for SLE, systemic sclerosis (SSc), CREST syndrome (calcinosis, Raynaud’s phenomenon, oesophageal dysmotility, sclerodactyly, and telangiectasia syndrome), polymyositis, Sjögren’s syndrome and mixed connective tissue disease (ctd) respectively.

Common indications for anti-ENA testing are to establish a diagnosis of CTDs in patients with suggestive clinical features; to exclude CTDs in patients with few or uncertain clinical findings; to sub-classify patients known to have CTDs into prognostic groups; and to monitor disease activity. ENA antibody testing is recommended after a positive ANA test result. With the exception of antibodies to cytoplasmic antigens such as Jo-1, it is rare to have a positive anti-ENA antibody test in the absence of a positive ANA test. See Appendix

1 ml Serum Stability: 14 Days at 2-8 °C

RNP/sm: Negative SS-A native: Negative Sm: Negative Ro-52: Negative SS-B: Negative Scl-70: Negative PM-Scl: Negative Jo-1: Negative Centromere B: Negative PCNA: Negative ds DNA: Negative Nucleosomes: Negative Histones: Negative Rib, P-Protein: Negative AMA-M2: Negative