SYSTEMIC SCLEROSIS PROFILE - (S)

Test Code: SSP

Alternate Name(s):
Sclerosis
Systemic Sclerosis
Scleroderma

Test Indications: Systemic sclerosis (SSc), also called scleroderma, is a chronic autoimmune disorder characterized by fibrosis of the skin and various organs.  Initial triaging should include an ANA IFA pattern (centromere, nucleolar, and/or speckled patterns), clinical presentation, and/or ethnicity. Note: 5-10% of patients with SSc are ANA IFA negative
 

_SH Approval for Test Referral Immunology and Hematology F150-100-100

_SH Immunology Autoimmune Laboratory Requisition (R250-10-85)

Reference Intervals: Negative
 A negative result does not necessarily exclude autoimmune disease.  Positive results should not be interpreted in isolation and must be correlated with relevant clinical findings

Method of Analysis: The Line Blot Immunoassay provides qualitative in vitro determination of human autoantibodies of the immunoglobulin class IgG to the 13 different antigens Scl-70, CENP A, CENP B, RP11 and RP155 (RNA Polymerase III subunits), fibrillarin, NOR90, Th/To, PM-Scl100, PM-Scl75, Ku, PDGFR (platelet derived growth factor receptor) and Ro-52 in serum.  The test kit contains test strips coated with parallel lines of highly purified antigens. In the first reaction step, the immunoblot strips are incubated with diluted patient samples. In the case of positive samples, the specific IgG antibodies (also IgA and IgM) will bind to the corresponding antigenic site. To detect the bound antibodies, a second incubation is carried out using an enzyme-labelled anti-human IgG (enzyme conjugate) catalysing a colour reaction.

EUROLINE Systemic sclerosis (Nucleoli) profile (IgG) Test Instruction, DL_1532G_A_UK_C06.doc, Version 20/03/2018
 

Within 1 Week

Ordering restricted to Specialists or by Prior Approval

Interpretation & Assay Interferenes: 
Autoantibodies of immunoglobulin class IgG against the 13 most important and most relevant of the currently known SSc-specific antigens can be detected in serum. The determination of SSc-specific autoantibodies is an important element in the serological diagnosis of systemic sclerosis, including early diagnosis, activity of the disease, monitoring of the disease course, prognosis and differentiation from other collagenoses (e.g. SLE, polymyositis, Sharp syndrome and Sjögren’s syndrome).
 

SSc-specific autoantigens	Autoantibody prevalence
Scl-70 (DNA topoisomerase I)	Depending on activity, course & prognosis 40-78% in SSc (diffuse form) 5-15% in SSc (limited form)
CENP A and CENP B (centromere protein A and centromere protein B)	5-10% in SSc (diffuse form) 80-95% in SSc (limited form)
RNA Polymerase III	5-22% in SSc (diffuse form)
Fibrillarin (U3-RNP)	5-10% in SSc (diffuse form)
NOR90 (nucleolus-organizing region)	rarely (<5% in SSc)
Th/To (7-2-RNP/7-2-RNA protein complex)	rarely (<5% in SSc)
PM-Scl (antigen complex of 11-16 polypeptides, major antigens PM-Scl100 and PM-Scl75), incl. overlap syndrome	10-20% in SSc
Ku	rarely (<5% in SSc)
PDGFR (platelet derived growth factor receptor)	rarely (<5% in SSc)