SLE

Clinical information

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease belonging to the group of connective tissue diseases. The classification criteria of the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) revised in 2019 contain 7 clinical and 3 immunological categories with the individual parameters weighted using a point system. A case is classified as SLE if the entry criterion of a positive ANA test is fulfilled and the total score is at least 10.

Antibodies against double-stranded DNA (dsDNA) are the main focus of serological SLE diagnostics. These antibodies can be found in 60% to 90% of patients, depending on the activity of the disease. In rare cases, anti-dsDNA antibodies are also found in patients with other autoimmune diseases (e.g. autoimmune hepatitis) or infections and in clinically healthy persons. 85% of people in the latter group develop SLE within 5 years of initial detection of anti-dsDNA. However, SLE cannot be excluded if anti-dsDNA antibodies are not detected.

Antibodies against nucleosomes are also an exclusive marker of SLE, provided that they are determined using a test system with a target antigen that is free of histone H1, Scl-70 and other non-histone proteins. Anti-Sm antibodies are also highly specific markers but occur a lot less frequently. Anti-Sm and anti-dsDNA antibodies each have a high weighting of 6 points in the classification criteria.

Diagnostics

Various test methods are available for the routine detection of antibodies against dsDNA: enzyme immunotests such as ELISA or EUROLINE and the Crithidia luciliae immunofluorescence test (CLIFT). The various test systems differ, sometimes greatly, regarding their sensitivity and specificity. The conventional CLIFT, for example, shows a particularly high disease specificity, while the IIFT Crithidia luciliae sensitive was developed with a focus on high sensitivity. 

Thanks to the use of highly purified nucleosomes as linking substance, the performance data of the Anti-dsDNA-NcX ELISA are significantly higher than those of the conventional Anti-dsDNA ELISA. Because of their strong adhesive ability, even a very low concentration of these nucleosomes is suited to coupling isolated dsDNA to the surface of a microplate well. False positive reactions due to conventional linking substances such as poly-L lysine and protamine sulphate are avoided.

In a clinical comparative study of 564 patients with rheumatic diseases (of these 207 with SLE), the Anti-dsDNA-NcX ELISA yielded an 8% higher sensitivity than the Anti-dsDNA RIA (Biesen et al., Arthritis Res Ther (2011) 13:R26). Nevertheless, different test methods identify different SLE subgroups, so different test systems should be combined to increase the serological detection rate.

Techniques

Method
Parameter
Substrate
Species
IIFT
cell nuclei
(ANA global test)
HEp-2 cells
liver
(2 BIOCHIPs per field)
human
monkey
IIFT
cell nuclei (ANA) EUROPattern
cell nuclei (ANA)
HEp-2 cells
liver
(2 BIOCHIPs per field)
human
monkey
IIFT
cell nuclei
(ANA global test)
HEp-20-10 cells
liver
(2 BIOCHIPs per field)
human
monkey
IIFT
cell nuclei (ANA) EUROPattern
cell nuclei (ANA)
HEp-20-10 cells
liver
(2 BIOCHIPs per field)
human
monkey
IIFT
EUROPLUS ANA Mosaic 10A
cell nuclei (ANA)
SS-A + SS-B
2 BIOCHIPs per field:
HEp-20-10 cells
SS-A+SS-B BIOCHIPs

human
IIFT
cell nuclei (ANA) EUROPattern
mitochondria (AMA)
HEp-20-10 cells
kidney
(2 BIOCHIPs per field)
human
rat
IIFT
EUROPLUS ANA Mosaic 22A
cell nuclei (ANA)
cell nuclei (ANA)
nRNP/Sm + Sm + SS-A
SS-B + Scl-70 + Jo-1
4 BIOCHIPs per field:
HEp-20-10 cells
liver
nRNP/Sm+Sm+SS-A BIOCHIPs
SS-B+Scl-70+Jo-1 BIOCHIPs

human
monkey
IIFT
cell nuclei (ANA)
HEp-2 cells
human
IIFT
cell nuclei (ANA)
EUROPattern
HEp-2 cells
human
IIFT
cell nuclei (ANA)
HEp-20-10 cells
human
IIFT
cell nuclei (ANA)
EUROPattern
HEp-20-10 cells
human
ELISA
histones
antigen-coated
microplate wells
IIFT
antibodies against cell nuclei
(ANA control), homogeneous pattern
ChLIA
IDS dsDNA IgG

antigenic coated magnetic particles
ELISA
double-stranded DNA
(dsDNA)
antigen-coated
microplate wells
IIFT
dsDNA
EUROPattern
flagellates
Crithidia luciliae
IIFT
dsDNA
flagellates
Crithidia luciliae
IIFT
antibodies against dsDNA
(dsDNA ab control)
ELISA
dsDNA-NcX
antigen-coated
microplate wells
IIFT
dsDNA (sensitive)
EUROPattern
flagellates
Crithidia luciliae
IIFT
dsDNA (sensitive)
flagellates
Crithidia luciliae
ELISA
nucleosomes
antigen-coated
microplate wells
ChLIA
IDS ANA Control Set
3 x 1.5mL Control 1/2
EUROLINE
Anti-ENA ProfilePlus 1
(nRNP/Sm, Sm, SS-A, Ro-52, SS-B,
Scl-70, Jo-1 separately)
EUROLINE
EUROLINE
ANA Profile 23
(nucleosomes, dsDNA, histones, SS-A, Ro-52,
SS-B, nRNP/Sm, Sm, Mi-2 alpha, Mi-2 beta, Ku, CENP A,
CENP B, Sp100, PML, Scl-70, PM-Scl100, PM-Scl75,
RP11, RP155, gp210, PCNA, DFS70 separately)
EUROLINE
EUROLINE
ANA Profile 3
(nRNP/Sm, Sm, SS-A, Ro-52, SS-B, Scl-70, PM-Scl,
Jo-1, CENP B, PCNA, dsDNA, nucleosomes,
histones, ribosomal P-proteins, AMA M2 separately)
EUROLINE
EUROLINE
ANA Profile 3 plus DFS70
(nRNP/Sm, Sm, SS-A, Ro-52, SS-B, Scl-70, PM-Scl,
Jo-1, CENP B, PCNA, dsDNA, nucleosomes, histones,
ribosomal P-proteins, AMA M2, DFS70 separately)
EUROLINE
EUROLINE
ANA Profile et Mi-2 et Ku
(Mi-2, Ku, nRNP/Sm, Sm, SS-A, Ro-52, SS-B, Scl-70,
PM-Scl, Jo-1, CENP B, PCNA, dsDNA, nucleosomes,
histones, ribosomal P-proteins, AMA M2 separately)
EUROLINE
EUROLINE
dsDNA, nucleosomes, histones, DFS70
EUROLINE
EUROLINE
ANA Profile et Mi-2, Ku, DFS70
(Mi-2, Ku, nRNP/Sm, Sm, SS-A, Ro-52, SS-B, Scl-70,
PM-Scl100, Jo-1, CENP B, PCNA, dsDNA,
nucleosomes, histones, ribosomal P-proteins,
AMA M2, DFS70 separately)
EUROLINE
EUROLINE
Cytoplasm profile
(AMA M2, M2-3E, ribosomal P-proteins, Jo-1
SRP, PL-7, PL-12, EJ, OJ, Ro-52 separately)
EUROLINE
EUROLINE
ANA Profile 5
(nRNP/Sm, Sm, RNP70, RNPA, RNPC, SS-A,
Ro-52, SS-B, Scl-70, PM-Scl, Jo-1, CENP B,
PCNA, dsDNA, nucleosomes, histones,
ribosomal P-proteins, AMA M2 separately)
EUROLINE
EUROLINE
ANA Profile 1
(nRNP/Sm, Sm, SS-A, Ro-52, SS-B, Scl-70,
Jo-1, CENP B, dsDNA, nucleosomes, histones,
ribosomal P-proteins separately)
EUROLINE
ChLIA
IDS Sm

antigenic coated magnetic particles
ELISA
Sm
antigen-coated
microplate wells
ELISA
ribosomal P-proteins
antigen-coated
microplate wells
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