ENA and ANA Additonal Flashcards
why are ENA called extractable?
the antigens can be removed from the cell nuceli using saline.
6 main proteins antibodies detected agaisnt
Ro, La, Sm, RNP, Scl-70 and Jo-1
SLE common antibodies and their target
Anti-Sm, anti-SSA/Ro, SSB-La.
Smith protein is used in processing of small nuclear ribonucloproteins. Anti-Sm are highyl specific for SLE and are not seen in other AID diseases.
Mixed Connective Tissue antibodies
Anti-RNP(Ribonucleoprotein)
These antibodies target a group of proteins associated with RNA. There are two main types; anti-U1RNP and anti-U2RNP antibodies. These are asssociated with MCTD and sometimes SLE.
Sjogrens sydrome antibodies
Anti-SSA-Ro, Anti-SSB-La
These target the Ro and La antigens respectively and are common findings for SLE abd Sjogrens. SSA is assocaited with photosensitivity and neonatal lupus when present in pregnant women.
Scleroderma antibodies
Scl-70 and anti-centromere
Scl-70 are connected to scleroderma which affects the skin and the internal organs.
Polymysitis and dermatomyositis
anti-Jo-1
These target the histidyl-tRNA synthease and are connected ti poly and dermamyositis which are inflammatory muscle disorders.
Diagnostic use of the ENA profile
- Disease identification: ENA are highly connected to the presence of specific autoimmune conditions and aids in the identification/isolation of specific diseases.
- Disease differentiation
AID can express vague symptoms which can make it challenging to differeniate different conditions and therefore ENA profile resutls can help to determine which AID it is likely to be, aids in exclusion of theories. - Early identification
ENA profile testing can detect antibodies presence in specific AIDs before symptoms have onset allowing for early treatment/prevention.
4.Monitor disease progression
Changes in Ab levels overtime help provide insight into disease progression and treatment effectivness.
ANA vs ENA
The ANA tests for the presence or absence of autoantibodies, while the ENA panel evaluates which proteins in the cell nucleus the autoantibodies recognize. The ENA panel helps diagnosis, distinguish between, and monitor the progression of autoimmune diseases
SO ANA is screening test (indirect immunofluroscnce) and ENA is specific (ELISA style)
why are Hep 2000 cells used
Large nuclei and therefore have a large number of dividing cells, displaying mitoitic figures, which allows for detection of antigens which are expressed at different stages of cell cycle. This cell can also be tranfected with other antigens (SSA)
has the most nuclear and cytoplasmic antigens
what conjugate does ENA and ANA use
ANA - FITC (Fluorescein isothiocyanate)
ENA - alkaline phosphatase labelled IgG
ANA titre meaning
The titre is the level to which a patient’s sample can be diluted and still produce recognizable staining pattern (fluroscence) is known as the ANA “titer.”
The ANA titer is a measure of the amount of ANA in the blood; the higher the titer, the more autoantibodies are present in the sample. As it takes more dilutions to reach the end point of no fluroscence.
High level of ANA in sample: High titre (more clinically significant, 1:160 or more)
Low levels of ANA in sample: Low titre (less clinically significant, 1:80 or below)
source of false negative in ANA
Fixation with ethanol/methanol causes the removal of SSA and therefore fixed with acetone.
ANA titre meaning
HIGH titre (1:160+): Clinically significant and high concentration of antibodies in sample and therefore a high titre result (last well to show a visible fluroscence). Needs more dilution to create end point
LOW titre (1:80): less clinically significant but may still be relevant, less ab present in sample, less dilution needed to reach endpoint
Titre 1:40: not usually clinically significant as this is very borderline + and therefore generally doesn’t provide much clinical value.
