Systemic Lupus Erythematosus (S. L. E) is an auto- immune disease with unknown etiology. There are variety of auto- antibodies against cytoplesmic, nuclear and membranous antigens if S. L. E.
In this study several diagnostic tests of S. L. E. such as ANA, L. E. cell, RIA anti- ds DNA antibodies (Farr) and C. L. tests are used and compared in respect of sensitivity, specificity and efficiency in 52 S. L. E. 30 healthy control and 22 rheumatological patients.
Sera and the results are as follow.
Test |
Efficiency |
spacificity |
sensitivity |
AIA (Farr)
C. L.
ANA
LE cell |
91.33%
86.5%
78.8%
73.3% |
94.2%
96%
88.4%
* |
88.5
77%
71.1%
72.7% |
Quality correlation for each pair of tests are.
Test |
LEcell |
ANA |
C. L. |
RIA
C. L.
ANA |
80%
86.7%
73.3% |
75.9%
78.8%
- |
91.4%
-
- |
Regarding to the data RIA is the most efficient and sensitive test for S. L. E. while C. L. is the most specific and 2nd efficient test in this regard. Quality correlation for RIA, C. L. is 91.4%. Due to expensive instrument, highcost reagents and radioactive hazardous in RIA, there- for the C. L. is more Practical and effectivetest. In this study the purity of the subut- rate in RIA Kit For anti- dsDNA is determined by 125Iss DNA in 30 normal sera, and crossreactive antibodies are assessed by immunoabsorbtionassay using immunosorbant mBSA- ssDNA. ANA, C. L. and RIA (Farr) Tests are performed before and after absorption and the following results have been obtained.
1- Anti- ssDNA antibodies has no effect on anti- dsDNA Titration, C. L. tests, with noapparent effete on ANA.
2- The titer of the antibodies which crossreact with ssDNA and dsDNA are higher than antibodies which react only with ssDNA in S. L. E. patients.
3- Anti- ssDNA antibodies with hightiter exist in normal sera but they have no apparet effect on C. L, RIA or ANA tests.
Antibody classes in 52 S. L. E patients are determined and the results were as follow.
IgG= 75%, IgM= 25%, IgA= 43, IgG & IgM= 21%, IgG & IgM & IgA= 2% and there were no correlation between the different organ involvement and the class of antibody.