Which of the following antibodies correlates with disease activity for S.L.E -

Ans. is 'b' i.e., Anti-ds DNA antibody Autoantibodies in Systemic Lupus Erythematosus (SLE)AntibodyPrevalence%Antigen RecognizedClinical Utilityo Antinuclear antibodies98Multiple nuclearBest screening test; repeated negative tests make SLE unlikelyo Anti-dsDNA70DNA (double-stranded)High titers are SLE-specific and in some patients correlate with disease activity, nephritis, vasculitiso Anti-Sm25Protein complexed to 6 species of nuclear U1 RNASpecific for SLE; no definite clinical correlations; most patients also have anti-RNP; more common in blacks and Asians than whiteso Anti-RNP40Protein complexed to U1 RNAyNot specific for SLE; high titers associated with syndromes that have overlap features of several rheumatic syndromes including SLE; more common in blacks than whiteso Anti-Ro (SS-A)30Protein complexed to hY RNA, primarily 60 kDa and 52 kDaNot specific for SLE; associated with sicca syndrome, predisposes to subacute cutaneous lupus, and to neonatal lupus with congenital heart block; associated with decreased risk for nephritiso Anti-La (SS-B)1047-kDa protein complexed to hY RNAUsually associated with anti-Ro; associated with decreased risk for nephritiso Anti hi stone70Histones associated with DNA (in nucleo- some, chromatin)More frequent in durg-induced lupus than in SLEo Antiphospholipid50Phospholipids, (3, glycoprotein 1 cofactor. prothrombinThree tests available - ELISAs for cardiolipin and (LG 1, sensitive prothrombin time (DRVVT); predisposes to clotting, fetal loss, thrombocytopeniao Antiervthrocyte60Eiythrocyte membraneMeasured as direct Coombs' test; a small proportion develops overt hemolysiso Antiplatelet30Surface and altered cytoplasmic antigens on plateletsAssociated with thrombocytopenia but sensitivity and specificity are not good; this is not a useful clinical testo Antineuronal (includes anti-glutamate receptor)60Neuronal and lympho-In some series a positive test in CSF correlates with cyte surface antigens active CNS lupuso Antiribosomal P20Protein in ribosomesIn some series a positive test in serum correlates with depression or psychosis due to CNS lupus