Autoantibodies in Connective Tissue Disease



Autoantibodies in Connective Tissue Disease

|Antibody |Associated Disease |Interpretation |Indication to order |Testing Technique |

|DS DNA = nDNA |-High level (>2-3 std dev, 1:320) confirms |-+ in only 50-80% of SLE |-Question of SLE |-indirect IF: uses crithidiae mitochondria which only|

| |clinical dx of SLE |-assoc with renal dz in SLE | |has dsDNA (so + or – only) |

| |-Low level in RA, Hashimoto, Graves, Waldenstrom, |- high value = specific for SLE | |- elisa: uses calf thymus, increased sensitivity, |

| |MCTD, SSc, AI liver dx, SS | | |gives a value |

|SS DNA |-Low diagnostic value |- + in normal people |- Rarely |- elisa: check by anti-DNA ab that is further |

| |-Increased in childhood linear morphea |- want > 3 std dev to be significant | |extracted to SSDNA from calf thymus |

| |-+ in many CTDs | | | |

|Histones |- Drug induced SLE (90%+) |- cannot exclude idiopathic SLE if + |- if suspect drug induced SLE |-IF: uses animal substrate like liver |

| |- SLE (30%+) | | |- elisa: uses commercial histone complement fixation |

|Anti- RO, SSA |-SS |- correlates with photosensitivity in|-w/u for photo-sensitivity |-Radial imunodiffusion: high spec, low sens (must |

| |-SLE |SCLE |-suspicion of neonatal LE, SS |contain lg amt to be +, so + = high diagnostic value)|

| |-SCLE (70-90%) |- incidence varies with testing |-suspicion of SCLE or SLE with |-Elisa: low spec, high sens (+ = low diagnostic value|

| |- Increased with vasculitis |technique |negative ANA |unless 2-3 std dev, but gives quantitative value) |

| |- Drug induced SCLE* | | | |

|Anti-LA, SSB |-same as RO, but incidence 50% less |-90% of pts with +LA have +RO |-same as RO |-same as RO |

|U1RNP |-MCTD (100% by definition) |-is to exclusion of other abs in MCTD|-attempting to confirm MCTD or SLE |-same as RO |

| |-SLE (30%) |-majority have SLE b/c SLE > MCTD | | |

| |-Rarely neonatal LE, SS | | | |

|Anti-SM |-SLE (very specific/diagnostic) |-confirms SLE |-attempting to confirm SLE |-same as RO |

| |-Only 15-40% + in SLE |-+ SM = + U1RNP | | |

| | |-+U1RNP not = + SM | | |

|SCL 70 |-SSc (incidence 10-20%) |-marker for worse dz (compared to |-to distinguish bad SSc from less bad| |

|(aka anti-topo- | |just CREST) | | |

|isomerase) | |-specific for SSc | | |

|Anti-centromere |CREST (50-90% positive) |- only 2% SSc have positve |Suspect CREST | |

|JO-1 |-Dermatomyositis, polymyositis |-associated with pulmonary sxs in SLE| | |

|(aka anti-histidyl-|-SLE | | | |

|tRNA synthase) | | | | |

nDNA, native DNA; SLE, systemic lupus erythematosus; RA, rheumatoid arthritis; MCTD, mixed connective tissue disease; SSc, systemic sclerosis (scleroderma); AI, autoimmune; SS, sjogren’s syndrome; IF, immunofluorescence;

*drugs assoc = hydrochlorothiazide, ACE inhibitors, Ca channel blockers, interferons, statins (Archives of Dermatology Jan 2003)

taken mainly from JAAD Nov 2000, CME

ANA Patterns and their Antigens and Disease Associations

|ANA |Predominant antigen |Disease |

|Peripheral |nDNA |SLE |

|Homogenous |nDNA, histones |SLE |

|Nucleolar |Nucleolar RNA |SSC, SLE |

|Centromere |Kinetochore |CREST |

|Speckled |Various ribonucleic proteins |SLE, SSc, SS |

Positive ANA in a healthy population Conditions other than CTDs with positive ANA

Titer Prevalence Elderly persons

1:40 32% Pregnancy

1:80 13% Relatives of patients with CTD

1:160 5% Other autoimmune disease (autoimmune thyroiditis, pimary biliary cirrhosis)

1:320 3% Chronic infections

Neoplasms

Medications (procainamide, hydralazine)

Normal healthy individual

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download