SLE is which type of hypersensitivity reaction:March 2005

Ans. C: Type III hypersensitivityType III hypersensitivity response (Immune-complex mediated response) Examples are:Some form of glomerulonephritisSerum sicknessAhus reactionSLEAntinuclear antibody (ANA) testing and anti-extractable nuclear antigen (anti-EN A) form the mainstay of serologic testing for SLE.Several techniques are used to detect ANAs. Clinically the most widely used method is indirect immunofluorescence. The pattern of fluorescence suggests the type of antibody present in the patient's serum.ANA screening yields positive results in many connective tissue disorders and other autoimmune diseases, and may occur in normal individuals.Subtypes of antinuclear antibodies include anti-Smith and anti-double stranded DNA (dsDNA) antibodies (which are linked to SLE) and anti-histone antibodies (which are linked to drug-induced lupus).Anti-dsDNA antibodies are highly specific for SLE; they are present in 70% of cases, whereas they appear in only 0.5% of people without SLE.The anti-dsDNA antibody titers also tend to reflect disease activity, although not in all cases.