Immunofluorescence testing in the diagnosis of autoimmune blistering diseases: Overview of 10-year experience

Background: immunofluorescence testing is an important tool for diagnosing blistering diseases.objective: to characterize the immunofluorescence findings in patients diagnosed with autoimmune blistering skin diseases.methods: we retrospectively analyzed immunofluorescence results encompassing a 10-year period.results: 421 patients were included and divided into 2 groups: group 1- intraepidermal blistering diseases (n=277) and 2- subepidermal blistering diseases (n=144). for group 1,positive dif findings demonstrated: predominance of igg intercellular staining (ics) and c3 for pemphigus foliaceus-pf (94% and 73% respectively),pemphigus vulgaris-pv (91.5%-79.5%) and paraneoplastic pemphigus-pnp (66%-33%); ics iga in 100% of iga pemphigus cases,and igg deposits in the basement membrane zone (bmz) along with ics in one hailey-hailey patient. the iif findings revealed mean titers of 1:2.560 for pv and 1:1.280 for pf. for paraneoplastic pemphigus,iif was positive in 2 out of 3 cases with rat bladder substrate. in group 2,positive dif findings included multiple deposits at basement membrane zone for epidermolysis bullosa acquisita-eba (c3-89%,igg-79%,iga-47%,igm-21%) mucous membrane pemphigoid-mmp (c3,igg,iga,igm-80%) and bullous pemphigoid-bp (c3-91%,igg-39%,iga-11%,igm-6%),and iga at basement membrane zone for iga linear disease (99%) and dermatitis herpetiformis-dh (dermal papillae in 84.6%). for lichen planus pemphigoides,there was c3 (100%) and igg (50%) deposition at basement membrane zone. indirect immunofluorescence positive findings revealed basement membrane zone igg deposits in 46% of bp patients,50% for eba,15% for iga linear dermatosis and 50% for lpp. indirect immunofluorescence positive results were higher for bp and eba with salt-split skin substrate.conclusion: our results confirmed the importance of immunofluorescence assays in diagnosing autoimmune blistering diseases,and higher sensitivity for indirect immunofluorescence when salt-split skin technique is performed. © 2014 by anais brasileiros de dermatologia.