Detection of pemphigus antigens by immunoblot analysis and indirect immunofluorescence using cultured keratinocytes

Kim, Soo Chan; Won, Jin Hyoung; Ahn, Sung Ku

Abstract

BACKGROUND: Pemphigus are chronic autoimmune blistering disorcers characterized by acantholysis. In addition to pemphigus vulgaris(PV), the major clinical variarts are pemphigus foliaceus(PF), paraneoplastic pemphigus(PNP) and drug-induced pemphigus(DP). Detection of pemphigus antigen is important for differential diagnosis as well as research work. Most investigators have identified pemphigus antigens by means of immunoprecipitation using metabolically radiolabeled cultured keratinocytes. However, immunorepitation is generally more expensive, hazardous and time-consuming than immunoblotting. Therefore, establishment of the immunoblotting as a standard technique for the detection of the pemphig us antigens is desirable.
OBJECTIVE
To characterized pemphigus antigens by an immunobloting analysis of human epidermal extract and by indirect itnmunofluroscence study using human of cultured keratinocytes as a substraie. METHOD: We performed imrnunoblotting analysis af sera from patieiits with PV, PF, PNP and DP with human epidermal extract as a source of antigen. Indirect immunof uorescence study was also performed using human keratinocytes cultured in high or low calcium media for detection of pemphigus antigens.
RESULTS
In an immunoblotting analysis, all(9/9) PV sera showed secific reactivities with a 130-KD protein and all(5/5) FF sera showed reactivities with a 150-KK protein, which is most likely desmoglein 1. Furthermore, one of nine PV serum also reacted with a 150-KD protein, which seems to be the identical antigen detected in PF. All PNP(3/3) sera showed reactivities with two protein bands, 210KD and 190KD. In our indirect imrnunofluorescence study using culltured human keratinocytes as a substrate, when keratinocytes were grown in low calcium media, no pimphigus antigens could be detected. However, when grown in high calciurn media, pemphigus vulga ris and paraneoplastic pernphigus antigens were present t the cell-cell contact areas with a puncta;e pattern, whereas pemphigus foliaceus antigen was not, presint in keratinocytes even when cultured in high calcium media.
CONCLUSION
Our results suggests (1) immunoblotting analysis is a reliable technique for defining pemphigus antigen and could be a valuable tool for the differentiation of PV, PF and PNP and(2) PF antigen rnay not be expresseden cultured keratinocytes.