Keywords: CLL, chronic lymphocytic leukemia; DSG, desmoglein; ELISA, enzyme-linked immunosorbent assay; EP, envoplakin; IIF, indirect immunofluorescence; PNP, paraneoplastic pemphigus; PP, periplakin; SJS, Stevens-Johnson syndrome; Stevens-Johnson syndrome; TEN, toxic epidermal necrolysis; paraneoplastic pemphigus; toxic epidermal necrolysis.