Anti-Epidermal Basement Membrane Zone Antibody (Anti-EBMZ)

The epidermal BMZ shows small, regularly spaced electron dense structures which are the hemidesmosomes. Thin, extracellular, electron-dense lines, parallel to the plasma membrane, subjacent to the outer plaque are visible in one third of HDs and are termed sub-basal dense plates (SBDPs). The case of a patient with Waldenström macroglobulinemia and IgM-κ paraprotein who had development of an eruption of pruritic papules and demonstrated the following unusual immunopathologic findings: (1) deposits of IgM-κ in the epidermal basement membrane zone of lesional and nonlesional skin; (2) a circulating IgM-κ antiepidermal basement membrane zone antibody; and (3) binding of this circulating IgM-κ antiepidermal basement membrane zone antibody to both sides of 1 mol/L sodium chloride split skin. The cutaneous eruption cleared completely with oral psoralen with long-wave UV radiation in the A range (PUVA) therapy.