We thank Drs Velthuis and de Jong for their comments on our article.1 In brief, we do not believe our case represents a variant of bullous pemphigoid (BP). Our patient with Waldenström macroglobulinemia had a pruritic papular eruption and immunopathologic findings, suggesting that his IgM-κ paraprotein had specificity for the epidermal basement membrane zone. Our patient's serum sample contained an IgM-κ antiepidermal basement membrane zone antibody that bound both sides of 1 mol/L of sodium chloride-split human skin, showing greatest reactivity against the dermal side (floor) of this substrate—a finding unusual in BP. Moreover, we were unable to immunoprecipitate the 230- or 180-kd BP antigens with our patient's serum sample using a previously described technique that identified antibody reactivity against these antigens in patients with generalized, localized, or variant forms of BP.2 Finally, our patient's eruption was responsive to oral psoralen in combination with UV-A radiation (ie, PUVA),
Cobb CMW, Domloge-Hultsch N, Yancy KB. The Significance of Linear IgM Deposits in the Basement Membrane Zone-Reply. Arch Dermatol. 1992;128(12):1653. doi:10.1001/archderm.1992.04530010089022
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