Relationship between the in vivo localization and the immunoblotting pattern of anti-basement membrane zone antibodies in patients with bullous pemphigoid

Abstract

Objective: To compare the localization of anti-basement membrane zone (BMZ) antibodies bound in vivo with the antigenic specificities of circulating anti-BMZ antibodies in patients with bullous pemphigoid (BP).

Design: Comparison of the results of an examination of the skin specimens of the patients using direct immunoelectron microscopy and direct immunofluorescence on 1-mol/L sodium chloride-split skin with the results of an analysis of the corresponding serum samples using the immunoblot technique.

Setting: Immunodermatology department in a teaching hospital.

Patients: Thirty-six patients with typical BP and circulating anti-BMZ antibodies.

Results: Serum samples from 22 patients with BP indicated only BP antigen 1 in the results of immunoblot analysis. Using direct immunofluorescence, an analysis of the peribullous skin samples obtained from these 22 patients showed deposits of IgG exclusively located along the epidermal side of sodium chloride-split skin; the results of direct immunoelectron microscopic examination showed deposits of IgG located on the intracellular portion of hemidesmosomes in 18 (82%) of these 22 specimens, whereas 4 biopsy specimens had linear IgG deposits located both intracellularly and extracellularly along the keratinocyte plasma membrane. The results of immunoblot analysis of the serum samples from 5 patients with BP indicated BP antigen 2 alone; the results of direct immunoelectron microscopic examination of peribullous skin samples from these 5 patients showed linear intracellular and extracellular deposits along the keratinocyte membrane, corresponding to an epidermal fluorescence labeling pattern of peribullous sodium chloride-split skin in 2 patients and a combined (dermal and epidermal) pattern in 3 patients.

Conclusion: The 2 different patterns of reactivity of anti-BMZ antibody deposits bound in vivo closely corresponded to the antigenic specificities indicated in the corresponding serum samples of the patients. These results are in accordance with those previously obtained in vitro and argue for identical binding profiles of circulating antibodies that are bound in vivo in BP.