Background: Bullous pemphigoid is an autoimmune bullous disease with circulating anti-basement membrane zone antibodies, and it commonly affects elderly individuals; however, the reasons for the late onset of the disease are unclear.
Design: The anti-basement membrane zone antibodies in serum samples from normal elderly subjects were compared with those in serum samples from normal young subjects.
Participants: Serum samples from 32 elderly and 28 young normal individuals and 10 patients with bullous pemphigoid were used.
Interventions: Indirect immunofluorescence against guinea pig esophagus or human salt-split epidermis and immunoblotting against human and guinea pig epidermis were performed.
Results: Serum samples from young individuals were devoid of anti-basement membrane zone antibodies against guinea pig esophagus and human salt-split epidermis. Among 32 serum samples from elderly patients, 6 cases (19%) were positive for anti-basement membrane zone antibody for guinea pig esophagus, and in those the titers were 10 in 3 cases and 40, 80, and 320 in the others. One case was positive against human split epidermis at a titer of 10. An immunoblotting analysis showed that the antigenicity of the 230-kd and 180-kd bullous pemphigoid antigen from guinea pig epidermal extract was similar to that of human epidermal extract; however, the molecular weight was slightly different. The 4 cases of elderly serum that recognized guinea pig esophagus basement membrane zone showed positivity with the 230-kd peptide in the guinea pig epidermal extract; however, they were negative with the human epidermal extracts. Direct immunofluorescence observation of these cases showed that deposition of IgG or C3 was not present in cryostat sections from flexor arm surfaces.
Conclusions: The serum samples from elderly subjects possessed a relatively high incidence of anti-basement membrane zone antibodies detectable with guinea pig esophagus as substrate. This observation of a specific immune defect in elderly individuals might explain why they are more susceptible to developing bullous pemphigoid.