[Survival prognosis in pemphigoid. A cohort analysis of 78 patients]

Bullous pemphigoid (BP) is the most frequent autoimmune bullous skin disease and usually affects elderly patients. Despite some conflicting data, vital prognosis is poor in BP, of which mortality rate after one year of treatment varies between 10 and 40 p. 100. To date, the factors influencing this prognosis remain to be determined.

A cohort of 78 consecutive patients with BP (mean age: 80 +- 4 years) has been prospectively selected on a six-year period (1987-1992) in Limoges. The diagnosis of BP was made on clinical criteria (using a standardized questionnaire), direct immunofluorescence (IF) findings (linear deposits of IgG and/or C3 along the basement membrane zone) and confirmed by direct immunoelectron microscopy and/or Western immunoblotting on epidermal extracts.

The follow-up analysis (mean duration of follow-up: year of treatment (22 p. 100 in the first three months) with an actuarial survival curve inclined to be horizontal by the end of this first year of treatment. Therefore, we have studied the clinical or immunologic factors susceptible to influence the vital prognosis of BP according to this main criterion: death (or survival) at the end of the first year of treatment. None of the following factors has been found to be significantly linked to the vital prognosis in BP: age, sex, extent of skin lesions at presentation, presence of mucosal lesions, blood eosinophilia, presence of circulating basement membrane zone autoantibodies by indirect IF. The clinical factors of bad prognosis were an altered general condition and a history of coronaropathy. The presence of circulating autoantibodies against BP180 antigen (but not the one of autoantibodies against BP230) as detected by immunoblotting on epidermal extracts was found to be significantly more frequent (50 vs 22 percent) in BP patients who died within the first year of treatment (p < 0.02).

Although modestly discriminating, the presence of circulating autoantibodies against BP180 represents the first vital prognosis factor demonstrated in BP. This result confirms the growing pathophysiologic importance of the anti-BP180 autoantibodies of which the pathogenic role has been recently formally demonstrated in BP using an animal model.