Anti-basement membrane zone antibodies in elderly patients with pruritic disorders and diabetes mellitus.

Anti-basement membrane zone (anti-BMZ) antibodies are detectable in a low percentage of elderly subjects without clinical signs of bullous pemphigoid (BP). BP may initially mimic other pruritic dermatoses and may be more common in patients with diabetes mellitus (DM), since DM is frequently associated with pruritic disorders. The aim of the present study was to analyse a possible association of BP and DM and to detect subclinical BP among elderly patients with pruritic dermatoses. Ninety elderly patients (78.6 +/- 4.7 years) treated for dermatologic conditions were divided into four groups: I. DM+/pruritus+, II. DM-/pruritus+, III. DM+/pruritus-, and IV. DM-/pruritus-. Patients' sera were tested by indirect immunofluorescence (IIF) on monkey oesophagus; positive or dubious results were further evaluated by ELISA with human recombinant BP180 and BP230 proteins and purified laminin 5. Positive results were found in 1 of 21 (4.8%) patients in group I, 6/31 (19.3%) patients in group II, 1/18 (5.5%) patients in group III, 3/20 (15%) patients in group IV. In the whole cohort positive anti-BMZ antibodies of linear or basal cell cytoplasmic and membrane pattern were found in 11 cases (12.2%). ELISA was positive in 11/29 (37.9%) tested sera for at least one antigen (BP180, BP230 and laminin 5 ELISA was positive in 7, 5, and 2 sera, respectively). Positive IIF corresponded with positive ELISA in 6/11 (54.5%) cases (ELISA with BP180, BP230, laminin 5 was positive in 5, 3, and 1 serum, respectively). Thus, by IIF, a significant portion of elderly patients had anti-BMZ antibodies and these findings were confirmed by ELISA. There was no statistically significant difference in the presence of anti-BMZ antibodies among the groups I-IV. Thus, the association of anti-BMZ antibodies with age overrules the potential association with DM and/or pruritus.