Background Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are autoimmune bullous skin diseases mediated by autoantibodies against adhesion molecules of the skin. Previous studies have identified autoreactive T cells in patients with BP and PV, which may be critical in providing B‐cell help for autoantibody production.

Objectives To evaluate the frequency of autoreactive T‐helper (Th) 1 and Th2 cells in patients with BP (n = 7) or PV (n = 1) and in healthy controls (n = 11).

Methods In an enzyme‐linked immunospot (ELISPOT) assay, microtitre plates were coated with antihuman interleukin (IL)‐5 IgG or antihuman interferon (IFN)‐γ IgG prior to culturing human peripheral blood lymphocytes (PBL) with BP180 or desmoglein (Dsg) 3 proteins for 7 days. Cytokine‐producing autoreactive T cells were visualized as spot‐forming units.

Results One BP patient with extensive blisters had 5·1 ± 1·5 (mean ± SD) BP180‐reactive Th1 cells and 2·9 ± 1·5 Th2 cells per 10⁵ PBL. In contrast, PBL from six BP patients in remission or on immunosuppressive therapy did not form IFN‐γ‐ or IL‐5‐producing spots per ≤ 5 × 10⁵ PBL. The patient with oral PV had 4·7 ± 2·4 Th1 cells and 3·0 ± 0·4 Th2 cells per 10⁵ PBL and a vigorous PBL response to Dsg3. In addition, three of 10 controls had BP180‐reactive Th1 (2·7–13·8 per 10⁵ PBL) and Th2 (0·3–1·8 per 10⁵ PBL) cells and one control had 9·0 ± 0·7 Th1 cells and 1·1 ± 0·8 Th2 cells per 10⁵ PBL, with reactivity to Dsg3. ELISPOT reactivity correlated with ³H‐thymidine incorporation in six of seven patients and controls with autoreactive T‐cell responses.

Conclusions The ELISPOT assay seems to be promising for the quantitative and qualitative analysis of autoreactive T‐cell responses in BP and PV.