Bullous Pemphigoid with Psoriasis Shows Distinct IL-17A Signature and Earlier Disease Onset
Background
Despite the recognized association between bullous pemphigoid (BP), a severe autoimmune blistering skin disease, and psoriasis (PsO), a chronic inflammatory skin condition, the specific clinical and immunological profiles of their co-occurrence remain poorly defined. Understanding these distinct characteristics, particularly the underlying inflammation patterns, is crucial for identifying potential therapeutic targets. Current treatments for BP often involve broad immunosuppression, which may not optimally address the specific inflammatory drivers in patients with comorbid psoriasis, highlighting a significant gap in tailored management strategies.
Study Design
Researchers conducted a retrospective cohort study to characterize the clinical and immunological features of 140 bullous pemphigoid patients without psoriasis (BP alone group) and 24 BP patients with comorbid psoriasis (BP-PsO group). They compared the average age of BP onset, overall disease activity, and immunological markers. Serum IL-17A and IL-13 levels were measured, and flow cytometry was used to analyze peripheral blood mononuclear cells (PBMCs) for CD4+ IL-17A+ cells and IL-17A+ T follicular helper cells to assess cellular immune responses.
Results
The average age of bullous pemphigoid onset was significantly lower in the BP-PsO group (median [IQR]: 67.00 [58.00-75.75] years) compared to the BP alone group (median [IQR]: 75.00 [64.00-82.00] years) (p=0.021). In the BP-PsO group, 21 patients (87.5%) presented with coexisting active psoriatic plaques and BP lesions. While overall BP disease activity and typical immunological features were comparable between groups, a distinct inflammatory signature emerged. > Serum IL-17A level was significantly elevated in the BP-PsO group (median [IQR]: 18.29 [10.39-43.50] pg/mL), compared with the BP alone group (median [IQR]: 10.36 [9.16-12.11] pg/mL) and psoriasis alone groups (median [IQR]: 11.65 [10.10-12.78] pg/mL). This elevated IL-17A correlated with disease activity. Flow cytometry further confirmed an enhanced IL-17A response in PBMCs from the BP-PsO group, showing an elevated proportion of CD4+ IL-17A+ cells and IL-17A+ T follicular helper cells versus controls. IL-13 levels were comparably elevated in both BP-PsO and BP alone groups relative to psoriasis alone and healthy controls.
Key Findings
- BP onset was significantly earlier in BP-PsO patients (median 67.00 years) vs. BP alone (75.00 years, p=0.021).
- Serum
IL-17Alevels were significantly elevated in BP-PsO patients (median 18.29 pg/mL) compared to BP alone (10.36 pg/mL) and PsO alone (11.65 pg/mL). - Enhanced
IL-17Aresponse inPBMCsfrom BP-PsO patients, with increasedCD4+ IL-17A+andIL-17A+ T follicular helper cells. - Inhibition of
IL-17Aled to concurrent remission of both diseases in a representative case. - BP with psoriasis represents a distinct clinical entity characterized by a predominant
IL-17Asignature.
Why It Matters
This study identifies a distinct IL-17A-driven inflammatory signature in patients with co-occurring bullous pemphigoid and psoriasis, suggesting a shared pathogenic pathway. Targeting IL-17A could offer a novel therapeutic strategy for managing both conditions concurrently, potentially leading to more effective and less broadly immunosuppressive treatments. The finding of earlier BP onset in patients with psoriasis also highlights the importance of early screening and proactive management in this high-risk population. This research paves the way for clinical trials investigating IL-17A inhibitors, already approved for psoriasis, as a dual-purpose therapy for BP-PsO patients, moving closer to a precision medicine approach for these complex autoimmune dermatoses.
bullous pemphigoid
psoriasis
il-17a
autoimmune
skin disease
inflammation