Immunohistochemical Characterisation of the Interstitial Inflammatory Environment: T-Cell- and B-Cell-Dominant Subtypes of Hidradenitis Suppurativa.

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease with a complex immune response. Given the considerable heterogeneity of the clinical phenotype of HS, this study aimed to analyse the immunohistochemical pattern of interstitial inflammation.

METHODS

Immunohistochemical analysis was performed on skin samples from 49 patients with HS. The immunohistochemical markers CD3, CD4 and CD8 for T-cells, CD20 for B-cells, CD138 for plasma cells and CD30, CD56, Bcl-2 and Bcl-6 were stained on lesional skin.

RESULTS

The analysis of immune cell dominance in patients with HS revealed that 33.3% of the cohort exhibited B-cell dominance, defined as a ratio of the sum of CD20+ and CD138+ cells to CD3+ cells greater than 1, while the majority (66.7%) demonstrated T-cell dominance, defined as a ratio of CD3+ cells to the sum of CD20+ and CD138+ cells greater than 1. B-cell-dominant HS is associated with a significantly elevated probability of mammary involvement (13.3% vs. 0%; p = 0.041). T-cell-dominant HS patients tended to demonstrate a higher mean tobacco consumption, but not significantly (20 vs. 5 tobacco pack-years; p = 0.06). CD4-dominant HS patients exhibited a significantly greater involvement of the mons pubis (62.5% vs. 28.6%, p = 0.023) compared to CD8-dominant patients, who demonstrated a significantly higher number of abscesses (p = 0.027).

CONCLUSIONS

For the first time, we describe the clinical and immunohistochemical characteristics of T-cell- and B-cell-dominant HS. Although HS seems to be more dominated by T-cells, a B-cell dominance was found in 33% of cases.