Background The clinical improvement of hidradenitis suppurativa reported in a small number of patients with antitumour necrosis factor (anti-TNF)-α therapies supports the hypothesis for an altered immune response in these patients.
Objectives To evaluate the state of the innate and adaptive immune responses in patients with hidradenitis suppurativa.
Methods Fifty-three patients and six healthy controls were studied. Blood was sampled and subpopulations of lymphocytes were analysed by flow cytometry; monocytes were isolated and their function was evaluated from the concentrations of TNF-α and interleukin (IL)-6 in supernatants of cell cultures after triggering with endotoxins (lipopolysaccharides). TNF-α and IL-6 were estimated by an enzyme immunoassay.
Results CD3/CD8 lymphocytes were lower in patients with involvement of the perineum than in controls; patients with involvement of the breast had higher levels of natural killer (NK) cells than controls. A negative correlation was found between years lapsing since initial presentation of lesions of hidradenitis and the percentage of NK cells. Monocytes isolated from healthy volunteers were more active for the secretion of TNF-α and IL-6 than those of patients with hidradenitis suppurativa.
Conclusions A reduction in the percentage of NK cells over time and a lower monocyte response to triggering by bacterial components is observed in patients with hidradenitis suppurativa. Further research is needed to clarify if these changes are connected to an autoimmune mechanism in the pathogenesis of hidradenitis suppurativa.