Supplementary Material for: Serum Anticytokine Autoantibody Levels Are Not Increased in Hidradenitis Suppurativa: A Case-Control Pilot Study

<i>Background:</i> Hidradenitis suppurativa is a skin disease of recurrent episodes of inflammatory nodules, abscesses, and scarring of the intertriginous regions, e.g. the axillae and groin. A dysregulated immune response to one or more unknown antigens in hidradenitis suppurativa has been suggested. One hypothetical element of this dysregulation may be the functionality of the cytokines. This study examines the serum level of anticytokine autoantibodies for interleukin (IL)-1α, IL-6, IL-10, IL-17A, IL-17E, IL-17F, and interferon-α. <i>Method:</i> Recombinant, carrier-free cytokines were coupled to microspheres. The coupled beads were incubated for 1 h in the dark with assay buffer-diluted sera, and subsequently for 30 min with polyclonal goat F(ab′)2 anti-human IgG phycoerythrin-conjugated antibody. Data are presented as the median fluorescence intensity of samples. <i>Results:</i> No difference in levels of anticytokine autoantibodies was demonstrated for any of the autoantibodies studied. <i>Discussion:</i> The data suggest that endogenously produced autoantibodies only play a minor role, if any, in hidradenitis suppurativa.