
There are many clinically validated targets that drive pathogenic inflammation in spondyloarthritis, including IL-17, TNF, IL-12*, IL-23* and JAK-STAT.1–3
What are the cytokines implicated in SpA pathobiology?
IL-17A and IL-17F are pivotal drivers of inflammation in PsA, axSpA, PSO and HS.4–7 They share overlapping biology,8–14 and can be produced by multiple lymphocyte subsets, a process which can be independent of IL-23.2,15,16
IL-17A and IL-17F:
Form homodimers and heterodimers9,10
Use the same receptor complex11,12
Are both expressed at sites of inflammation in PsA, axSpA, PSO, and HS4,7,13,14,17,18

Figure adapted from references8–14
However, IL-17A and IL-17F are also regulated and expressed differently:

Regulation
STAT5 induces preferential expression of IL-17F over IL-17A, whereas STAT3 enhances IL-17A over IL-17F20

Kinetics
Over time IL-17F becomes the dominant cytokine expressed by Th17 cells20†

Target Tissue Expression
IL-17F expression is high relative to IL-17A in tissues and in vitro models of PsA and axSpA20–22
†IL-17A is more potent than IL-17F in human skin cells, whilst IL-17F is more abundant than IL-17A in patients with psoriasis.21 CD4+ T cells stimulated with anti-CD3 and anti-CD28 in addition to brefeldin A between 0–72 hours.20
What disease manifestations are these cytokines implicated in?
Explore our resources below to find out the answers to this question and more today.
*Validated for PsA but failed for axSpA.1
EU-DC-2400159
Date of preparation: February 2025