Reviewed by Sarah Alter, Ph.D. — Scientific Affairs, OrganaBio. 15 years of immunology research spanning autoimmunity, cancer, and infectious disease. University of Miami Miller School of Medicine. Registered Patent Agent.
Ankylosing spondylitis (AS), now more broadly classified as radiographic axial spondyloarthritis (r-axSpA), is a chronic inflammatory arthritis defined by HLA-B27 association, axial joint inflammation, and new bone formation. The IL-17A/IL-23 axis is the dominant therapeutic target, with secukinumab, ixekizumab, and bimekizumab approved and multiple IL-23 inhibitors in late-stage trials. Disease-state PBMCs from AS donors provide IL-17-producing T cell populations, innate lymphoid cells, and HLA-B27-restricted immune phenotypes that cannot be modeled in healthy donor samples.
Immune Biology of AS Relevant to Therapeutic Development
HLA-B27 misfolding drives ER stress responses in antigen-presenting cells, activating IL-23 production. IL-23 expands Th17 cells and ILC3s that produce IL-17A, IL-17F, and IL-22, driving both inflammation and osteoproliferation. CD4+ Th17 cells and CD8+ Tc17 cells are both expanded in AS peripheral blood and are the primary effector populations tested in IL-17 pathway pharmacodynamic assays. ILC3s, which produce IL-17 and IL-22 independent of TCR signaling, are elevated in AS and are increasingly recognized as important therapeutic targets.
OrganaBio AS Donor Catalog
| Attribute | Available |
|---|---|
| HLA-B27 status | ✓ Documented per lot; B27+ and B27– donors available |
| Disease activity (BASDAI) | Available on select lots |
| Treatment status | NSAID-only, anti-TNF, anti-IL-17 (secukinumab, ixekizumab) documented |
| PBMC format | Cryopreserved; fresh on scheduled collection |
| Lot documentation | CoA, HLA-B27, diagnosis, medications, flow cytometry |
Key Cell Populations for AS Research
- Th17 cells (CD4+/RORγt+/IL-17A+): Expanded in AS peripheral blood; primary pharmacodynamic target for anti-IL-17 and anti-IL-23 therapies
- Tc17 cells (CD8+/IL-17A+): Expanded in HLA-B27+ donors; contribute to IL-17A production independent of CD4 compartment
- ILC3s (Lin–/NKp44+/RORγt+): Elevated in AS; TCR-independent IL-17 and IL-22 source; relevant to anti-IL-23 mechanism of action
- Myeloid dendritic cells: IL-23-producing APCs; HLA-B27-driven ER stress amplifies IL-23 secretion; target of IL-23 pathway inhibitors
- Regulatory T cells: Numerically present but functionally suppressed in active AS; restoration target for pipeline candidates
Research Applications
- IL-17A and IL-17F pharmacodynamic assays for secukinumab, ixekizumab, and bimekizumab (dual IL-17A/F)
- IL-23p19 inhibition studies: guselkumab, risankizumab, mirikizumab downstream IL-17 suppression in AS PBMCs
- HLA-B27-specific ER stress and IL-23 pathway characterization in myeloid cells
- ILC3 frequency and IL-17/IL-22 production assays in untreated and biologic-experienced AS donors
- Comparative Tc17 versus Th17 contribution to IL-17 pool in HLA-B27+ donors
- JAK inhibitor (upadacitinib, tofacitinib) target engagement: STAT3 phosphorylation in AS PBMCs