<p>Pro‑inflammatory cytokines data for StD and HC.</p>

The StD group exhibited increased FC in three specific circuits: The left middle CC (MCC) to the bilateral caudate nucleus (CN); the left supracallosal anterior CC (supACC) to the bilateral anterior cerebellar lobe; the right supACC to the right superior frontal gyrus (SFG). Furthermore, serum concentrations of TNF-α, IL-1β, and IL-17 were significantly increased. FC between the left MCC and bilateral CN was associated with CES-D and RRS scores, whereas FC between the right supACC and right SFG was associated with HAMA scores.

Interaction between IL-1β and FC in the right supACC-SFG circuit was independently associated with HAMA scores, whereas interaction between IL-17 and FC in the same circuit independently predicted RRS scores. The statistical interaction between IL-1β and IL-17 levels and right supACC-SFG FC is associated with anxiety and rumination symptoms in StD, which may indicate an increased risk of progression to major depression.

These findings underscore the significance of neuroimmune associations in subthreshold depression.</p></div>