Short-chain fatty acid (SCFA) deficiency, particularly butyrate, drives aberrant plasmablast differentiation in SLE via GPR43 signaling, suppressing NF-κB phosphorylation and PRDM1 promoter binding through β-arrestin 2 activation.
Serum butyrate levels were significantly decreased in untreated patients with active SLE compared with healthy controls.
SCFAs inhibited plasmablast differentiation in human B cells through GPR43 signaling.
Butyrate or a GPR43 agonist activated β-arrestin 2, which suppressed NF-κB phosphorylation and reduced NF-κB binding to the PRDM1 promoter.
Gut dysbiosis is considered a key environmental factor in SLE, and serum SCFA levels are influenced by diet and gut environment.
Fine-tuning GPR43 signaling is proposed as a novel therapeutic strategy for SLE.
This research suggests that people with active, untreated lupus (SLE) have significantly lower blood levels of butyrate, a beneficial molecule produced when gut bacteria break down dietary fiber. Specifically, lupus patients had about 58% less butyrate in their blood compared to healthy individuals. Butyrate belongs to a family of molecules called short-chain fatty acids (SCFAs), which are known to have anti-inflammatory properties. The large difference observed (Cohen's d = 2.40) suggests this is a substantial and meaningful reduction, not just a minor variation. The study also uncovered how this butyrate deficiency may contribute to lupus. In lupus, the immune system produces too many 'plasmablasts' — cells that make large amounts of antibodies, including the self-targeting antibodies that drive lupus symptoms. This research found that SCFAs like butyrate normally put the brakes on plasmablast formation by activating a cell-surface receptor called GPR43. When GPR43 is activated, it triggers a chain reaction inside B cells (the immune cells that become plasmablasts) that ultimately blocks a key gene switch needed for plasmablast development. When SCFAs are low, this braking mechanism is weakened, potentially allowing the runaway plasmablast production seen in lupus. This research suggests that the connection between gut health and lupus may be partly explained by lower levels of beneficial bacterial byproducts like butyrate. Since SCFA levels can potentially be influenced by diet and the composition of gut bacteria, this opens the door to exploring whether dietary changes, probiotics, or drugs that mimic SCFAs by activating GPR43 could help control lupus disease activity. The authors note that dietary and gut environment factors were not directly studied here, so future research would need to explore whether interventions that raise SCFA levels or activate GPR43 could translate into clinical benefit for lupus patients.
Kanda R, Kubo S, Yamagata K, Iwata S, Todoroki Y, Ueno M, et al.. (2026). Short-chain fatty acid deficiency drives aberrant B cell differentiation in systemic lupus erythematosus.. Clinical immunology (Orlando, Fla.). https://doi.org/10.1016/j.clim.2026.110706