Lactate signalling leads to aggregation of immune-inflammatory hotspots and SLC5A12 blockade promotes their resolution

Ectopic lymphoid structures (ELS) are aggregates of lymphoid cells that often form within inflamed tissues in patients with autoimmune diseases, cancer, infectious diseases and cardiovascular conditions. These structures drive B cell maturation into memory B cells and plasma cells through B cell and T cell co-stimulation, and their role in pathogenesis is increasingly recognized. Understanding how ELS develop and persist in inflamed tissues is essential for elucidating the pathogenesis and treatment responses in diseases in which they have a prominent role. Here we show that metabolic pathways and specific metabolites, in particular lactate, are master regulators of ELS organization in Sjögren’s disease (SjD), the second-most common autoimmune rheumatic disease. Furthermore, inhibiting lactate uptake by lactate transporters, specifically by SLC5A12 blockade, represents a previously unappreciated checkpoint in autoimmune inflammatory diseases. This approach results in multidimensional pro-resolution effects, including reduced inflammatory cytokine levels, enhanced T cell egress from inflamed sites and diminished T cell and B cell areas and their segregation within ELS. Certo, Pontarini et al. provide insight into the metabolic requirements of ectopic lymphoid structure (ELS) assembly in the context of autoimmunity, and show that blocking lactate uptake by SLC5A12 offers therapeutic benefits in a mouse model of Sjögren’s disease.