PT  - JOURNAL ARTICLE
AU  - Andrea Cortini
AU  - Ursula Ellinghaus
AU  - Talat H Malik
AU  - Deborah S Cunninghame Graham
AU  - Marina Botto
AU  - Timothy James Vyse
TI  - B cell OX40L supports T follicular helper cell development and contributes to SLE pathogenesis
AID  - 10.1136/annrheumdis-2017-211499
DP  - 2017 Dec 01
TA  - Annals of the Rheumatic Diseases
PG  - 2095--2103
VI  - 76
IP  - 12
4099  - http://ard.bmj.com/content/76/12/2095.short
4100  - http://ard.bmj.com/content/76/12/2095.full
SO  - Ann Rheum Dis2017 Dec 01; 76
AB  - Objectives TNFSF4 (encodes OX40L) is a susceptibility locus for systemic lupus erythematosus (SLE). Risk alleles increase TNFSF4 expression in cell lines, but the mechanism linking this effect to disease is unclear, and the OX40L-expressing cell types mediating the risk are not clearly established. Blockade of OX40L has been demonstrated to reduce disease severity in several models of autoimmunity, but not in SLE. We sought to investigate its potential therapeutic role in lupus.Methods We used a conditional knockout mouse system to investigate the function of OX40L on B and T lymphocytes in systemic autoimmunity.Results Physiologically, OX40L on both B and T cells contributed to the humoral immune response, but B cell OX40L supported the secondary humoral response and antibody affinity maturation. Our data also indicated that loss of B cell OX40L impeded the generation of splenic T follicular helper cells. We further show that in two models of SLE—a spontaneous congenic model and the H2-IAbm12 graft-versus-host-induced model—loss of B cell OX40L ameliorates the autoimmune phenotype. This improvement was, in each case, accompanied by a decline in T follicular helper cell numbers. Importantly, the germline knockout did not exhibit a markedly different phenotype from the B cell knockout in these models.Conclusions These findings contribute to a model in which genetically determined increased OX40L expression promotes human SLE by several mechanisms, contingent on its cellular expression. The improvement in pathology in two models of systemic autoimmunity indicates that OX40L is an excellent therapeutic target in SLE.