Redox regulation of age-associated defects in generation and maintenance of T cell self-tolerance and immunity to foreign antigens

Thymic atrophy reduces naive T cell production and contributes to increased susceptibility to viral infection with age. Expression of tissue-restricted antigen (TRA) genes also declines with age and has been thought to increase autoimmune disease susceptibility. We find that diminished expression of a model TRA gene in aged thymic stromal cells correlates with impaired clonal deletion of cognate T cells recognizing an autoantigen involved in atherosclerosis. Clonal deletion in the polyclonal thymocyte population is also perturbed. Distinct age-associated defects in the generation of antigen-specific T cells include a conspicuous decline in generation of T cells recognizing an immunodominant influenza epitope. Increased catalase activity delays thymic atrophy, and here, we show that it mitigates declining production of influenza-specific T cells and their frequency in lung after infection, but does not reverse declines in TRA expression or efficient negative selection. These results reveal important considerations for strategies to restore thymic function.

Systemic lupus and catastrophic antiphospholipid syndrome manifesting as cardiogenic shock

In this case series we present two young female patients presenting in the peripartum period with cardiogenic shock. Both patients had underlying autoimmune diseases, one with systemic lupus erythematosus (SLE) and the other with antiphospholipid syndrome (APS). In both cases cardiogenic shock was a direct manifestation of their autoimmune condition, and with prompt diagnosis and management both patients were able to recover. This case series illustrates the importance of early recognition of cardiogenic shock as a rare manifestation both of SLE and APS.