An evaluation of the recognised systemic inflammatory biomarkers of chronic sub-optimal inflammation provides evidence for inflammageing (IFA) during multiple sclerosis (MS)

Abstract

The pathogenesis of the human demyelinating disorder multiple sclerosis (MS) involves the loss of immune tolerance to self-neuroantigens. A deterioration in immune tolerance is linked to inherent immune ageing, or immunosenescence (ISC). Previous work by the author has confirmed the presence of ISC during MS. Moreover, evidence verified a prematurely aged immune system that may change the frequency and profile of MS through an altered decline in immune tolerance. Immune ageing is closely linked to a chronic systemic sub-optimal inflammation, termed inflammageing (IFA), which disrupts the efficiency of immune tolerance by varying the dynamics of ISC that includes accelerated changes to the immune system over time. Therefore, a shifting deterioration in immunological tolerance may evolve during MS through adversely-scheduled effects of IFA on ISC. However, there is, to date, no collective proof of ongoing IFA during MS. The Review addresses the constraint and provides a systematic critique of compelling evidence, through appraisal of IFA-related biomarker studies, to support the occurrence of a sub-optimal inflammation during MS. The findings justify further work to unequivocally demonstrate IFA in MS and provide additional insight into the complex pathology and developing epidemiology of the disease.

Keywords: Biomarker; immune tolerance; immunosenescence; inflammageing; multiple sclerosis; premature immune ageing.

Fig 1

Loss of immune tolerance in an ageing immune system. T cells /B cells in primary lymphoid organs plus peripheral T cells express tolerance checkpoint proteins . Biological ageing-associated ISC causes a decline in immune tolerance. Self-reactive immune cells develop and recruit inflammatory cells . Tissue-dependent autoimmune reactions and destructive mechanisms evolve

Fig. 2

The effects of stressor-induced IFA on the dynamics of ISC and immune tolerance. Inherent ISC, as a consequence of biological ageing, influences the rate of immune ageing and immune tolerance. Stressor-activated IFA stimulates SASP release and prematurely accelerates ISC with a decline in immune tolerance and an increased frequency of autoimmune disease.