Male BXSB mice develop a thymic hormonal dysfunction with presence of intraepithelial crystalline inclusions

The influence and impact of ageing and immunosenescence (ISC) on adaptive immunity during multiple sclerosis (MS) and the animal counterpart experimental autoimmune encephalomyelitis (EAE)

The human ageing process encompasses mechanisms that effect a decline in homeostasis with increased susceptibility to disease and the development of chronic life-threatening illness. Increasing age affects the immune system which undergoes a progressive loss of efficiency, termed immunosenescence (ISC), to impact on quantitative and functional aspects of innate and adaptive immunity. The human demyelinating disease multiple sclerosis (MS) and the corresponding animal model experimental autoimmune encephalomyelitis (EAE) are strongly governed by immunological events that primarily involve the adaptive arm of the immune response. MS and EAE are frequently characterised by a chronic pathology and a protracted disease course which thereby creates the potential for exposure to the inherent, on-going effects and consequences of ISC. Collective evidence is presented to confirm the occurrence of established and unendorsed biological markers of ISC during the development of both diseases. Moreover, results are discussed from studies during the course of MS and EAE that reveal a premature upregulation of ISC-related biomarkers which indicates untimely alterations to the adaptive immune system. The effects of ISC and a prematurely aged immune system on autoimmune-associated neurodegenerative conditions such as MS and EAE are largely unknown but current evaluation of data justifies and encourages further investigation.

Thymulin and its role in immunomodulation

Even though thymulin was isolated, sequenced and characterised some 20 years ago and later identified as a thymic hormone involved in immunomodulation, much more work is still required to further understanding of the mechanisms of action(s) of this peptide. Since the observation, by a semiquantitative bioassay, of diminished levels of thymulin in immunodeficiency and autoimmune disease, new data obtained by radioimmunoassay have not only confirmed previous observations but also demonstrated that thymulin plays a role in the interaction between the immune system and the neuro-endocrine system. In this paper we give an up to date account of recent developments in research into the role of thymulin in immunomodulation.

Thymic reticulum of autoimmune mice. II: Ultrastructural studies of mice with lupus-like syndrome (NZB, BXSB, MRL/l)

We examined the thymic reticulum of three strains of mice showing symptoms of lupus-like disease. Ultrastructural pathology revealed several features common to the three mouse strains in varying degrees according to sex and age of the mice. Main anomalies included vacuolized aspect of the thymic epithelium, an increased number of macrophages, interdigitating cells and cystic cavities, the presence of a great number of plasmocytes and mastocytes and extensive interstitial fibrosis and arteriosclerosis. The most intriguing finding was the presence of crystal-like inclusions in epithelial cells. Some thymuses also showed premature histologic modifications similar to those observed in the ageing involuted thymus. Dysfunction of the epithelial cell secretory system, accumulation of denatured thymic hormone as well as premature organ ageing associated with a loss of thymic function could contribute significantly to the autoimmune phenomenon observed in lupus mice.