I've read most older adults in Canada have multiple chronic illnesses which has the potential to effect the immune system. Although ageing and frailty are not always associated, multiple complex issues effecting the mind and body can create a ripple effect in other areas.

Two articles that could support your question are below. Good luck!

http://www.scielo.br/readcube/epdf.php?doi=10.1590/0001-3765201720160487&pid=S0001-37652017000100285&pdf_path=aabc/v89n1/0001-3765-aabc-89-01-00285.pdf&lang=en

Article Aging of the Immune System. Mechanisms and Therapeutic Targets

Thank you Stephanie, very kind. As you are able please see if you can get involved in studies which do the measurements based on nearness to death. Ta Rod

This paper just published in Immunity, isn't specifically on the last year of life, but may provide some interesting insights about the trajectory as we age - and new measurement possibilities.

Article High-Dimensional Single-Cell Mapping of Central Nervous Syst...

Many thanks Paul. Most apposite.

I have noted that during periods of unexplained higher deaths that those with AD and dementia have a higher risk of death. See http://www.hcaf.biz/2010/Publications_Full.pdf also

Jones R (2015) Unexpected Increase in Deaths from Alzheimer’s, Dementia and Other Neurological Disorders in England and Wales during 2012 and 2013. Journal of Neuroinfectious Diseases 6:172. doi: 10.4172/2314-7326.1000172

Jones R (2016) A presumed infectious event in England and Wales during 2014 and 2015 leading to higher deaths in those with neurological and other disorders. Journal of Neuroinfectious Diseases 7(1): 1000213 doi: 10.4172/2314-7326.1000213

Jones R, Goldeck D (2014) Unexpected and unexplained increase in death due to neurological disorders in 2012 in England and Wales: Is cytomegalovirus implicated? Medical Hypotheses 83(1): 25-31. http://dx. doi.org/10.1016/j.mehy.2014.04.016

i think this paper also could be useful,

Article Alzheimer's Disease: Targeting the Cholinergic System

Cholinergic System plays essential roles during infection or inflammatory diseases. macrophages and many other non-neuronal cells express nicotinic acetylcholine receptors, and agonistic stimulation of these receptore has anti-inflammatory effects.

bests

Thanks Davod!

Dear Rodney, Have you also looked at animal models?

Understanding How Dogs Age: Longitudinal Analysis of Markers of Inflammation, Immune Function, and Oxidative Stress. https://academic.oup.com/biomedgerontology/advance-article/doi/10.1093/gerona/glx182/4555010

Or mRNA changes in octagenarians vs centenarians?

Low expression of CD39 and CD73 genes in centenarians compared with octogenarians.

https://academic.oup.com/biomedgerontology/advance-article/doi/10.1093/gerona/glx182/4555010

Many thanks Paul

There are several factors that deteriorate last few years of life. Stem cell exhaustion, DNA damage accumulation, cellular senescence and declining immune system are mainly to blame. Several studies mentioned there is lymphoid to myeloid skewing in general in older mice.

here is the best review on hallmarks of ageing.

http://www.cell.com/cell/fulltext/S0092-8674(13)00645-4

Many thanks Seerat.

This is a great question. Although I have not much read when it comes to immunology and aging, I do expect a sharper decline in the immune system coupled with other systemic declines in the last year of the life of a human. Having said that we should also keep in mind that human body is a very complex machine with amazing ability to repair itself along with almost unpredictable vulnerability to any failure becoming fatal. In this context, we should not look at the immune system in isolation, but along with the other major systems, particularly, cardiovascular, neurological and renal.

Sandeep

Thank you Sandeep. What you have described is called Mosaic Ageing - the weakest part fails first. Indeed a complex system. Cheers Rod