B Cells Compartment in Centenarian Offspring and Old People

Immunosenescence is considered a major contributory factor to the increased frequency of morbidity and mortality amongelderly. On the other hand centenarians are considered the best example of successful ageing. To gain insight into mechanisms ofimmunosenescence and its clinical relevance, a possible model is represented by centenarians and/or their offspring. Nowadayscentenarians are not more a curiosity, but in Europe are 1/8000 inhabitants and it has been demonstrated that the centenarian offspring,who are typically in their 70s and 80s, have a survival advantage when compared with age-matched controls whose parents died at anaverage life expectancy. Then again, studies on immunosenescence focus mainly on T cell impairment, although B cells are also affected.So, in the present preliminary report, we have studied B cell compartment in two classes of individuals, old people and centenarianoffspring. B cell compartment was analysed using anti-IgD and CD27 antibodies which characterize naïve B cells (IgD+ CD27-), memoryunswitched B cells (IgD+CD27+), memory switched B cells(IgD-CD27+) and double negative B cells (DN) (IgD-CD27-), i.e. exhaustedmemory cells. As expected, in both cohorts we observed a decreased B cell count. However, in centenarian offspring, naïve B cells aremore abundant whereas exhausted memory cells (DN B cells, IgD-CD27-) do not show the increase that we have previously demonstratedin healthy elderly donors. These data are similar to that found in previously experiments on young subjects. So, our preliminary resultsshow that centenarian offspring do not have the typical trend of memory/naive B cell subsets observed in elderly people and this is inagreement with the higher levels of IgM in the serum of centenarian offspring in comparison with data obtained in age-matched controls.This reservoir of naive B cell might be one of the causes that make centenarian offspring able to keep fighting off new infections, henceprolonging their life. So, B cell subset changes could represent a hallmark of successful or unsuccessful ageing and could be used as abiomarker of human life span, potentially useful for the evaluation of anti-ageing treatment.