Figure 7.

Summary of main differences in the phenotype of CD4+T cells comparing young-old-old/interstitial lung abnormalities (ILA). The decrease of the frequency of naïve and the increase of memory CD4+T cells, as well as the loss of the co-stimulatory molecule CD27 and the gain of the ‘brake molecule’ KLRG1 is considered a normal process in ageing, as illustrated when compare young versus old persons. By contrast, our data showed that old/ILA does not show this typical phenotype profile, when compared with old controls; actually, old/ILA is characterised by increased frequency of naïve and decreased frequency of memory CD4+T cells, and these cells do not lose the expression of CD27 and do not express KLRG1. KLRG1, killer-cell lectin-like receptor G1; MFI, mean fluorescence intensity; PD-1, programmed cell death 1; T_CM, central memory; T_EM, effector memory; TEMRA, effector memory RA.