Abnormal phenotypic distribution of regulatory and effector T cells in octogenarian and nonagenarian women

INTRODUCTION

aging is associated with several immunologic changes. Regulatory (Treg) and effector T cells are involved in the pathogenesis of infectious, neoplastic, and autoimmune diseases. Little is known about the effects of aging on the frequency and function of these T cell subpopulations.

METHODS

peripheral blood mononuclear cells (PBMC) were obtained from 26 young (under 44 years old) and 18 elderly (above 80 years old) healthy women. T cell subpopulations were analyzed by flow cytometry.

RESULTS

elderly individuals had lower frequency of several activated effector T cell phenotypes as compared with young individuals: CD3+CD4+CD25+ (3.82±1.93 versus 9.53±4.49; p<0.0001); CD3+CD4+CD25+CD127+(2.39±1.19 versus 7.26±3.84; p<0.0001); CD3+CD4+CD25+ (0.41±0.22 versus 1.86±0.85, p<0.0001); and CD3+CD4+CD25highCD127+(0.06±0.038 versus 0.94±0.64, p<0.0001). Treg (CD3+CD4+CD25+CD127øFoxp3+) presented lower frequency in elderly individuals as compared to young adults (0.34±0.18 versus 0.76±0.48; p=0.0004) and its frequency was inversely correlated with age in the whole group (r=-0.439; p=0.013). The elderly group showed higher frequency of two undefined CD25øFoxp3+ phenotypes: CD3+CD4+CD25øFoxp3+(15.05±7.34 versus 1.65±1.71; p<0.0001) and CD3+CD4+CD25øCD127øFoxp3+(13.0±5.52 versus 3.51±2.87; p<0.0001).

CONCLUSIONS

the altered proportion of different T cell subsets herein documented in healthy elderly women may be relevant to the understanding of the immunologic behavior and disease susceptibility patterns observed in geriatric patients.

RNA interference: a new alternative for rheumatic diseases therapy

RNA interference (RNAi) is a post-transcriptional gene silencing mechanism preserved during evolution. This mechanism, recently described, is mediated by small double-stranded RNAs (dsRNAs) that can specifically recognize a target mRNA sequence and mediate its cleavage or translational repression. The use of RNAi as a tool for gene therapy has been extensively studied, especially in viral infections, cancer, inherited genetic disorders, cardiovascular and rheumatic diseases. Together with data from human genome, the knowledge of gene silencing mediated by RNAi could allow a functional determination of virtually any cell expressed gene and its involvement in cellular functioning and homeostasis. Several in vitro and in vivo therapeutic studies with autoimmune disease animal models have been carried out with promising results. The pathways of tolerance breakage and inflammation are potential targets for RNAi therapy in inflammatory autoimmune diseases. This review will present the basic principles of RNAi and discuss several aspects of RNAi-based therapeutic approaches, from in vitro tool design and target identification to in vivo pre-clinical drug delivery, and tests of autoimmune diseases in human cells and animal models. Finally, this review will present some recent clinical experience with RNAi-based therapy.

Immune system: part III. The delicate balance of the immune system between tolerance and autoimmunity

The immune system consists of an intricate network of organs, cells, and molecules responsible for maintaining the body's homeostasis and responding to aggression in general. Innate immunity operates in conjunction with adaptive immunity and is characterized by rapid response to aggression, regardless of previous stimulus, being the organism first line of defense. Its mechanisms include physical, chemical and biological barriers, cellular components, as well as soluble molecules. The organism first line of defense against tissue damage involves several steps closely integrated and constituted by different components of this system. The aim of this review is to restore the foundations of this response, which has high complexity and consists of several components that converge to articulate the development of adaptive immune response. We selected some of the following steps to review: perception and molecular recognition of aggressive agents; activation of intracellular pathways, which result in vascular and tissue changes; production of a myriad of mediators with local and systemic effects on cell activation and proliferation, synthesis of new products involved in the chemoattraction and migration of cells specialized in destruction and removal of offending agent; and finally, tissue recovery with restoration of functional tissue or organ.

Immune system - part II: basis of the immunological response mediated by T and B lymphocytes

The immune system consists of an intricate network of organs, cells, and molecules responsible for maintaining the body's homeostasis and responding to aggression in general. Innate immunity operates in conjunction with adaptive immunity and is characterized by rapid response to aggression, regardless of previous stimulus, being the organism first line of defense. Its mechanisms include physical, chemical and biological barriers, cellular components, as well as soluble molecules. The organism first line of defense against tissue damage involves several steps closely integrated and constituted by different components of this system. The aim of this review is to restore the foundations of this response, which has high complexity and consists of several components that converge to articulate the development of adaptive immune response. We selected some of the following steps to review: perception and molecular recognition of aggressive agents; activation of intracellular pathways, which result in vascular and tissue changes; production of a myriad of mediators with local and systemic effects on cell activation and proliferation, synthesis of new products involved in the chemoattraction and migration of cells specialized in destruction and removal of offending agent; and finally, tissue recovery with restoration of functional tissue or organ.