HIV-specific T-lymphocyte responses that underlie IRIS are incomplete and largely remain hypothetical. Of the several mechanisms presented by the host to control host immunological damage, Treg cells are believed to play a critical role. Using the available experimental evidence, it is proposed that enormous synthesis of conventional FoxP3_-Th cells (responsive) often renders subjects inherently vulnerable to IRIS, whereas that of natural FoxP3⁺Treg cell synthesis predominate among subjects that may not progress to IRIS. We also propose that IRIS non-developers generate precursor T-cells with a high avidity to generate CD4+CD25+FoxP3+ Tregs whereas IRIS developers generate T-cells of intermediate avidity yielding Th0 cells and effector T-cells to mediate the generation of proinflammatory cytokines in response to cell-signaling factors (IL-2, IL-6 etc.). Researchers have shown that IL-10 Tregs (along with TGF-β, a known anti-inflammatory cytokine) limit immune responses against microbial antigens in addition to effectively controlling HIV replication, the prime objective of HAART. Although certain technical limitations are described herein, we advocate measures to test the role of Tregs in IRIS.

Dietary patterns have been identified as one of the most important modifiable risk factors for several non-communicable diseases, inextricably linked to the health span of older people. Poor dietary choices may act as triggers for immune responses such as aggravated inflammatory reactions and oxidative stress contributing to the pathophysiology of several ageing hallmarks. Novel dietary interventions are being explored to restore gut microbiota balance and promote overall health in ageing populations. Probiotics and, most recently, postbiotics, which are products of probiotic fermentation, have been reported to modulate different signalling biomolecules involved in immunity, metabolism, inflammation, and oxidation pathways. This review presents evidence-based literature on the effects of postbiotics in promoting healthy ageing and mitigating various age-related diseases. The development of postbiotic-based therapeutics and diet-based interventions within a personalised microbiota-targeted approach is proposed as a possible direction for improving health in the elderly population. Despite growing evidence, the data regarding their exact mechanistic pathways for antioxidant and immunomodulating activities remain largely unexplored. Expanding our understanding of the mechanistic and chemical determinants of postbiotics could contribute to disease management approaches, as well as the development of and optimisation of biotherapeutics.

Gut immune components are severely compromised among persons with AIDS, which allows increased translocation of bacterial lipopolysaccharides (LPS) into the systemic circulation. These microbial LPS are reportedly increased in chronically HIV-infected individuals and findings have correlated convincingly with measures of immune activation. Immune reconstitution inflammatory syndrome (IRIS) is an adverse consequence of the restoration of pathogen-specific immune responses in a subset of HIV-infected subjects with underlying latent infections during the initial months of highly active antiretroviral treatment (HAART). Whether IRIS is the result of a response to a high antigen burden, an excessive response by the recovering immune system, exacerbated production of pro-inflammatory cytokines or a lack of immune regulation due to inability to produce regulatory cytokines remains to be determined. We theorize that those who develop IRIS have a high burden of proinflammatory cytokines produced also in response to systemic bacterial LPS that nonspecifically act on latent mycobacterial antigens. We also hypothesize that subjects that do not develop IRIS could have developed either tolerance (anergy) to persistent LPS/tubercle antigens or could have normal FOXP3+ gene and that those with defective FOXP3+ gene or those with enormous plasma LPS could be vulnerable to IRIS. The measure of microbial LPS, anti-LPS antibodies and nonspecific plasma cytokines in subjects on HAART shall predict the role of these components in IRIS.

The Indian Journal of Pharmacology is an official organ of the Indian Pharmacological Society