Eye on cytomegalovirus: Unveiling the ophthalmic impact of cytomegalovirus

Table 2 The mechanisms of cytomegalovirus reactivation

Mechanism	Description	Ref.
Direct suppression of immune cells	CMV interferes with the functionality and control of the host immune system through the direct suppression of certain immune cells	Fornara et al[13]
Alteration in cytokine proliferation	CMV alters the proliferation of cytokines, impacting the immune response	Compton et al[14]
Downregulation of MHC	CMV downregulates MHC expressed on the surface of viral-laden cells, impairing immune recognition	Vancíková and Dvorák[15], Gabor et al[16], Park et al[17], Howard and Najarian[18]
Altered production of proinflammatory cytokines	Reactivation involves the altered production of proinflammatory cytokines such as IL-1, IL-6, and tumour necrosis factor-alpha	Chinta et al[24]
Suppression of T-cell response	Immune-modulating diseases and drugs suppress T-cell response, contributing to reactivation	Chinta et al[24], Döcke et al[25]
Altered Treg action	Changes in Treg action affect immune regulation and promote reactivation	Chinta et al[24], Döcke et al[25]
Induction of transcription factors	Reactive oxygen species induce transcription factors like activator protein-1 and nuclear factor kappa B, leading to gene expression changes associated with CMV reactivation	Janeway et al[26], Heald-Sargent et al[27], Dhar et al[28]
DNA hypomethylation	Hypomethylation of DNA impacts gene expression and can contribute to the reactivation of CMV	Pshenichkin et al[29]
Effects of HSP	Destructive effects of HSPs facilitate reactivation	Boom et al[30]
Stress and chronic inflammatory response	Stress and chronic inflammation alter biochemical cascades, leading to reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]
Pregnancy	Pregnancy-induced changes in the immune system can trigger reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]
Immune-modulating drugs	Drugs that modulate the immune system can contribute to reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]
Nutritional deficiency	Lack of essential nutrients impacts immune function and may lead to reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]
Aging	Age-related decline in immune function increases the risk of reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]
Co-morbidities (e.g., diabetes, HIV/AIDS)	Co-existing health conditions like diabetes and HIV/AIDS alter immune responses and facilitate reactivation	Iwatani et al[20], Mariotti et al[21], Cook et al[22], Hanaoka et al[23]

AIDS: Acquired immune deficiency syndrome; CMW: Cytomegalovirus; HIV: Human immunodeficiency virus; HSP: Heat shock proteins; IL: Interleukin; MHC: Major histocompatibility complex; Treg: Regulatory T-cell.