Both CD8+ and CD4+ T Cells Contribute to Corneal Clouding and Viral Clearance following Vaccinia Virus Infection in C57BL/6 Mice

Dry eye disease caused by viral infection: Past, present and future

Following viral infection, the innate immune system senses viral products, such as viral nucleic acids, to activate innate defence pathways, leading to inflammation and apoptosis, control of cell proliferation, and consequently, threat to the whole body. The ocular surface is exposed to the external environment and extremely vulnerable to viral infection. Several studies have revealed that viral infection can induce inflammation of the ocular surface and reduce tear secretion of the lacrimal gland (LG), consequently triggering ocular morphological and functional changes and resulting in dry eye disease (DED). Understanding the mechanisms of DED caused by viral infection and its potential therapeutic strategies are crucial for clinical interventional advances in DED. This review summarizes the roles of viral infection in the pathogenesis of DED, applicable diagnostic and therapeutic strategies, and potential regions of future studies.

Increased Neutrophil Percentage and Neutrophil-T Cell Ratio Precedes Clinical Onset of Experimental Cerebral Malaria

Newly emerging data suggest that several neutrophil defense mechanisms may play a role in both aggravating and protecting against malaria. These exciting findings suggest that the balance of these cells in the host body may have an impact on the pathogenesis of malaria. To fully understand the role of neutrophils in severe forms of malaria, such as cerebral malaria (CM), it is critical to gain a comprehensive understanding of their behavior and functions. This study investigated the dynamics of neutrophil and T cell responses in C57BL/6 and BALB/c mice infected with Plasmodium berghei ANKA, murine models of experimental cerebral malaria (ECM) and non-cerebral experimental malaria, respectively. The results demonstrated an increase in neutrophil percentage and neutrophil-T cell ratios in the spleen and blood before the development of clinical signs of ECM, which is a phenomenon not observed in the non-susceptible model of cerebral malaria. Furthermore, despite the development of distinct forms of malaria in the two strains of infected animals, parasitemia levels showed equivalent increases throughout the infection period evaluated. These findings suggest that the neutrophil percentage and neutrophil-T cell ratios may be valuable predictive tools for assessing the dynamics and composition of immune responses involved in the determinism of ECM development, thus contributing to the advancing of our understanding of its pathogenesis.

Novel severe oculocutaneous manifestations of human monkeypox virus infection and their historical analogues

WHO has declared human mpox (formerly known as monkeypox) a global public health emergency since July, 2022. When case numbers were increasing, so did clinicians' exposures to new elements of the disease. Additionally, the burden of mpox is particularly apparent in immunocompromised patients, who can have more variable and severe manifestations of disease across organ systems. In this Grand Round, we report novel and severe oculocutaneous manifestations of mpox in this population, which are both sight and life threatening. Specifically, we highlight two patients with mpox and AIDS who had refractory skin necrosis that progressed to either ocular compromise or panfacial gangrene, or both. Both patients ultimately died due to systemic complications of their infections. Through clinical analogies, we show how past experiences with related orthopoxviruses, such as variola virus (smallpox) and vaccinia virus, can add useful context for understanding and treating these new disease states. We suspect that in patients who are immunocompromised, monkeypox virus can clinically evolve not only via viraemia but also through direct intradermal spread. We propose that intradermal spread occurs by a process clinically and immunologically analogous to progressive vaccinia, a complication previously seen after conventional smallpox vaccination. We share evidence in support of this theory and implications regarding early management and post-exposure prophylaxis for at-risk populations. Content note: this Grand Round contains graphic images of mpox lesions of the eyes and face.