Viral transmission and pathogenesis in human tissues

Eunice Kennedy Shriver National Institute Of Child Health & Human Development

Investigators

Linked publications & trials

Abstract

1. We characterized the cytokine network in blood and semen in individuals longitudinally sampled before they began ART and after achieving suppression of HIV-1 RNA. We evaluated concentrations of 34 cytokine/chemokines using a multiplex bead-based assay in blood and seminal plasma of 19 men with HIV-1 prior to and after viral suppression. While in blood, the cytokine spectra were fairly similar before and after viral suppression, in semen the immunological landscapes were very different before and after ART in the male genital compartment. Four cytokines (MIG, IL-15, IL-7 and ITAC) were different across timepoints in semen and two were different in blood (MIG and IP-10). We also investigated the sex differences in plasma cytokine profiles in men and women with chronic HIV on suppressive antiretroviral therapy (ART) by measuring the concentrations of 36 cytokine/ chemokines. We found that IL-7 and 4 inflammatory chemokines were higher in women on suppressive ART compared with men on suppressive ART. Thus, inflammatory cytokines remain higher in virologically suppressed women compared with men living with HIV-1, suggesting that cytokines contribute to maintaining higher immune activation in women despite suppressive therapy with ART. What drives immune activation in both men and women under ART remains to be understood. Cytomegalovirus (CMV) is considered to be one of the driving forces of persistent immune activation. Although the associations between CMV replication and systemic inflammation in people living with HIV-1 (PWH) during suppressive ART have been well documented, it not clear whether CMV replication is associated with systemic immune activation already during the earliest phase of untreated HIV-1 infection, thus being a potential target for early CMV intervention. We investigated whether genital CMV shedding contributed to systemic immune activation as evaluated by the concentration of 34 blood cytokines in PWH in the acute/early phase of HIV-1 infection. Our results suggest that CMV shedding in male genital tract is not the main driver of systemic immune activation in early phase of HIV-1 infection in contrast with the later phase of HIV-1 infection. Similar studies in women should reveal, whether there is a sex-related difference in the role of CMV in early infection. Whatever is the role of CMV in HIV acquisition, our results on cytokine distribution may already explain why women progress faster to AIDS compared with men at a given viral load. 2. We studied EVs in the blood of people living with HIV under ART. The majority of EVs in blood are released by platelets that are activated in the course of HIV infection. We found a significant increase in the number of circulating platelet-derived EVs during HIV infection. This elevation was not related to viro-immunological status or to administration of ART. Some EVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls, probably due to defective mitophagy. In this context, EVs may serve as biomarkers of platelet activation, possibly reflecting pathogenesis even in the absence of HIV-1 replication. EVs can serve as biomarkers in complicated pregnancies as well. In particular, we found that the composition of EVs in maternal blood are significantly changed in cases of fetal death compared to gestational age matched uncomplicated or preeclampsia complicated pregnancies. Sixteen soluble proteins were significantly different between fetal death and controls, and eight proteins were different in EVs including PIGF, MIF, ADAM12, PTX3, IL16, IL6, MMP-1 and CD163. While there was overlap in proteins unregulated in soluble and EV form, several of these proteins were found to be unregulated only in EVs making them potential candidates for biomarkers. Furthermore, we investigated the associations between EV-associated and soluble cytokines with immune markers and symptom clusters in men with non-metastatic prostate cancer. Both EV-associated and soluble forms of RANTES significantly correlated with the symptom cluster for external beam radiation therapy (EBRT) at the start of treatment, whereas, three months post-treatment, soluble IFN2, IL-9, and IL-17 correlated with the corresponding symptom cluster. For men in the active surveillance group, soluble survivin correlated with psychoneurological symptoms. Linking specific inflammatory cytokines with psychoneurological symptom clusters in men receiving prostate cancer treatment can enhance understanding of the underlying mechanisms of this phenomenon and aid in developing targeted interventions. 3. To evaluate the efficiency of prevention of cytokine storm by tocilizumab, we analyzed cytokine profiles and their interrelation in regard to anti-cytokine treatment with tocilizumab in patients with COVID-19. Specifically, we analyzed the patient groups separated in two ways: according to the clusterization of their blood cytokines and based on the administration of tocilizumab therapy. Patients with and without cytokine storm formed distinct clusters according to their cytokine concentration changes. However, the tocilizumab therapy, administered based on the standard clinical and laboratory criteria, did not fully correspond to those clusters of cytokine storm syndrome. Only IL-1RA was prognostically significant in both groups of patients with and without tocilizumab therapy, decreasing in the former and increasing in the latter during the follow-up period. Thus, cytokine storm in COVID-19, characterized by a correlated release of multiple cytokines, does not fully correspond to the standard parameters of disease severity. Further investigation of SARS-CoV-2 infection in general and its effect on cytokines require the development of laboratory-controlled tissue model to investigate viral pathogenesis. We developed such a model based on human lung tissue ex vivo. This tissue model supports SARS-CoV-2 replication that triggers release of cytokines somewhat similar to those release in infected patients.