Acute HIV-1 infection presenting with fulminant encephalopathy

Jejunal epithelial barrier disruption triggered by reactive oxygen species in early SIV infected rhesus macaques

Intestinal epithelial barrier destruction occurs earlier than mucosal immune dysfunction in the acute stage of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections. At present, however, the cause of compromised gastrointestinal integrity in early SIV infection remains unknown. In the current study, we investigated the effects of SIV infection on epithelial barrier integrity and explored oxidative stress-mediated DNA damage and apoptosis in epithelial cells from early acute SIVmac239-infected Chinese rhesus macaques (Macaca mulatta). Results showed that the sensitive molecular marker of small intestinal barrier dysfunction, i.e., intestinal fatty acid-binding protein (IFABP), was significantly increased in plasma at 14 days post-SIV infection. SIV infection induced a profound decrease in the expression of tight junction proteins, including claudin-1, claudin-3, and zonula occludens (ZO)-1, as well as a significant increase in the active form of caspase-3 level in epithelial cells. RNA sequencing (RNA-seq) analysis suggested that differentially expressed genes between pre- and post-SIV-infected jejuna were enriched in pathways involved in cell redox homeostasis, oxidoreductase activity, and mitochondria. Indeed, a SIV-mediated increase in reactive oxygen species (ROS) in the epithelium and macrophages, as well as an increase in hydrogen peroxide (H₂O₂) and decrease in glutathione (GSH)/glutathione disulfide (GSSG) antioxidant defense, were observed in SIV-infected jejuna. In addition, the accumulation of mitochondrial dysfunction and DNA oxidative damage led to an increase in senescence-associated β-galactosidase (SA-β-gal) and early apoptosis in intestinal epithelial cells. Furthermore, HIV-1 Tat protein-induced epithelial monolayer disruption in HT-29 cells was rescued by antioxidant N-acetylcysteine (NAC). These results indicate that mitochondrial dysfunction and oxidative stress in jejunal epithelial cells are primary contributors to gut epithelial barrier disruption in early SIV-infected rhesus macaques.

Neurologic Complications of Acute HIV Infection

Purpose of Review

This review focuses on the pathophysiology of acute HIV infection (AHI) and related central nervous system (CNS) pathology, the clinical characteristics of neurologic complications of AHI, and the implications of the CNS reservoir and viral escape for HIV treatment and cure strategies.

Recent Findings

Recent studies in newly seroconverted populations show a high prevalence of peripheral neuropathy and cognitive dysfunction in AHI, even though these findings have been classically associated with chronic HIV infection. HIV cure strategies such as the "shock and kill" strategy are currently being studied in vitro and even in small clinical trials, though the CNS as a reservoir for latent HIV poses unique barriers to these treatment strategies.

Summary

Limited point of care diagnostic testing for AHI and delayed recognition of infection continue to lead to under-recognition and under-reporting of neurologic manifestations of AHI. AHI should be on the differential for a broad range of neurological conditions, from Bell's palsy, peripheral neuropathy, and aseptic meningitis, to more rare manifestations such as ADEM, AIDP, meningo-radiculitis, transverse myelitis, and brachial neuritis. Treatment for these conditions involves early initiation of antiretroviral therapy (ART) and then standard presentation-specific treatments. Current HIV cure strategies under investigation include bone marrow transplant, viral reservoir re-activation and eradication, and genome and epigenetic viral targeting. However, CNS penetration by HIV-1 occurs early on in the disease course with the establishment of the CNS viral reservoir and is an important limiting factor for these therapies.

Management of HIV-infected patients in the intensive care unit

The widespread use of combination antiretroviral therapies (cART) has converted the prognosis of HIV infection from a rapidly progressive and ultimately fatal disease to a chronic condition with limited impact on life expectancy. Yet, HIV-infected patients remain at high risk for critical illness due to the occurrence of severe opportunistic infections in those with advanced immunosuppression (i.e., inaugural admissions or limited access to cART), a pronounced susceptibility to bacterial sepsis and tuberculosis at every stage of HIV infection, and a rising prevalence of underlying comorbidities such as chronic obstructive pulmonary diseases, atherosclerosis or non-AIDS-defining neoplasms in cART-treated patients aging with controlled viral replication. Several patterns of intensive care have markedly evolved in this patient population over the late cART era, including a steady decline in AIDS-related admissions, an opposite trend in admissions for exacerbated comorbidities, the emergence of additional drivers of immunosuppression (e.g., anti-neoplastic chemotherapy or solid organ transplantation), the management of cART in the acute phase of critical illness, and a dramatic progress in short-term survival that mainly results from general advances in intensive care practices. Besides, there is a lack of data regarding other features of ICU and post-ICU care in these patients, especially on the impact of sociological factors on clinical presentation and prognosis, the optimal timing of cART introduction in AIDS-related admissions, determinants of end-of-life decisions, long-term survival, and functional outcomes. In this narrative review, we sought to depict the current evidence regarding the management of HIV-infected patients admitted to the intensive care unit.

Critically Ill Patients With HIV: 40 Years Later

The development of combination antiretroviral therapies (cARTs) in the mid-1990s has dramatically modified the clinical presentation of critically ill, HIV-infected patients. Most cART-treated patients aging with controlled HIV replication are currently admitted to the ICU for non-AIDS-related events, mostly bacterial pneumonia and exacerbation of comorbidities, variably affected by chronic HIV infection (COPD, cardiovascular diseases, or solid neoplasms). Today, Pneumocystis jirovecii pneumonia, cerebral toxoplasmosis, TB, and other severe opportunistic infections only occur in patients with unknown viral status, limited access to cART, viral resistance, or compliance issues. Acute respiratory failure, neurological disorders, and sepsis remain the main conditions that lead HIV-infected patients to the ICU, although admissions for liver diseases or acute kidney injury are increasing. Case fatality dropped substantially over the past decades, reaching figures of HIV-uninfected critically ill patients with similar demographic characteristics, comorbidities, and level of organ dysfunctions. Several other facets of critical care management have evolved in this population, including diagnostic procedures, cART management at the acute phase of critical illness, and ethical considerations. The goal of this narrative review was to depict the current evidence and emerging challenges for the management of critically ill, HIV-infected patients, almost 40 years following the onset of the AIDS epidemic.

CXCL13 as a diagnostic marker of neuroborreliosis and other neuroinflammatory disorders in an unselected group of patients

BACKGROUND

The C-X-C motif chemokine ligand 13 (CXCL13) and its receptor CXCR5 play an important role in the homing of B-lymphocytes. As a biomarker in the cerebrospinal fluid (CSF), CXCL13 has increasingly been used for the diagnosis of neuroborreliosis (NB). We evaluated the diagnostic and prognostic potential of CXCL13 for NB and other neuroinflammatory diseases in an unselected cohort, paying attention to those patients particularly who might benefit from newly emerging CXCL13-directed therapies.

METHODS

We report the CSF CXCL13 concentrations and other relevant baseline characteristics for an unselected cohort of 459 patients. We compare different diagnostic groups and analyse the sensitivity and specificity of CSF CXCL13 as a marker of NB. The course of the CXCL13 concentrations is reported in a subgroup of 19 patients.

RESULTS

We confirm the high diagnostic yield of CXCL13 for NB in this unselected cohort. The optimal cut-off for the reliable diagnosis of NB was 93.83 pg/ml, resulting in a sensitivity and specificity of 95 and 97%, respectively (positive predictive value 55.9%, negative predictive value 99.8%), surpassing the sensitivity of both serological testing and PCR. CSF CXCL13 concentration showed a swift response to therapy. Non-NB patients with high CSF CXCL13 concentrations suffered from meningeosis neoplastica or infectious encephalitis.

CONCLUSIONS

CXCL13 is a valuable tool for the diagnosis and assessment of therapeutic response in NB. Furthermore, our data point towards an emerging role of CXCL13 in the diagnosis and prognosis of viral encephalitis and meningeosis neoplastica. These results are of particular interest in the light of recently developed approaches to CXCL13-directed therapeutic interventions.