Chlamydia psittaci (C. psittaci) is a gram-negative intracellular parasitic pathogenic bacterium that can infect avian and mammalian hosts, including humans. The detection of C. psittaci infections typically relies on traditional antigen-based immunoassays or serological testing that often lack sensitivity and/or specificity. Metagenomic next generation sequencing (mNGS) is an emerging tool for diagnosis.

To demonstrate that mNGS represents a valuable tool for rapid, sensitive, and accurate pathogen detection including C. psittaci infections.

Four cases of psittacosis pneumonia and one case of pediatric psittacosis meningitis were diagnosed between December 2019 and May 2020 using mNGS at Changzhou Second People’s Hospital affiliated to Nanjing Medical University. Patients’ clinical characteristics, manifestations, and treatment histories were retrospectively evaluated.

All five patients had a history of exposure to wild (psittacine or other birds) or domesticated birds (chickens). All patients had a high fever (> 39℃) and three of them (60%) experienced organ insufficiency during the disease. The laboratory data showed normal to slightly increased leucocyte and neutrophil counts, and elevated procalcitonin levels in all five cases, and very high C-reactive protein levels in psittacosis pneumonia patients. mNGS identified a potential pathogen, C. psittaci, in patients’ bronchoalveolar lavage fluid or cerebrospinal fluid. Computed tomography revealed lung air-space consolidation, pleural thickening, and effusion fluid buildup in psittacosis pneumonia cases, and an arachnoid cyst in the right temporal lobe of the pediatric psittacosis meningitis patient. All patients experienced complete recovery following the administration of targeted anti-chlamydia therapy.

This study not only demonstrated that mNGS represents a valuable tool for rapid, sensitive, and accurate pathogen detection, but also raised public health concerns over C. psittaci infections.

• Chlamydia psittaci
• Pneumonia
• Meningitis
• Metagenomic next generation sequencing
• Etiology
• Infectious disease

Emerging evidence suggests that reactive oxygen species (ROS) play a significant role in the pathogenesis of peripheral nerve damage. Our previous study indicated that human herpesvirus 7 (HHV7) induces Bell’s palsy. However, the specific mechanism underlying the effects of ROS in HHV7 infection-induced facial nerve damage is unknown. In this study, we established a rat FN model by inoculating an HHV7 virus solution. The facial grading score and LuxolFastBlue (LFB) staining were used to assess the success of the model. Using mRNA-sequencing analysis, we found that the expression of Complex IV Subunit 4 Isoform 2 (Cox4i2) increased in infected Schwann cells (SCs). Cox4i2 was suggested to increase COX activity, thereby promoting ROS production. The changes in the endogenous oxidant and antioxidant system were assessed, and the results showed that oxidative stress increased after HHV7 infection in vivo and in vitro. However, we found that oxidative injury was relieved after the transfection of shCox4i2 in HHV7-treated SCs by evaluating cell death, cell proliferation, and the ROS level as well as the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Furthermore, we hypothesised that Cox4i2 loss would attenuate HHV7-induced ferroptosis and apoptosis, which are closely related to ROS in SCs. Our research illustrated that the knockdown of Cox4i2 suppresses HHV7-induced RSC96 cell ferroptosis as well as apoptosis via the ERK signalling pathway. Overall, several in vitro and in vivo methods were adopted in this study to reveal the new mechanism of ROS-induced and Cox4i2-mediated apoptosis and ferroptosis in HHV7 infected SCs.

• COX4I2
• HHV7
• Schwann cells
• apoptosis
• ferroptosis

Cerebrospinal fluid analysis is an essential part of the diagnostic workup in various neurological disorders. Evidence of an intrathecal immunoglobulin synthesis, as demonstrated by Reiber’s diagram or the more sensitive oligoclonal bands (OCB), are typical for neuroinflammatory diseases, and normally not expected in non-inflammatory neurological diseases. Therefore, patients with non-inflammatory neurological diseases are often used in control groups in studies investigating autoimmune diseases of the central nervous system. However, data about the frequency of intrathecal immunoglobulin synthesis in non-inflammatory neurological disease are scarce. The cerebrospinal fluid (CSF) records of a total of 3622 patients were screened and 2114 patients included with presumably non-inflammatory neurological diseases like dementia, idiopathic peripheral neuropathy, motoneuron disease, stroke, and epileptic seizures. Evidence of an intrathecal immunoglobulin synthesis can be found with low frequency also in non-inflammatory neurological diseases. A much higher rate of patients showed intrathecal immunoglobulin synthesis as demonstrated by OCB than by Reiber’s diagram. In patients with disorders of the peripheral nervous system the frequency of OCB was much lower than in patients presenting with central nervous system manifestations. Evidence of an intrathecal immunoglobulin synthesis should not automatically lead to exclusion of non-inflammatory neurological diseases but should rather prompt the way to investigate for the origin of the intrathecal immunoglobulin synthesis.

• Reiber’s diagram
• biomarker
• cerebrospinal fluid
• intrathecal immunoglobulin production
• oligoclonal bands