Novel Immune-Related Genetic Expression for Primary Sjögren's Syndrome

Objective: To identify novel immune-related genes expressed in primary Sjögren's syndrome (pSS).Methods: Gene expression profiles were obtained from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were screened. The differences in immune cell proportion between normal and diseased tissues were compared, weighted gene co-expression network analysis was conducted to identify key modules, followed by a protein–protein interaction (PPI) network generation and enrichment analysis. The feature genes were screened and verified using the GEO datasets and quantitative real-time PCR (RT-qPCR).Results: A total of 345 DEGs were identified, and the proportions of gamma delta T cells, memory B cells, regulatory T cells (Tregs), and activated dendritic cells differed significantly between the control and pSS groups. The turquoise module indicated the highest correlation with pSS, and 252 key genes were identified. The PPI network of key genes showed that RPL9, RBX1, and RPL31 had a relatively higher degree. In addition, the key genes were mainly enriched in coronavirus disease-COVID-2019, hepatitis C, and influenza A. Fourteen feature genes were obtained using the support vector machine model, and two subtypes were identified. The genes in the two subtypes were mainly enriched in the JAK-STAT, p53, and toll-like receptor signaling pathways. The majority of the feature genes were upregulated in the pSS group, verified using the GEO datasets and RT-qPCR analysis.Conclusions: Memory B cells, gamma delta T cells, Tregs, activated dendritic cells, RPL9, RBX1, RPL31, and the feature genes possible play vital roles in the development of pSS.

Bartonella henselae masquerading as possible gamma–delta T-cell lymphoma in a paediatric patient with 22q11.2 deletion syndrome

A 14-year-old boy with 22q11.2 deletion syndrome and a right ventricular to pulmonary artery xenograft conduit presented to an Australian tertiary children’s hospital with prolonged fevers, weight loss, splenomegaly and a high proportion of gamma–delta T cells in peripheral blood and bone marrow, concerning for possible gamma–delta T-cell lymphoma. However, investigations did not reveal evidence of lymphoma or autoimmune disease. After 5 months of intermittent fever episodes and ongoing symptoms, he was found to have an extremely high Bartonella henselae titre (8192) on serological testing, with the organism also detected on blood PCR. After 6 months of oral azithromycin and rifampicin, with complete resolution of his symptoms 3 months into treatment, his blood PCR was negative and gamma–delta T cells in peripheral blood were decreasing. The B. henselae titre remained unchanged for some time, but decreased to 2048 around 1 year after treatment was started.

Significant Difference of Immune Cell Fractions and Their Correlations With Differential Expression Genes in Parkinson’s Disease

Parkinson’s disease (PD) is the second most neurodegenerative disease in the world. T cell infiltration in the central nervous system (CNS) has provided insights that the peripheral immune cells participate in the pathogenesis of PD. However, the association between the peripheral immune system and CNS remains to be elucidated. In this study, we analyzed incorporative substantia nigra (SN) expression data and blood expression data using the CIBERSORT to obtain the 22 immune cell fractions and then explored the molecular function to identify the potential key immune cell types and genes of PD. We observed that the proportions of naïve CD4 T cells, gamma delta T cells, resting natural killer (NK) cells, neutrophils in the blood, and regulatory T cells (Tregs) in the SN were significantly different between patients with PD and healthy controls (HCs). We identified p53-induced death domain protein 1 (PIDD1) as the hub gene of a PD-related module. The enrichment score of the neuron-specific gene set was significantly different between PD and HC, and genes in the neuron-related module were enriched in the biological process about mitochondria and synapses. These results suggested that the fractions of naïve CD4 T cells, gamma delta T cells, resting NK cells, and neutrophils may be used as a combined diagnostic marker in the blood, and Tregs in SN may be a potential therapeutic design target for PD.