Combination of Synovial Fluid IL-4 and Polymorphonuclear Cell Percentage Improves the Diagnostic Accuracy of Chronic Periprosthetic Joint Infection

Background: Synovial fluid biomarkers have been confirmed with promising diagnostic value for chronic periprosthetic joint infection (PJI), even there was still no “gold standard”. Interleukin-4 (IL-4) and polymorphonuclear cells (neutrophil) count in synovial fluid play a crucial role in mediating local inflammation of bacterial infections and therefore could be valuable biomarkers for PJI. Methods: The purpose of this study was to investigate the diagnostic capacity of synovial fluid IL4 (SF-IL4) and polymorphonuclear cell percentage(SF-PMN%) for chronic PJI. According to the 2013 Musculoskeletal Infections Society(MSIS 2013) criteria, chronic PJI is defined as occurred more than 6 weeks after the primary arthroplasty. A total of 110 patients who scheduled to undergo revision arthroplasty from January 2019 to October 2020 were enrolled. 11 patients were eliminated by exclusion criteria. 43 of 99 patients were classified as infected and 56 as not infected. In all patients, SF-IL4 and SF-PMN% were measured in synovial fluid, serum CRP, ESR levels were measured preoperatively. The area under the curve(AUC) for each biomarker was analyzed, the diagnostic value and optimal cutoff values were calculated. Results: The demographic data was not statistically different. The SF-IL4 and SF-PMN% showed a great diagnostic accuracy of chronic PJI from aseptic failure patients with AUC of 0.97(95% confidence interval (CI), 0.92-0.99) and 0.89(95%CI, 0.82-0.95) separately, which was higher than the serum ESR (0.72), and serum CRP (0.83). We set 1.7 pg/mL and 75% as the optimal cut-off values of SF-IL4 and SF-PMN% individually. Combination of SF-IL4 and SF-PMN% improved the diagnostic ability for chronic PJI with a specificity of 97.0%, and 96.0% accuracy.Conclusion: Synovial fluid IL-4 was a valuable biomarker for chronic PJI detection. Combination of SF-IL4 and SF-PMN% provided higher specificity and accuracy when met the cut-off values of 1.7 pg/mL and 75% simultaneously.

Influenza hemagglutinin-specific IgA Fc-effector functionality is restricted to stalk epitopes

In this study, we utilized a panel of human immunoglobulin (Ig) IgA monoclonal antibodies isolated from the plasmablasts of eight donors after 2014/2015 influenza virus vaccination (Fluarix) to study the binding and functional specificities of this isotype. In this cohort, isolated IgA monoclonal antibodies were primarily elicited against the hemagglutinin protein of the H1N1 component of the vaccine. To compare effector functionalities, an H1-specific subset of antibodies targeting distinct epitopes were expressed as monomeric, dimeric, or secretory IgA, as well as in an IgG1 backbone. When expressed with an IgG Fc domain, all antibodies elicited Fc-effector activity in a primary polymorphonuclear cell-based assay which differs from previous observations that found only stalk-specific antibodies activate the low-affinity FcγRIIIa. However, when expressed with IgA Fc domains, only antibodies targeting the stalk domain showed Fc-effector activity in line with these previous findings. To identify the cause of this discrepancy, we then confirmed that IgG signaling through the high-affinity FcγI receptor was not restricted to stalk epitopes. Since no corresponding high-affinity Fcα receptor exists, the IgA repertoire may therefore be limited to stalk-specific epitopes in the context of Fc receptor signaling.

Pathological Studies of Mecistocirrus digitatus Infection in Naturally Infested Mithun and Phere (Cross Bred of Mithun)

In histopathological study, Lung was emphysematous, showed pronounced interstitial pneumonia followed by severe thickening of alveolar septa and bronchial wall, haemorrhages with connective tissue proliferation and infiltration of leucocytes around the bronchial wall. Bulla formation was also evident in some places. Liver showed mild haemorrhages of hepatocytes and congestion in sinusoidal space. In abomasum, adult parasites were embedded in mucousa and sectioning of adult parasites were seen with full of eggs. In large intestine, there was necrosis and degeneration of colonic villi and lost of normal architecture. There was also evidence of hyperactivity of acinar cells, fibrous tissue proliferation with polymorphonuclear cell infiltration. An apical tip shows degenerative changes, adhesion with mild fibrous tissue proliferation. In small intestine, there was congestion, oedema with thickening of sub mucousa as well as erosion of intestinal villi in certain areas, adhesion and fibrous tissue proliferation. In spleen, there was depletion of spleenic venule, congestion of spleenic pulp, haemorrhages surrounding the spleenic venule.