Upregulation of type 1 conventional dendritic cells implicates antigen cross-presentation in multisystem inflammatory syndrome.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is an acute, febrile, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated syndrome, often with cardiohemodynamic dysfunction. Insight into mechanism of disease is still incomplete. OBJECTIVE: Our objective was to analyze immunologic features of MIS-C patients compared to febrile controls (FC). METHODS: MIS-C patients were defined by narrow criteria, including having evidence of cardiohemodynamic involvement and no macrophage activation syndrome. Samples were collected from 8 completely treatment-naive patients with MIS-C (SARS-CoV-2 serology positive), 3 patients with unclassified MIS-C-like disease (serology negative), 14 FC, and 5 MIS-C recovery (RCV). Three healthy controls (HCs) were used for comparisons of normal range. Using spectral flow cytometry, we assessed 36 parameters in antigen-presenting cells (APCs) and 29 in T cells. We used biaxial analysis and uniform manifold approximation and projection (UMAP). RESULTS: Significant elevations in cytokines including CXCL9, M-CSF, and IL-27 were found in MIS-C compared to FC. Classic monocytes and type 2 dendritic cells (DCs) were downregulated (decreased CD86, HLA-DR) versus HCs; however, type 1 DCs (CD11c+CD141+CLEC9A+) were highly activated in MIS-C patients versus FC, expressing higher levels of CD86, CD275, and atypical conventional DC markers such as CD64, CD115, and CX3CR1. CD169 and CD38 were upregulated in multiple monocyte subtypes. CD56dim/CD57-/KLRGhi/CD161+/CD38- natural killer (NK) cells were a unique subset in MIS-C versus FC without macrophage activation syndrome. CONCLUSION: Orchestrated by complex cytokine signaling, type 1 DC activation and NK dysregulation are key features in the pathophysiology of MIS-C. NK cell findings may suggest a relationship with macrophage activation syndrome, while type 1 DC upregulation implies a role for antigen cross-presentation.

The effect of feeding enrichment upon reported working ability and behavior of kenneled working dogs.

It is widely recommended that kenneled dogs are provided with environmental enrichment such as toys or feeding devices. However, the adoption of enrichment for military working dogs is impeded by a widespread belief that it reduces their motivation to work. Handlers of 22 working German Shepherd dogs were asked to rate their dogs on 11 attributes pertaining to working ability, related behavioral traits, and health. Eight of the dogs were then provided with daily feeding enrichment for 4 months, while the remainder were given equivalent human attention. The same 11 traits were scored again following the enrichment period: 10 changed little over the period while handlers' reports of their dogs' Ability to learn from being rewarded increased significantly. Changes for all attributes were virtually identical in enriched and control dogs. We conclude that if correctly managed, feeding enrichment can be introduced to kenneled working dogs without any reported detrimental effects upon working ability, health, or behavior.

Behavioural and glucocorticoid responses of dogs (Canis familiaris) to kennelling: Investigating mitigation of stress by prior habituation.

We have explored the validity of urinary cortisol/creatinine ratios (C/C) and behavioural measures as indicators of acute psychological stress in the domestic dog, by monitoring 1 year old male Labrador Retrievers (N=31) prior to and following their introduction to novel kennels in a training establishment. Baseline early morning urine samples were taken in the dogs' original homes and then urine samples and remote recordings of behaviour were taken for ten consecutive days after transfer to the kennels. The impact of this potential stressor was manipulated by previously habituating half of the subjects to confinement in a kennel. We hypothesised that stress levels would increase upon introduction to the training establishment, but that the response would be mitigated by kennel habituation. C/C increased in all dogs when they entered the training establishment, this increase was significantly higher in the non-habituated group, and in this group C/C remained above baseline even 12 weeks after transfer. Despite the homogeneity of the subjects, the behaviour measured showed very little correlation to the C/C ratios, and the changes in behaviour that were observed, such as decreases in whining and time spent at the front of the kennel, could equally be attributed to dogs learning the most effective strategies for gaining human attention in the kennels as to attenuation of stress. We conclude that urinary C/C is a valuable indicator of acute stress and hence welfare status in dogs, but that behavioural measures need to be interpreted with caution due to individuality in coping strategies.