Characterization of putative regulatory isoforms of porcine tumor necrosis factor receptor 2 in endothelial cells

Tumor necrosis factor α (TNFα) and its receptors contribute to rejection of transplanted cells and organs. To elucidate how TNFα affects xenograft rejection, we previously cloned the cDNA of pig TNF-receptor 2 (pTNFR2) and found four isoforms: one comprising the full receptor with four cysteine-rich domains (CRD), a shorter variant (pTNFR2ΔE7-10) encoding for a soluble isoform, another lacking exon 4 (pTNFR2ΔE4) displaying only 3 CRD and poor ligand binding, and the smallest one generated by the two alternative splicings. All isoforms contained the pre-ligand assembly domain (PLAD) responsible for receptor trimerization. We now investigated their roles by structural, expression, and subcellular localization studies. Structural in silico analyses identified four amino acids potentially involved in TNFα binding and lacking in pTNFR2ΔE4. Quantitative RT-PCR determined regulated expression affecting the two pTNFR2 alternative splicings in cytokine-stimulated porcine aortic endothelial cells (PAEC). Particularly, human IL-1α and TNFα produced a strong mRNA upregulation of all isoforms, being the full receptor the predominant one. However, expression of pTNFR2 on PAEC did not correlate with mRNA and decreased after 24-hour exposure to IL-1α or TNFα. Notably, confocal microscopy confirmed the presence of pTNFR2 inside and on the plasma membrane, whereas pTNFR2ΔE4 located only intracellularly. Most interestingly, FRET analyses showed that membrane-bound isoforms pTNFR2 and pTNFR2ΔE4 colocalized intracellularly and associated through the PLAD. Our data show that pTNFR2ΔE4 bind and may retain the full receptor intracellularly. This mechanism has not been described in other species and represents a particularity that may affect the pathophysiology of pig xenografts.     

Onset of fulminant type 1 diabetes mellitus following hypophysitis after discontinuation of combined immunotherapy. A case report

Diabetes is a rare, but potentially life-threatening, adverse event of immune checkpoint inhibitors that requires prompt recognition and treatment. It usually occurs in the first 3 months of treatment and is typically related to programmed cell death-1 antibodies, alone or in combined therapy. It has rarely been described developing after immunotherapy cessation. We present a 51-year-old man with metastatic melanoma, who developed acute-onset diabetes 52 days after combined immunotherapy cessation with nivolumab and ipilimumab, and 25.6 months after receiving the first dose. He presented with acute hyperglycemic symptoms, ketosis, complete insulin depletion and negative autoimmunity, fulfilling the criteria of fulminant type 1 diabetes. The patient had previously developed hypophysitis with isolated adrenocorticotropic hormone deficiency during immunotherapy. We describe a case of late-onset fulminant type 1 diabetes developing after immunotherapy cessation. Patient education and active follow up after immunotherapy discontinuation are crucial to warrant a timely intervention.     

Impact of in vitro evolution on antigenic diversity of Mycobacterium bovis bacillus Calmette-Guerin (BCG)

Mycobacterium bovis bacillus Calmette-Guerin (BCG), the only vaccine currently used against tuberculosis, is an attenuated derivative of M. bovis that has been propagated in vitro for more than 40 years. We have previously reported that the experimentally-verified human T cell epitopes of the M. tuberculosis complex (MTBC) are the most conserved elements of the genome; whether immune recognition is the force driving the conservation of epitopes in the MTBC is unknown. Therefore, we sequenced the genomes of 12 BCG strains to determine whether T cell epitopes were under selection pressure during BCG in vitro evolution. We constructed a genome-wide phylogeny and refined the previously-determined BCG phylogeny. Notably, we identified a new cluster between BCG Japan and BCG Russia, and repositioned the relationships of several strains within the lineage. We also compared the sequence diversity of 1530 experimentally verified human T cell epitopes in the BCG vaccines with those in the MTBC. We found 23% of the known T cell epitopes are absent, and that the majority (82%) of the absent epitopes in BCG are contained in 6 proteins encoded in 2 regions of difference (RD) unique to BCG strains. We also found that T cell epitope sequences in BCG are more conserved than non-epitope sequences in the same gene. Finally, we find evidence that epitope sequence variation in BCG potentially affects human T cell recognition. These findings provide new insight into sequence variation in a slow-growing bacterium closely related to the MTBC that has been subjected to prolonged passage outside of a mammalian host, and indicate little difference in the extent of variation in vivo and in vitro.     

The Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) Questionnaire: item reduction and further validation

Purpose

The Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) Questionnaire is a patient and parent-completed disease-specific instrument used in Hunter syndrome (mucopolysaccharidosis II), a rare paediatric progressive multi-systemic lysosomal storage disease. The objective of this study was to shorten the number of items of the Questionnaire to reduce response burden while maintaining its content validity.

Methods

Data collected in a clinical trial were used. An iterative process helped identifying redundant or low performing items based on content validity and psychometric properties. Validation on the retained items was assessed using patients and parent’s responses in terms of reliability, validity and responsiveness.

Results

The HS-FOCUS was completed by 49 patients and 84 parents. Items were mainly removed owing to high floor effects, high inter-item correlations (>0.80) or inadequate content. The shortened patient and parent versions (18 and 21 items) each contained five function domains. Internal consistency and test–retest reliability were >0.70 for most domains, except Breathing and School/work. Concurrent validity was demonstrated by significant correlations (>0.30) with similar concepts of previously validated measures. Significant differences were found in all domain scores across levels of disability.

Conclusions

The shortened HS-FOCUS is a reliable, valid and responsive measure, where burden in answering the Questionnaire was reduced without compromising its validity.     

Immunofluorescence analysis of sensory nerve endings in the interosseous membrane of the forearm

The human interosseous membrane (IOM) is a fundamental stabilizer during forearm rotation. To investigate the dynamic aspects of forearm stability, we analyzed sensory nerve endings in the IOM. The distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC) and the proximal oblique cord (POC) were dissected from 11 human cadaver forearms. Sensory nerve endings were analyzed at two levels per specimen as total cell amount/mm² after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4′,6-diamidino-2-phenylindole on an Apotome microscope, according to Freeman and Wyke’s classification. Sensory nerve endings were significantly more commonly found to be equally distributed throughout the structures, rather than being epifascicular, interstitial, or close to the insertion into bone (P ≤ 0.001, respectively). Free nerve endings were the predominant mechanoreceptor in all six structures, with highest density in the DOB, followed by the POC (P ≤ 0.0001, respectively). The DOB had the highest density of Pacini corpuscles. The DOAC and CB had the lowest amounts of sensory innervation. The high density of sensory corpuscles in the DOB, PAB and POC indicate that proprioceptive control of the compressive and directional muscular forces acting on the distal and proximal radioulnar joints is monitored by the DOB, PAB and POC, respectively, due to their closed proximity to both joints, whereas the central parts of the IOM act as structures of passive restraint.     

Assessment of PCR status of vector-borne pathogens in dogs presenting arrhythmias

Arrhythmias are frequent and can be caused by many diseases. Vector-borne diseases are increasing in importance as a cause of arrhythmias in veterinary medicine. The objective of the study was to evaluate dogs presenting arrhythmias of any aetiology and to assess the influence of polymerase chain reaction (PCR) status for vector-borne pathogens in the Mediterranean area of Spain. A total of 120 dogs presenting arrhythmias were prospectively selected, and PCR for several vector-borne pathogens (Leishmania infantum, Ehrlichia/Anaplasma spp., Babesia spp., Rickettsia spp., Mycoplasma spp., Hepatozoon canis and Bartonella spp.) were analysed in blood samples. Twenty-four (20 %) dogs had positive results for PCR. Found pathogens were Ehrlichia/Anaplasma spp. (n?=?10, 8.3 %), Babesia spp. (n?=?7, 5.8 %), Rickettsia spp. (n?=?5, 4.2 %), Leishmania spp. (n?=?4, 3.3 %), Mycoplasma spp. (n?=?4, 3.3 %), and H. canis (n?=?1, 0.8 %). No significant differences were found in relation to PCR status and type or cause of the arrhythmia. Although there is a clear association between some infectious diseases and cardiac diseases, this study could not find evidence of the role of infectious agents as triggers for arrhythmias in dogs. More studies are needed to further explore this association.     

Lung function of preterm infants before and after viral infections

Our aim was to determine whether viral lower respiratory tract infections (LRTIs) adversely affect prematurely born infants’ lung function at follow up. Seventy infants, median gestational age 34 (range, 24–35)?weeks were prospectively followed; 32 had an RSV (n?=?14) or another respiratory viral (n?=?18) LRTI (viral LRTI group) and 38 had no LRTI (no LRTI group). Six of the viral LRTI and five of the no LRTI group had been hospitalised. Nasopharyngeal aspirates (NPAs) obtained whenever the infants had an LRTI. Lung function (functional residual capacity [FRC_He], compliance [Crs] and resistance [Rrs] of the respiratory system) was measured at 36 weeks postmenstrual age (PMA) and 1 year corrected. At 1 year, lung volume (FRCpleth) and airways resistance (Raw) were also assessed. There were no significant differences in the lung function of the two groups at 36 weeks PMA but at 1 year, the viral LRTI compared to the no LRTI group had a higher mean Raw (23 versus 17 cm H₂O/l/s, p?=?0.0068), the differences remained significant after adjustment. Conclusion: These results suggest viral LRTIs, regardless of whether hospitalisation is required, adversely affect prematurely born infants’ airway resistance at follow up.