IRF4 is required for migration of CD4+ T cells to the intestine but not for Th2 and Th17 cell maintenance

The transcription factor Interferon Regulatory Factor 4 (IRF4) is central in control of T cell activation and differentiation. Deficiency of IRF4 results in severe immune deficiency and affects maturation and function of most if not all T cell subsets. Here we use mouse infection models for Citrobacter rodentium and Strongyloides ratti to analyze the function of IRF4 in T helper (Th) 17 and Th2 cell responses, respectively. IRF4 deficient mice were impaired in the control of both pathogens, failed to mount Th17 and Th2 cell responses and showed impaired recruitment of T helper cells to the intestine, the infection site of both pathogens. Compromised intestinal migration was associated with reduced expression of the intestinal homing receptors α4β7 integrin, CCR9 and GPR15. Identification of IRF4 binding sites in the gene loci of these receptors suggests a direct control of their expression by IRF4. Competitive T cell transfer assays further demonstrated that loss of one functional Irf4 allele already affected intestinal accumulation and Th2 and Th17 cell generation, indicating that lower IRF4 levels are of disadvantage for Th2 and Th17 cell differentiation as well as their migration to the intestine. Conversion of peripheral CD4⁺ T cells from an Irf4 wildtype to an Irf4 heterozygous or from an Irf4 heterozygous to a homozygous mutant genotype after C. rodentium or S. ratti infection did not reduce their capacity to produce Th17 or Th2 cytokines and only partially affected their persistence in the intestine, revealing that IRF4 is not essential for maintenance of the Th2 and Th17 phenotype and for survival of these T helper cells in the intestine. In conclusion, we demonstrate that the expression levels of IRF4 determine Th2 and Th17 cell differentiation and their intestinal accumulation but that IRF4 expression is not crucial for Th2 and Th17 cell survival.

Cell-Autonomous Constitutive gp130 Signaling in T Cells Amplifies TH17 Cell Responses and Causes Severe Lung Inflammation

IL-6 plays a fundamental role in T cell differentiation and is strictly controlled by surface expression and shedding of IL-6R. IL-6 also acts on other cells that might affect T cell maturation. To study the impact of cell-autonomous and uncontrolled IL-6 signaling in T cells, we generated mice with a constitutively active IL-6R gp130 chain (Lgp130) expressed either in all T cells (Lgp130 × CD4Cre mice) or inducible in CD4+ T cells (Lgp130 × CD4CreERT2 mice). Lgp130 × CD4Cre mice accumulated activated T cells, including TH17 cells, in the lung, resulting in severe inflammation. Tamoxifen treatment of Lgp130 × CD4CreERT2 mice caused Lgp130 expression in 40-50% of CD4+ T cells, but mice developed lung disease only after several months. Lgp130+ CD4+ T cells were also enriched for TH17 cells; however, there was concomitant expansion of Lgp130- regulatory T cells, which likely restricted pathologic Lgp130+ T cells. In vitro, constitutive gp130 signaling in T cells enhanced but was not sufficient for TH17 cell differentiation. Augmented TH17 cell development of Lgp130+ T cells was also observed in Lgp130 × CD4CreERT2 mice infected with Staphylococcus aureus, but gp130 activation did not interfere with formation of TH1 cells against Listeria monocytogenes. Lgp130+ CD4+ T cells acquired a memory T cell phenotype and persisted in high numbers as a polyclonal T cell population in lymphoid and peripheral tissues, but we did not observe T cell lymphoma formation. In conclusion, cell-autonomous gp130 signaling alters T cell differentiation. Although gp130 signaling is not sufficient for TH17 cell differentiation, it still promotes accumulation of activated T cells in the lung that cause tissue inflammation.

Proactive care post-discharge to reduce 30 day readmissions to hospital

BACKGROUND

Healthwatch England estimated emergency readmissions have risen by 22.8% between 2012-13 and 2016-17. Some emergency readmissions could be avoided by providing patients with urgent out of hospital medical care or support. Sovereign Health Network (SHN) comprises of three GP practices, with a combined population of 38,000.

OBJECTIVE

We will decrease the number of SHN patients readmitted within 30 days of discharge from Portsmouth Hospitals Trust following a non-elective admission (excluding Emergency Department attendance) by 40-60% by July 2020.

METHODS

Four Plan, Do, Study, Act (PDSA) cycles were used to test the administrative and clinical processes. Our Advanced Nurse Practitioner reviewed all discharge summaries, added alerts to records, and proactively contacted patients either by text, telephone or home visit.

RESULTS

92 patients aged 23 days to 97 years were admitted onto the recent discharge scheme. Half of discharge summaries were received on the day of discharge, whilst 29% of discharge summaries were received more than 24 hours post-discharge, and one was received 11 days post-discharge. Following our interventions, there were 55% less than expected readmissions during the same time period.

CONCLUSION

To allow proactive interventions to be instigated in a timely manner, discharge summaries need to be received promptly. The average readmission length of stay following a non-elective admission is seven days. Our proactive interventions saved approximately 102.9 bed days, with potential savings of 1,775 bed days over a year. We feel the results from our model are promising and could be replicated by other Primary Care Networks to result in larger savings in bed days.

Pathogen-induced tissue-resident memory TH17 (TRM17) cells amplify autoimmune kidney disease

Although it is well established that microbial infections predispose to autoimmune diseases, the underlying mechanisms remain poorly understood. After infection, tissue-resident memory T (T_RM) cells persist in peripheral organs and provide immune protection against reinfection. However, whether T_RM cells participate in responses unrelated to the primary infection, such as autoimmune inflammation, is unknown. By using high-dimensional single-cell analysis, we identified CD4⁺ T_RM cells with a T_H17 signature (termed T_RM17 cells) in kidneys of patients with ANCA-associated glomerulonephritis. Experimental models demonstrated that renal T_RM17 cells were induced by pathogens infecting the kidney, such as Staphylococcus aureus, Candida albicans, and uropathogenic Escherichia coli, and persisted after the clearance of infections. Upon induction of experimental glomerulonephritis, these kidney T_RM17 cells rapidly responded to local proinflammatory cytokines by producing IL-17A and thereby exacerbate renal pathology. Thus, our data show that pathogen-induced T_RM17 cells have a previously unrecognized function in aggravating autoimmune disease.

[Waiting time for and length of physicianc's consultation define the patient-physician interaction: results of a prospective study in 478 patients with chronic viral hepatitis]

BACKGROUND

Little is known about the physician-patient interaction in hepatitis B and C.

METHODS

This study by the federal competence network hepatitis analysed the physician-patient interaction using the validated FAPI questionnaire. The questionnaire also contained questions concerning demography and disease characteristics. Of the total 1500 questionnaires sent out, 478 were returned (32 %) (20 % HBV vs. 80 % HCV).

RESULTS

The FAPI index of patients with HBV/HCV infection (3.10 +/- 0,99) was lower than that in patients with other internal medicine diseases (3.61 +/- 0.92; n = 148). Women had lower values than men (2.98 vs. 3.25; p = 0.005). Patients with active HBV infection showed higher values than those with HCV infection (3.27 vs. 2.97; p < 0.05). Patients with successfully treated hepatitis B/C had higher values than those with active disease (3.36 vs. 3.02; p = 0.004). The index was lower in patients who waited > 2 weeks for the consultation when compared to those with a shorter wait (2.92 vs. 3.31; p < 0.001) and was also lower in patients who waited > 30 min at the consultation day when compared to those with a shorter wait (2.81 vs. 3.39; p < 0.001). The index gradually increased with the consultation length (2.47 < 10 min vs. 2.79 10 - 15 min vs. 3.21 15 - 30 min vs. 3.82 > 30 min; p < 0.001). The index was higher in patients seen by gastroenterologists (3.43) when compared with general practioners (3.10), internists (3.02) and clinical settings (3.13) (p < 0.05). A good information status was associated with higher FAPI values when compared with a bad information status (3.43 vs. 2.76; p < 0.001). Fibrosis, health insurance and age were not associated with FAPI index (p > 0.2). By multivariate analysis a long consultation, a good information status, patients' patience, short waiting times, and providing contact to a patient support group were independently associated with a high index.

CONCLUSIONS

The physician-patient interaction in chronic viral hepatitis is worse than in other internal medicine diseases with problems being more pronounced in HCV infection and women when compared to men and HBV infection. Short waiting times and patients' patience ameliorated the interaction as well as the consultation length, the information status of the patient and providing contact to a patient support group. Type of health insurance did not affect either waiting times or physician-patient interaction; thus there is no hint for a two-class medicine in this part of hepatology.

ACE-Asia intercomparison of a thermal-optical method for the determination of particle-phase organic and elemental carbon

A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter samples collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter samples collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected samples from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient samples, four source samples, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke sample were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient samples and a coal fly ash sample showed moderate sensitivity to temperature program, while a carbon black sample and a sample of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.

[Particular posteromedial and posterolateral approaches for the treatment of tibial head fractures]

Tibial plateau fractures with depression of posterior aspects of the proximal tibia cause significant therapeutic problems. Posterior fractures on the medial side are mainly highly instable fracture-dislocations (Moore type I). Posterolateral fractures usually cause massive depression and destruction of the chondral surface. Surgical exposure of these fractures from anterior requires major soft tissue dissection and has a significant complication rate. However, incomplete restoration of the joint surface results in chronic postero-inferior joint subluxation, osteoarthritis and pain. We present new specific approaches for posterior fracture types avoiding large skin incisions, but allowing for atraumatic exposure, reduction and fixation. Posteromedial fracture-dislocations are exposed by a direct posteromedial skin incision and a deep incision between medial collateral ligament and posterior oblique ligament. The posteromedial pillar and the posterior flare of the proximal tibia are visualized. The inferior extent of the joint fragment can be reduced by indirect techniques or direct manipulation of the fragment. Fixation is achieved with subchondral lag screws and an anti-glide plate at the tip of the fragment. Posterolateral fractures are exposed by a transfibular approach: the skin is incised laterally, the peroneal nerve is dissected free. The fibula neck is osteotomized, the tibiofibular syndesmosis is divided and the fibula neck is reflected upwards in one layer with the meniscotibial ligament and the iliotibial tract attachment. Reflexion of the fibula head relaxes the lateral collateral ligament, allows for lateral joint opening and internal rotation of the tibia and thus exposes the posterolateral and posterior aspect of the tibial plateau. Fixation and buttressing on the posterolateral side can be achieved easily with this approach. In closure, the fibula head is fixed back with a lag screw or a tension-band system. These two exposures can be combined in bicondylar posterior fracture situations. 168 cases with tibial plateau fractures had ORIF in the authors' institution from 1988 to 1994. 26 of these patients had a total of 29 posterior exposures to treat their fractures (9 posteromedial, 12 posterolateral, 3 combined posteromedial/posterolateral and 2 posterior/anterior exposures). No specific complications occurred related to these exposures, i.e. no skin slough, no infection, no nerve palsy. The mean duration of follow-up was 4 years. Twenty-one cases healed uneventfully: 12 were excellent in Rasmussen's clinical score, 8 were good and 1 was fair. Seven patients were excellent in the radiological score, 13 good and 1 fair. Five of the 26 cases had revision surgery: 3 patients developed valgus or retrocurvatum deformity and were successfully treated by an osteotomy. They obtained a good result at follow-up. Two fractures in elderly patients were revised to an endoprosthesis.

Differential activation of microglia and astrocytes following trimethyl tin-induced neurodegeneration

We have investigated the response of astrocytes and microglia to trimethyl tin intoxication in the septum, hippocampus, olfactory bulb, and pyriform cortex of the rat. Microglia were studied qualitatively using lectin histochemistry, and astrocytes were examined both qualitatively with immunohistochemistry, and quantitatively using an immunoassay for glial fibrillary acidic protein. Our results show that activated microglia first appeared 2 days after trimethyl tin intoxication in the lateral septum and hippocampus. Four days after trimethyl tin intoxication, the same regions revealed a most intense microglial reaction characterized by microglial hypertrophy and the formation of phagocytic clusters. By day 7, microglial activation in the septum and hippocampus had lessened, suggesting that the cells were reverting to the resting phenotype. The microglial response in the pyriform cortex and olfactory bulb, while being later in onset than in the septum and hippocampus, showed a similar progression of microglial changes reaching maximal intensity 7 days after trimethyl tin intoxication. Significant increases in the expression of glial fibrillary acidic protein were observed in all regions examined and typically occurred after microglial activation was already underway. We conclude that microglial and astroglial reactions which occur in response to trimethyl tin-induced neuronal necrosis are separated in time, with microglial activation preceding astrogliosis. In addition, our study stresses the importance of microglia as an endogenous source of CNS macrophages, and illustrates the merit of histochemical analysis with microglial markers for the early delineation of neurotoxicant-induced brain damage.

Drug prescribing for TPN patients at a teaching hospital serving a developing community

Drug prescribing for TPN patients at Ga-Rankuwa Hospital was investigated as part of a larger retrospective survey of TPN products and practices. The medical records of 45 patients who received parenteral nutrition over the period April-August 1985 were examined. Relevant information was transcribed onto survey forms, classified and analysed. The major defined complaints were gastrointestinal (50%) and perinatal (34.5%). Twelve patients had more than one major complaint. Seventy-three per cent of the patients were admitted to paediatric wards and over 24% to (adult) surgical wards. There was one medical patient in the group. The only drug categories that were prescribed in more than 10% of cases were antimicrobial agents (64.9%) and analgesics (10.4%). The most frequently used individual drugs were gentamicin (17.5%), penicillin G (14.3%), piperacillin (17%) and aminophylline (11%). The implications of this pattern of drug use for TPN patient monitoring are discussed.