Infliximab desensitization in patients with inflammatory bowel diseases: a safe therapeutic alternative

BACKGROUND

Hypersensitivity reactions (HSR) to the administration of infliximab (IFX) in Inflammatory Bowel Diseases (IBD) patients are not rare and usually lead to drug discontinuation. We report data on safety and effectiveness of desensitization to IFX in patients with previous HSR.

METHODS

We conducted a retrospective monocentric observational study. Patients for whom a desensitization protocol to IFX was realized after a previous HSR were included. Anti-drug antibodies (ADA) and IFX trough levels at both inclusion and six months after desensitization were collected. Clinical outcomes, including recurrence of HSR were evaluated.

RESULTS

From 2005 to 2020, 27 patients (Crohn's Disease: 26 (96%) were included). Desensitization after HSR was performed after a median time of 10.4 months (2.9-33.1). Nineteen (70%) patients received immunosuppressants at time of desensitization. Eight (30%) patients presented HSR at first (n = 2), second (n = 4) or third (n = 2) IFX perfusion after desensitization. None led to intensive care unit transfer or death. Thirteen (48%) had clinical response at 6 months and 8 (29%) were still under IFX treatment two years after desensitization. IFX trough levels and ADA were available for 14 patients at time of desensitization. Most patients (12 out of 14) had ADA at a high level. At 6 months, among the 7 patients with long term response to IFX, 4 presented a decrease of ADA titers and 2 had a significant trough level of IFX.

CONCLUSION

IFX desensitization in patients with IBD is a safe therapeutic alternative and represents a potential option for patients refractory to multiple biologics.What is already known? Hypersensitivity reactions to the administration of infliximab is frequent. Occurrence of hypersensitivity reaction, either immediate or delayed, usually leads to permanent drug discontinuation.What is new here? Infliximab desensitization is well tolerated with no hypersensitivity reaction recurrence in 70% of patients. Clinical success at 6 months was of 48% and around a third of patients remained under infliximab therapy two years after desensitization. Antidrug antibodies decreased and infliximab trough levels increased in these patients showing the impact of desensitization on immunogenicity.How can this study help patient care? Infliximab desensitization represents a potential option for patients refractory to multiple biologics who presented hypersensitivity reaction to the drug.

Autologous organoid co-culture model reveals T cell-driven epithelial cell death in Crohn's Disease

Lympho-epithelial interactions between intestinal T resident memory cells (Trm) and the epithelium have been associated with inflammatory bowel disease (IBD) activity. We developed ex vivo autologous organoid-mucosal T cell cocultures to functionally assess lymphoepithelial interactions in Crohn's Disease (CD) patients compared to controls. We demonstrate the direct epithelial cell death induced by autologous mucosal T cells in CD patients but not in controls. These findings were positively correlated with T cell infiltration of the organoids. This potential was inhibited by limiting lympho-epithelial interactions through CD103 and NKG2D blocking antibodies. These data directly demonstrate for the first time the direct deleterious effect of mucosal T cells on the epithelium of CD patients. Such ex-vivo models are promising techniques to unravel the pathophysiology of these diseases and the potential mode of action of current and future therapies.

Kidney function monitoring in inflammatory bowel disease: The MONITORED consensus

BACKGROUND AND AIMS

Patients with inflammatory bowel diseases (IBD) are exposed to drug-related nephrotoxicity and kidney-related extra-intestinal manifestations (EIMs). Patients should be monitored but guidance is lacking in current international recommendations. The objective of the Kidney Function Monitoring in Inflammatory Bowel Disease (MONITORED) initiative was to achieve an expert consensus about monitoring kidney function in IBD.

METHODS

A literature review was first conducted. Then, an expert consensus meeting, involving 28 attendees representing French-speaking gastroenterologists and nephrologists, was held as part of an academic initiative on May 28, 2021. An anonymous Delphi process was used to discuss and vote on statements. Agreement was defined as at least 75% of participants voting for any one statement.

RESULTS

Experts reached consensus on 11 criteria for referral to the nephrologist. Concerning kidney function monitoring, participants unanimously validated the use of serum creatinine with estimation of the glomerular filtration rate via the MDRD or CKD-EPI equations. A blood ionogram and a urine sample with measurement of a protein-to-creatinine ratio were also broadly agreed validated. Experts recommended performing this monitoring at IBD diagnosis, prior introducing a new treatment, and annually for EIMs screening and evaluation of treatment tolerance. An evaluation 3 months after starting mesalamine and then every 6 months was felt necessary, while for biologics an annually monitoring was deemed sufficient.

CONCLUSION

The MONITORED consensus proposed guidelines on how to monitor kidney function in IBD. These recommendations should be considered in clinical practice to preserve kidney function and ensure the best approach to our patients.

[Sleeping Sickness: A Cause of False Positive HIV Rapid Diagnostic Tests]

Approaching the mechanisms related to false positives HIV rapid diagnostic tests (RDT) in patients with sleeping sickness may help to improve the accuracy of screening for HIV infection in areas endemic for Human African trypanosomiasis (HAT).We report on a patient from Congo who was managed like an AIDS-associated meningoencephalitis, based on a false positive HIV RDT at admission, and eventually received a diagnosis of sleeping sickness. A further retrospective cohort study performed in patients with HAT shows that most of positive HIV RDT obtained prior to treatment for sleeping sickness are false positives. We found that half of them were cleared at the end of treatment course, suggesting an early clearance of some antibodies involved in cross-reactivity.A substantial clearance of HIV RDT false positives occurs during therapy for HAT. In areas where Elisa HIV tests are not readily available, repeating the HIV RDT at the end of therapy may help to identify roughly half of false positives.

Nascent teichoic acids insertion into the cell wall directs the localization and activity of the major pneumococcal autolysin LytA

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Peptidoglycan which sustains bacterial growth is targeted by b-lactam antibiotics.

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Spread of antibiotic resistance requires the development of new antibacterial drugs.

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The cell wall of Gram-positive bacteria carries teichoic acids and virulence factors.

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Function and surface localization of virulence factors are regulated by teichoic acids.

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Anti-bacterial strategy should target the localization of surface virulence factors.

The bacterial cell wall is in part composed of the peptidoglycan (PG) layer that maintains the cell shape and sustains the basic cellular processes of growth and division. The cell wall of Gram-positive bacteria also carries teichoic acids (TAs). In this work, we investigated how TAs contribute to the structuration of the PG network through the modulation of PG hydrolytic enzymes in the context of the Gram-positive Streptococcus pneumoniae bacterium. Pneumococcal TAs are decorated by phosphorylcholine residues which serve as anchors for the Choline-Binding Proteins, some of them acting as PG hydrolases, like the major autolysin LytA. Their binding is non covalent and reversible, a property that allows easy manipulation of the system.

In this work, we show that the release of LytA occurs independently from its amidase activity. Furthermore, LytA fused to GFP was expressed in pneumococcal cells and showed different localization patterns according to the growth phase. Importantly, we demonstrate that TAs modulate the enzymatic activity of LytA since a low level of TAs present at the cell surface triggers LytA sensitivity in growing pneumococcal cells. We previously developed a method to label nascent TAs in live cells revealing that the insertion of TAs into the cell wall occurs at the mid-cell. In conclusion, we demonstrate that nascent TAs inserted in the cell wall at the division site are the specific receptors of LytA, tuning in this way the positioning of LytA at the appropriate place at the cell surface.

Specific and spatial labeling of choline-containing teichoic acids in Streptococcus pneumoniae by click chemistry

Propargyl-choline was efficiently incorporated into teichoic acid (TA) polymers on the surface of Streptococcus pneumoniae. The introduction of a fluorophore by click chemistry enabled sufficient labeling of the pneumococcus, as well as its specific detection when mixed with other bacterial species. The labeling is localized at the septal site, suggesting a similar location of the TA and peptidoglycan (PG) synthetic machineries. This method is a unique opportunity to improve our understanding of the spatial location of pneumococcal TA biosynthesis.

Autocatalytic association of proteins by covalent bond formation: a Bio Molecular Welding toolbox derived from a bacterial adhesin

Unusual intramolecular cross-links present in adhesins from Gram-positive bacteria have been used to develop a generic process amenable to biotechnology applications. Based on the crystal structure of RrgA, the Streptococcus pneumoniae pilus adhesin, we provide evidence that two engineered protein fragments retain their ability to associate covalently with high specificity, in vivo and in vitro, once isolated from the parent protein. We determined the optimal conditions for the assembly of the complex and we solved its crystal structure at 2 Å. Furthermore, we demonstrate biotechnological applications related to antibody production, nanoassembly and cell-surface labeling based on this process we named Bio Molecular Welding.