Haploidentical CD3+ TCR αβ/CD19+-depleted HSCT for MHC class II deficiency and persistent SARS-CoV-2 pneumonitis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to coronavirus disease 2019 (COVID-19), which can range from a mild illness to a severe phenotype characterized by acute respiratory distress needing mechanical ventilation. Children with combined immunodeficiencies might be unable to mount a sufficient cellular and humoral immune response against COVID-19 and have persistent disease.

Objective

Our aim was to describe a child with combined immunodeficiency and a favorable post-hematopoietic stem cell transplant (HSCT) course following a haploidentical HSCT in the presence of persistent SARS-CoV-2 infection.

Methods

A 13-month-old girl with MHC class II deficiency developed persistent pre-HSCT SARS-CoV-2 infection. Faced with a significant challenge of balancing the risk of progressive infection due to an incompetent immune system with the danger of inflammatory pneumonitis peri-immune reconstitution after HSCT, the patient's physicians performed a maternal (with a recent history of COVID-19 infection) haploidentical HSCT. The patient received regdanvimab (after stem cell infusion) and remdesivir (before and after stem cell infusion).

Results

The patient exhibited a gradual increase in her cycle threshold values, implying a reduction in viral RNA with concomitant expansion in the CD3 lymphocyte subset and clinical and radiologic improvement.

Conclusions

Combination of adoptive transfer of maternal CD45RO⁺ memory addback T lymphocytes after haploidentical HSCT and use of regdanvimab (a SARS-CoV-2-neutralizing mAb) and remdesivir may have led to the successful outcome in our patient with severe immunodeficiency after she had undergone HSCT. This case highlights the role of novel antiviral strategies (mAbs and CD45RO⁺ memory T lymphocytes) in contributing to viral clearance in a challenging clinical scenario.

P011 Sharing is caring: a regional service development project exploring secondary immunosuppression in children

Background/Aims 

The range of approved immunosuppressive and immunomodulatory (IM) agents has grown considerably with an increasing list of indications across paediatric specialties. At present, there is limited evidence supporting best practice for prescribing and monitoring of IM agents in children and young people (CYP). We present a staged service development project exploring cross-specialty prescribing and monitoring of IM agents at a tertiary children’s hospital (Great North Children’s Hospital, GNCH) and data sharing with local hospitals across northeast England.

Methods 

In Phase 1, we searched pharmacy databases and surveyed specialty teams in GNCH to identify clinicians regularly prescribing IM agents to CYP over a twelve-month period. Phase 2 was a cross-specialty retrospective case-notes review of prescribing, monitoring and infection surveillance in a representative sample of CYP on IM agents. Phase 3 explored information sharing with six other hospitals in the region and acute presentations to these sites involving CYP on IM agents.

Results 

Phase 1 identified 9 paediatric and 2 adult specialties prescribing IM agents to 416 CYP. 32 discrete IM therapies were prescribed with significant between-specialty overlap in drugs prescribed but a wide range of prescribing and monitoring practices. Phase 2 assessed 77 CYP on IM agents in detail - 57% were prescribed >1 IM agent, 100% had FBC measured at least once (range once only to weekly), 18% developed lymphopenia at least once and 40% were prescribed prophylactic antibiotics. Previous varicella exposure had been assessed in 70%. Phase 3 data are summarised in Table 1. P011 Table 1:Information sharing and acute presentations to regional hospitals local to immunosuppressed patientsTotal number of patients141Mean age in years (range)11 (2 - 17)NDiagnosisJIA without uveitis108JIA with uveitis9Uveitis alone8Systemic JIA4Period fever4Behçet’s disease2Juvenile dermatomyositis2Scleroderma1Juvenile systemic lupus erythematosus1Mixed connective tissue disease1Granulomatosis with polyangiitis1Immunosuppressive or immunomodulatory agent usedAdalimumab65Methotrexate42Tocilizumab22Mycophenolate mofetil10Etanercept10Infliximab5Sulfasalazine5Prednisolone4Abatacept4Leflunomide4Canakinumab2Colchicine2Anakinra2Rituximab2Cyclophosphamide1Number of immunosuppressive or immunomodulatory agents per patient3 agents52 agents441 agent92Number of acute presentations by diagnosis or presenting complaint (n = 19)Fever4Chickenpox4Viral upper respiratory tract infection2Joint pain2Abdominal pain2Rash2Eye infection1Tonsilitis1Wheeze1Yes (%)No (%)Named local consultant (n = 129)3763Correct diagnosis recorded locally (n = 130)8020Correct immunosuppressive or immunomodulatory agent recorded locally (n = 130)5050Open access for febrile illness (n = 116)4159Reviewed in past 2 years for acute illness (n = 109)1783Note: presented numbers for immunosuppressive or immunomodulatory agents are not mutually exclusive. JIA, juvenile idiopathic arthritis

Conclusion 

IM agents are central to modern paediatric clinical care across a wide range of diseases. This staged project identified significant variation in IM prescribing and monitoring practice between specialties at GNCH. Communication between specialty and local teams is inadequate. Particular areas of concern include limited diagnostic, blood monitoring and medication information sharing and limited local information governing management of intercurrent illness and vaccination. Although different disease processes can necessitate different advice and prescribing practices, sharing examples of good practice will minimise unnecessary variation. We propose the development of a regional immunosuppression working group to improve quality and safety across our region.

Disclosure 

J.L. Bennett: None. C. Tsilifis: None. A. Flinn: None. T. Altmann: None. N. Jansen: None. H. Tumelty: None. K. Aitken: None. S. Bhopal: None. E. Harrison: None. S. Ravenscroft: None. E. Sen: None. E. Williams: None. T. Flood: None. S. Sampath: None. A. Battersby: None. F. McErlane: None.

Allergic reaction to peanuts: can we predict reaction severity in the wild?

Peanut allergy (PNA) is the main cause of food-induced anaphylaxis. Severe allergic reactions are more likely to occur in older patients and those with underlying asthma. Skin prick testing and measuring serum-specific IgE and recombinant peanut protein levels have been shown to be useful in the diagnosis of PNA and prediction of reactivity, but these tests are less consistent and reliable in terms of predicting the severity of reactions. Recent research has examined the role of biological mediators in allergic reactions such as platelet-activating factor. These may provide a future tool in predicting those at risk of severe reactions. Currently, there are no parameters that can predict with certainty those at risk of anaphylaxis, and management of PNA should continue to focus on patient and family education.

Children in hospital in Ireland--what do they eat and what do they weigh: a cross-sectional study

Background

Overweight and obesity is a growing problem in Ireland. Many parents are unaware when their child is overweight or obese. Our objectives were to examine parents’ perceptions of a healthy diet and their children’s BMI; and to evaluate the food offered to children in our paediatric in-patient unit.

Findings

A retrospective questionnaire was distributed to 95 patients and their families admitted over one month. Seventy-eight had BMI values calculated (42 males, 36 females). Twenty-one children (26.9%) were overweight/obese: 14/21 parents (66.7%) thought their child had a normal weight. Sixty percent of children served dinner in the hospital were given fried potatoes. Four had fruit/vegetables. Forty-six parents brought food into hospital, of these 14 brought purchased food.

Conclusions

This study highlights the problem of child obesity in Ireland and parental underestimation of this problem. The nutritional value of food served to children in hospital needs to be improved and hospital admissions used as opportunities to promote healthy eating habits.

Quinazoline antifolates inhibiting thymidylate synthase: 4-thio-substituted analogues

We report the synthesis of four new 4-thio-5,8-dideazafolic acid analogues and a 4-(methylthio) analogue structurally related to the thymidylate synthase (TS) inhibitor N10-propargyl-5,8-dideazafolic acid. Three N10-propargyl-4-thio-5,8-dideazafolic acid analogues had C2 amino, hydrogen, and methyl substituents. A 4-thio and a 4-(methylthio) compound each with hydrogen at C2 and ethyl at N10 were also synthesized. In general, the synthetic route involved thionation of the appropriate 4-oxoquinazoline; the sulfur thus introduced was then protected by methylation. Further protection with a pivaloyl group was required for the quinazoline bearing a 2-amino substituent. The protected quinazolines were treated with N-bromosuccinimide and the resulting 6-(bromomethyl) compounds were then coupled to the appropriate N-monoalkylated diethyl N-(4-aminobenzoyl)-L-glutamate in N,N-dimethylacetamide with calcium carbonate as base. The 4-thio-5,8-dideazafolic acids were obtained by removal of the methylthio group with sodium hydrosulfide, followed by deprotection of the carboxyl groups with cold dilute alkali. For the compound containing a pivaloyl protecting group, hot dilute alkali was used. To obtain the 5,8-dideazafolic acid containing a 4-(methylthio) substituent, the corresponding diester was treated with lithium hydroxide which selectively deprotected the carboxyl groups. The five compounds were tested as inhibitors of L1210 TS. It was found that replacement of the 4-oxygen of the quinazoline moiety by sulfur did not alter the TS inhibition. However, the introduction of a methylthio substituent at position 4 severely impaired TS inhibition. All 4-thio compounds were less cytotoxic to L1210 cells in culture than their 4-oxo counterparts.

Quinazoline antifolates inhibiting thymidylate synthase: 2-desamino derivatives with enhanced solubility and potency

The poor solubility of the thymidylate synthase (TS) inhibiting antifolate 10-propargyl-5,8-dideazafolic acid has posed problems for its clinical use and is probably responsible for its renal toxicity. The insolubility is caused by the 2-amino-3,4-dihydro-4-oxopyrimidine moiety of the drug which stabilizes the solid state by intermolecular hydrogen bonding. In examining this moiety we have removed the 2-amino group and now report on 2-desamino-10-propargyl-5,8-dideazafolic acid (8e) and four analogues with H, Me, Et, and allyl at N10. 3,4-Dihydro-4-oxo-6-methylquinazoline was solubilized by alkylating the lactam nitrogen with chloromethyl pivalate. Reaction with N-bromosuccinimide gave the corresponding 6-bromomethyl compound, which was coupled with diethyl N-(4-aminobenzoyl)-L-glutamate or the appropriate N-substituted derivative thereof. The quinazoline N3 nitrogen and carboxyl groups in the product were simultaneously deprotected by cold alkali in the final step to give the desired five antifolates. These were tested against L1210 TS and it was found that removal of the 2-amino group caused a slight (3-9-fold) loss of TS inhibition. 8e was only 8-fold a lesser TS inhibitor than the parent drug. Inhibition of rat liver dihydrofolate reductase was reduced by over 1 order of magnitude for three compounds tested. All five analogues were more cytotoxic to L1210 cells in culture than their 2-amino counterparts; 8e was 8.5-fold more active with an ID50 of 0.4 microM. This remarkable result probably owes to increased cellular penetration. 8e was 5-fold more soluble than 1 at pH 5.0 and greater than 340-fold more soluble at pH 7.4.