Post-transplant food anaphylaxis in an adult cord blood transplant recipient (Ms. No. IJHM-D-20-01037R1)

Transplant-acquired allergy in HCT-recipients: Reference for clinical management

Transplant-acquired allergy (TAA) is well known in pediatric patients undergoing liver transplantation. Regarding allogeneic hematopoietic cell transplantation (allo-HCT), the clinical characteristics of TAA have not been fully elucidated. Clinical manifestations of TAA include eczematous dermatitis, allergic rhinitis, and asthma. It is known that allergic diseases are transferable from allergic donors to non-allergic recipients via allo-HCT. The potential mechanism is the transfer of allergen-specific memory B cells resulting in Th2-skewed allergy-specific immune responses. Retrospective studies have suggested that cord blood transplantation (CBT) and the immunosuppressant tacrolimus have a significant impact on the development of TAA. The reported prevalence varies according to study design, diagnostic methods, and study population, and the suspected allergens vary widely among individuals. Prospective cohort studies and further mechanistic investigations are warranted to provide robust evidence on the prevalence and risk factors associated with TAA.

The risk of donor-acquired allergy in solid-organ transplant recipients: A systematic review

BACKGROUND

Donor-acquired allergy (DAA) occurs when donors transfer their allergies to recipients through solid-organ transplant (SOT). However, the risk of DAA in recipients of organs from allergic donors has not been systematically characterized.

OBJECTIVE

To synthesize the available evidence on the risk of DAA in SOT recipients.

METHODS

We searched Embase and MEDLINE databases for original and peer-reviewed articles related to transplant allergy since database inception to February 11, 2024. Two reviewers independently screened records, extracted data, and assessed risk of bias.

RESULTS

The review included 24 studies with 747 SOT recipients and their 135 allergic donors in the category of food, drug, or venom. Only 40 recipients (5.4%) underwent allergy testing to donor allergens, and 23 of them had the testing done before an exposure to donor allergens. Among the 30 recipients (4.0%) who were diagnosed with having DAA based on a clinical reaction or positive allergy testing result, 19 (2.5%) had anaphylaxis to donor allergens. Only the type of SOT (lung or liver) was associated with an increased risk of DAA (odds ratio 88.0, 95% CI 22.5-481.3), with no association found for other organs.

CONCLUSION

Despite the uncommon occurrence, recipients of organs from allergic donors could be at risk of severe allergic reactions to donor allergens. Although infrequently performed, allergy testing to donor allergens can effectively assess the risk of developing DAA. These findings highlight the risk of DAA and underscore the importance of proactive allergy assessment to prevent unnecessary anaphylaxis in this vulnerable population.

Transplant-Acquired Food Allergy in Children

BACKGROUND

Organ transplantation in children is a vital procedure for those with end-stage organ failure, but it has been linked to the development of post-transplant allergies, especially food allergies. This phenomenon, known as transplant-acquired food allergy (TAFA), is becoming increasingly recognized, though its mechanisms remain under investigation. Pediatric transplant recipients often require lifelong immunosuppressive therapy to prevent graft rejection, which can alter immune function and heighten the risk of allergic reactions. Our review aimed to gather the latest evidence on TAFA.

METHODS

We conducted a PubMed search from 25 June to 5 July 2024, using specific search terms, identifying 143 articles. After screening, 36 studies were included: 24 retrospective studies, 1 prospective study, 2 cross-sectional researches, and 9 case reports/series.

RESULTS

Most studies focused on liver transplants in children. The prevalence of food allergies ranged from 3.3% to 54.3%. Tacrolimus, alongside corticosteroids, was the most commonly used immunosuppressive therapy. In addition to food allergies, some patients developed atopic dermatitis, asthma, and rhinitis. Allergic symptoms typically emerged within a year post-transplant, with common allergens including milk, eggs, fish, nuts, soy, wheat, and shellfish. Both IgE-mediated and non-IgE-mediated reactions were observed, with treatment often involving the removal of offending foods and the use of adrenaline when necessary.

CONCLUSIONS

Consistent immunological monitoring, such as skin prick tests and IgE level assessments, is essential for early detection and management of allergies in these patients. Understanding the link between transplantation and allergy development is crucial for improving long-term outcomes for pediatric transplant recipients.

Two cases of transplant-acquired food allergy who developed resensitization after a negative oral food challenge

BACKGROUND

Cases of food allergy after hematopoietic stem cell and solid organ transplantation in previously nonallergic transplant recipients were reported as transplant-acquired food allergy (TAFA), but information about its long-term outcome is still limited. A phenomenon where patients reacquire food allergy by resuming daily consumption after a negative oral food challenge has not yet been reported.

CASE PRESENTATION

We report two cases of TAFA after liver transplantation and cord blood transplantation. In each case, the threshold of daily consumption to cause allergic symptoms decreased when a negative oral food challenge was obtained.

CONCLUSIONS

Our cases show an importance of gastrointestinal tract as a route of food sensitization because thresholds that caused allergic reactions decreased during their resuming process. We need to be careful with possible resensitization once a negative substantial dose was confirmed.

The emerging role of nutritional support in the supportive care of pediatric patients undergoing hematopoietic stem cell transplantation

Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT) represents a potentially curative strategy for many oncological, hematological, metabolic, and immunological diseases in children. The continuous effort in ameliorating supportive care represents one of the cornerstones in the improvement of outcome in these patients. Nowadays, more than ever nutritional support can be considered a key feature. Oral feeding in the early post-transplant period is severely impaired because of mucositis due to conditioning regimen, characterized by, mainly by vomiting, anorexia, and diarrhea. Gastrointestinal acute graft-versus-host-disease (GvHD), infections and associated treatments, and other medications, such as opioids and calcineurin inhibitors, have also been correlated with decreased oral intake. The consequent reduction in caloric intake combined with the catabolic effect of therapies and transplantation-related complications with consequent extended immobilization, results in a rapid deterioration of nutritional status, which is associated with decreased overall survival and higher complication rates during treatment. Thus, nutritional support during the early post-transplantation period becomes an essential and challenging issue for allo-HSCT recipients. In this context, the role of nutrition in the modulation of the intestinal flora is also emerging as a key player in the pathophysiology of the main complications of HSCT. The pediatric setting is characterized by less evidence, considering the challenge of addressing nutritional needs in this specific population, and many questions are still unanswered. Thus, we perform a narrative review regarding all aspects of nutritional support in pediatric allo-HSCT recipients, addressing the assessment of nutritional status, the relationship between nutritional status and clinical outcomes and the evaluation of the nutritional support, ranging from specific diets to artificial feeding.