CD4+CD25+Foxp3+ T Regulatory Cells Protect Against Murine Antibody-Mediated Transfusion-Related Acute Lung Injury (TRALI)
Bibliographic record
Abstract
Abstract Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related fatalities and is characterized by acute respiratory distress following transfusion of blood products. Frequently, donor antibodies present in the transfused blood product are involved, such as anti-human leukocyte antigen (HLA) antibodies or anti-human neutrophil antigen (HNA) antibodies. Several animal models of TRALI have contributed to understanding the pathogenesis which, however, is still incompletely understood. Several cell types have also been suggested to be involved in antibody-mediated TRALI, including neutrophils, endothelial cells and monocytes. Most of the animal models are based on a two-hit paradigm, where the first hit is based on "patient predisposition", such as sepsis or chronic alcohol abuse, while the second hit is delivered in the form of "transfusion factors", such as antibodies present in the transfused blood product. Although most studies have focused on factors contributing to the development of antibody-mediated TRALI, the factors and mechanisms in place to protect against antibody-mediated TRALI have been underexplored. Adoptive transfer of lymphocytes into recipient severe combined immunodeficient (SCID) mice, in which the well-established TRALI inducing anti-MHC class I antibody clone 34-1-2s was injected, was previously shown to rescue TRALI induction by 34-1-2s. Here we describe, using a murine BALB/c antibody-mediated TRALI model based on injection of 34-1-2s, that CD4 T cells, and more specifically, CD4+CD25+Foxp3+ T regulatory cells (Tregs), are responsible for protection against murine antibody-mediated TRALI. Specific in vivo depletion of CD4+ T cells, or targeted in vivo depletion of Tregs, resulted in severe lung damage after 34-1-2s infusion, as determined by increased lung wet-to-dry ratios (a measure for pulmonary edema), generally greater than 5, indicative of severe pulmonary edema. This was accompanied by significant hypothermia, increased values of the neutrophil chemoattractant macrophage inflammatory protein 2 (MIP-2: equivalent of human IL-8), and increased pulmonary neutrophil accumulation, all compared to control groups. In contrast, systematic in vivo depletion of CD8+ T cells, B cells or monocytes, did not result in significant lung damage. Co-depletion of CD4+ T cells together with monocytes rescued the TRALI induction by 34-1-2s, validating the pathogenic role of monocytes in murine antibody-mediated TRALI induction. Based on MIP-2 values and in vitro studies, we suggest that Tregs suppress monocytes in order to prevent antibody-mediated TRALI. Overall, a novel first hit in TRALI induction could be identified in conditions that cause a decrease in Treg number or function, which could also explain the increased risk for human TRALI in cases of chronic alcohol abuse. In addition, therapies aimed at restoring Treg numbers or function may prove to be a novel therapeutic approach in antibody-mediated TRALI. Disclosures No relevant conflicts of interest to declare.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".