Incompatible erythrocyte transfusion with lipopolysaccharide induces acute lung injury in a novel rat model

RLS-0071, a novel anti-inflammatory agent, significantly reduced inflammatory biomarkers in a randomised human evaluation of mechanisms and safety study

Background

This study was a randomised, double-blind, placebo-controlled study intended to establish the translatability of the RLS-0071 mechanisms of action from animal disease models to humans by inhibiting neutrophil-mediated inflammation at the tissue level and major inflammatory biomarkers. We hypothesised that RLS-0071 inhibits a temporary neutrophil-mediated inflammation in the lungs induced by inhalation of low-dose lipopolysaccharide (LPS) in healthy participants.

Methods

Participants were randomised to one of three arms to receive inhaled LPS followed by three doses of either low-dose (10 mg·kg-1) or high-dose (120 mg·kg-1 loading dose followed by two doses of 40 mg·kg-1) RLS-0071 i.v. or placebo (saline) every 8 h. Biomarkers evaluating inflammatory responses, with absolute neutrophil counts in induced sputum as the primary end-point, were collected before and at 6 and 24 h after LPS challenge.

Results

Active treatment with RLS-0071 showed a similar safety profile to participants receiving placebo. RLS-0071 significantly decreased the numbers of neutrophils in sputum at 6 h post LPS by approximately half (p=0.04). Neutrophil effectors myeloperoxidase, neutrophil elastase and interleukin-1β in sputum were also significantly decreased at 6 h for RLS-0071 compared with placebo. Several biomarkers showed trends suggesting sustained decreases for RLS-0071 versus placebo at 24 h.

Conclusion

This clinical trial demonstrated that RLS-0071 was safe and well tolerated and modulated neutrophil-mediated inflammation in humans after inhaled LPS challenge, consistent with results from prior animal model studies.

Clinical Factors of Blood Transfusion-Related Acute Lung Injury and Changes in Levels of Treg-Related Cytokines

Objective

Analysis of clinical factors and changes in regulatory T cell (Treg)-related cytokine levels in transfusion-associated acute lung injury (TRALI).

Methods

62 patients who underwent blood transfusion and developed TRALI (TRALI group) in our hospital between January 2018 and December 2021 and 58 patients who did not develop TRALI (non-TRALI group) from blood transfusion were selected to collect clinical data from patients and construct a logistic regression model to analyze clinical risk factors for TRALI. Based on the prognosis of TRALI patients, they were divided into survival group (50 cases) and death group (12 cases), and serum CD4 + CD25 + Treg and Treg-related cytokines (interleukin 10 (IL-10), transforming growth factor-β (TGF-β)) levels were compared between the two groups, and the correlation between CD4 + CD25 + Treg and IL-10 and TGF-β was analyzed by Pearson.

Results

The differences in smoking history, human leukocyte antigen (HLA) antibody II, pretransfusion shock, and CD4 + CD25 + Treg between the TRALI group and non-TRALI group were statistically significant (P < 0.05). Logistic regression analysis showed that HLA antibody II and increased CD4 + CD25 + Treg were independent risk factors of TRALI (P < 0.05). The levels of CD4 + CD25 + Treg, IL-10, and TGF-β in the death group were significantly higher than those in the survival group (P < 0.05). CD4 + CD25 + Treg was positively correlated with levels of IL-10 and TGF-β (P < 0.05).

Conclusion

Elevated HLA antibody II and CD4 + CD25 + Treg are the main clinical risk factors for TRALI, and CD4 + CD25 + Treg may be involved in immunosuppression by increasing the expression levels of IL-10 and TGF-β. Early clinical monitoring of changes in Treg-related cytokine levels can provide some guidance for prognostic assessment of TRALI patients.