Bronchiolitis obliterans
ICD-10 J44.8 · ICD-11 CA26.Y

Treatment of Bronchiolitis Obliterans in Lung Transplant Recipients with Grade A1 Acute Cellular Rejection and Allograft Dysfunction

Clinical Scenario

This protocol addresses lung transplant recipients in whom transbronchial lung biopsy demonstrates clinically significant minimal acute cellular rejection (Grade A1), accompanied by evidence of allograft dysfunction. Left unaddressed, this rejection grade carries risk for the development of bronchiolitis obliterans syndrome (BOS).

When Grade A1 Rejection Becomes Clinically Significant

Grade A1 rejection is considered clinically significant when it is associated with symptoms or objective signs of allograft dysfunction — for example, dyspnoea, fatigue, or new-onset cough, or measurable findings such as a decline in FEV1 or oxyhaemoglobin desaturation on ambulation.

Treatment Approach (Partial Overview)

The protocol for this scenario centres on augmented immunosuppression using a course of systemic steroids, aimed at reducing immune-mediated allograft injury and lowering the risk of BOS progression. The complete structured regimen — including the specific approach and management sequence — is set out in the full protocol.

Full structured regimen available via the link below.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1183/09031936.00107514

For lung transplant recipients who have clinically significant minimal acute cellular rejection (Grade A1) on transbronchial lung biopsy specimens, we suggest augmented immunosuppression with a course of systemic steroids to prevent the development of BOS (conditional recommendation, very low quality evidence).

We consider Grade A1 acute cellular rejection to be clinically significant if it is associated with clinical findings, such as symptoms (e.g. dyspnoea, fatigue or new-onset cough) or objective measurements (e.g. decline in FEV1 or oxyhaemoglobin desaturation with ambulation), that suggest the presence of allograft dysfunction.

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