Donor selection in living-donor lung transplantation for familial pulmonary fibrosis: A narrative review and single-center practical approach.

In Japan, living-donor lobar lung transplantation (LDLLT) remains an important therapeutic option because of the persistent shortage of brain-dead donors. Interstitial lung diseases (ILDs) are a major indication for transplantation; however, the use of biologically related donors raises concerns regarding shared genetic susceptibility. Approximately 20% of ILD patients have a family history of ILD, referred to as familial pulmonary fibrosis (FPF). FPF is defined as fibrotic ILD occurring in at least two first- or second-degree relatives and is associated with poor prognosis regardless of the presence of identifiable genetic variants. Furthermore, interstitial lung abnormalities have been reported in 14-22% of first-degree relatives of patients with FPF, suggesting a substantial latent risk of disease development both in donors and recipients. These findings have important implications for donor selection in LDLLT. At Kyoto University Hospital, first-degree relatives from affected lineages are generally excluded as donor candidates, whereas relatives from unaffected family branches may be considered after careful individual assessment. Even in cases without a family history, biologically related donor candidates should be adequately informed of the potential future risk of ILD. Future directions include the incorporation of genetic testing and telomere length assessment and the establishment of prospective cohorts to enable risk stratification and long-term outcome evaluation. In conclusion, the selection of donors for LDLLT in patients with FPF requires a cautious and individualized approach that integrates family history, clinical evaluation, and genetic information to balance donor safety with access to transplantation.