Late-onset cytomegalovirus pneumonia after autologous stem cell transplantation for angioimmunoblastic T-cell lymphoma: a case report.

This case report illustrates a diagnostic and therapeutic challenge in a highly immunocompromised host: severe pneumonia occurring late after autologous hematopoietic stem cell transplantation (auto-HSCT). A 57-year-old male with angioimmunoblastic T-cell lymphoma (AITL) presented with hypoxemic respiratory failure 1 year post-auto-HSCT, a timeline extending beyond the typical high-risk period for opportunistic infections. A profoundly low CD4+ T-cell count (172/µL) was identified as the key predisposing factor. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) enabled rapid, unbiased pathogen detection, confirming cytomegalovirus (CMV) pneumonia (viral load: 3.0 × 104 copies/mL) with Klebsiella pneumoniae coinfection. An integrated management strategy was instituted, comprising early empiric coverage for Pneumocystis jirovecii pneumonia, targeted therapy with ganciclovir and levofloxacin, and adjunctive immunomodulation using intravenous immunoglobulin and corticosteroids. This comprehensive approach resulted in full recovery, highlighting that the severity of immune suppression-rather than time since transplantation alone-determines infection risk. This case challenges the conventional time-based risk paradigm and supports immune-guided surveillance. It underscores the transformative role of mNGS in diagnosing complex infections in immunocompromised patients and advocates for a management paradigm that concurrently addresses pathogen eradication and host immune dysfunction.