Hypomorphic RAG deficiency: impact of disease burden on survival and thymic recovery argues for early diagnosis and HSCT.

Patients with hypomorphic mutations in the RAG1 or RAG2 gene present with either Omenn syndrome or atypical combined immunodeficiency with a wide phenotypic range. Hematopoietic stem cell transplantation (HSCT) is potentially curative, but data are scarce. We report on a worldwide cohort of 60 patients with hypomorphic RAG variants who underwent HSCT, 78% of whom experienced infections (29% active at HSCT), 72% had autoimmunity, and 18% had granulomas pretransplant. These complications are frequently associated with organ damage. Eight individuals (13%) were diagnosed by newborn screening or family history. HSCT was performed at a median of 3.4 years (range 0.3-42.9 years) from matched unrelated donors, matched sibling or matched family donors, or mismatched donors in 48%, 22%, and 30% of the patients, respectively. Grafts were T-cell depleted in 15 cases (25%). Overall survival at 1 and 4 years was 77.5% and 67.5% (median follow-up of 39 months). Infection was the main cause of death. In univariable analysis, active infection, organ damage pre-HSCT, T-cell depletion of the graft, and transplant from a mismatched family donor were predictive of worse outcome, whereas organ damage and T-cell depletion remained significant in multivariable analysis (hazard ratio [HR] = 6.01, HR = 8.46, respectively). All patients diagnosed by newborn screening or family history survived. Cumulative incidences of acute and chronic graft-versus-host disease were 35% and 22%, respectively. Cumulative incidences of new-onset autoimmunity was 15%. Immune reconstitution, particularly recovery of naïve CD4+ T cells, was faster and more robust in patients transplanted before 3.5 years of age, and without organ damage. These findings support the indication for early transplantation.

Human Herpesvirus 8-Related Primary Effusion Lymphoma After Liver Transplantation.

Primary effusion lymphoma is a rare subclass of non-Hodgkin lymphoma associated with human herpesvirus 8 infection and principally seen in human immunodeficiency virus-positive patients. We report on the case of a 72-year-old human immunodeficiency virus-negative male with a hepatic transplant 10 years prior, who presented with a symptomatic right-sided pleural effusion and was found to have primary effusion lymphoma by flow cytometric and cytopathologic examination. Immunohistochemistry of his lymphoma cells was positive for human herpesvirus 8. Both he and his donor had no identifiable risk factors for human herpesvirus 8 infection. The patient was intolerant of antiviral therapy and chemotherapy, dying 7 months after diagnosis. Posttransplant primary effusion lymphoma is exceedingly rare and carries a very poor prognosis. Individualized treatment strategies are necessary given the scant body of published literature with guidance based solely on case reports.