DBA EBV cell lines display altered large subunit pre-rRNA processing. RNA isolated from DBA EBV cell lines was probed with a 5.8S rRNA probe: lanes 1 to 4, healthy subject LCL; lane 5, deletion 1; lanes 6 to 8, DBA LCL with S19 mutations; lanes 9 to 12, non-S19-mutated DBA LCL. An altered 32S:12S ratio was observed in deletion 1 (*lane 5) and DBA019 EBV (+lane 11) cell lines. The sample in lane 12 also has increased 32S:12S with normal RPL35A transcript levels by qPCR and normal sequence for RPL35A and RPS19, suggesting additional gene defects may impair this pre-rRNA processing pathway in DBA.