Paroxysmal nocturnal haemoglobinuria phenotype cells and leucocyte subset telomere length in childhood acquired aplastic anaemia

Summary The significance of paroxysmal nocturnal haemoglobinuria (PNHpos) cells and leucocyte subset telomere lengths in paediatric aplastic anaemia (AA) is unknown. Among 22 children receiving immunosuppressive therapy (IST) for AA, 73% (16/22) were PNHpos, of whom 94% achieved at least a partial response (PR) to IST; 11/16 (69%) achieved complete response (CR). Only 2/6 (33%) PNHneg patients achieved PR. PNHpos patients were less likely to fail IST compared to PNHneg patients (odds ratio 0·033; 95% confidence interval 0·002–0·468; P = 0·012). Children with AA had short granulocyte (P = 7·8 × 10−9), natural killer cell (P = 6·0 × 10−4), naive T lymphocyte (P = 0·002) and B lymphocyte (P = 0·005) telomeres compared to age-matched normative data.