Ribosomal RNA analysis in the diagnosis of Diamond-Blackfan Anaemia

Diamond-Blackfan anaemia (DBA) is an inherited disease characterized by pure erythroid aplasia that has been tagged as a 'ribosomopathy'. We report a multi-centre study focused on the analysis of rRNA processing of 53 Italian DBA patients using capillary electrophoresis analysis of rRNA maturation of the 40S and 60S ribosomal subunits. The ratio of 28S/18S rRNA was higher in patients with mutated ribosomal proteins (RPs) of the small ribosomal subunit. In contrast, patients with mutated RPs of the large ribosomal subunit (RPLs) had a lower 28S/18S ratio. The assay reported here would be amenable for development as a diagnostic tool.status: publishe

Paroxysmal nocturnal hemoglobinuria clones in children with acquired aplastic anemia: a multicentre study.

A multicentre study evaluating the presence of glycosil phosphatidyl-inositol (GPI)-negative populations was performed in 85 children with acquired aplastic anemia (AA). A GPI-negative population was observed in 41% of patients at diagnosis, 48% during immune-suppressive therapy (IST), and 45% in patients off-therapy. No association was found between the presence of a GPI-negative population at diagnosis and the response to IST. In addition, the response rate to IST did not differ between the patients who were GPI-positive at diagnosis and later developed GPI-negative populations and the 11 patients who remained GPI-positive. Two patients with a GPI-negative population >10%, and laboratory signs of hemolysis without hemoglobinuria were considered affected by paroxysmal nocturnal hemoglobinuria (PNH) secondary to AA; no thrombotic event was reported. Excluding the 2 patients with a GPI-negative population greater than 10%, we did not observe a significant correlation between LDH levels and GPI-negative population size. In this study monitoring for laboratory signs of hemolysis was sufficient to diagnose PNH in AA patients. The presence of minor GPI-negative populations at diagnosis in our series did not influence the therapeutic response. As occasionally the appearance of a GPI-negative population was observed at cyclosporine (CSA) tapering or AA relapse, a possible role of GPI-negative population monitoring during IST modulation may need further investigation

Neutrophils, GPI-negative population and outcome of 30 AA patients followed since diagnosis and treated with IST as first line therapy.

<p>hATG = horse ATG; rATG = rabbit ATG; CSA = cyclosporin. In patients treated with hATG evaluation at 180 days showed 2 complete responders (CR, 14%), 7 partial-responders (PR, 50%) and 5 non-responders (NR, 36%), whereas in patients treated with rATG evaluation at 180 days showed 1 CR (7%), 2 PR (14%), 11 NR (79%) (2-tailed Fisher test p = 0.0542).</p><p>Among the 11 patients GPI negative at diagnosis, CR and PR were respectively 1 (9%) and 4 (36%), whereas NR were 6 (55%). Among the 19 patients GPI positive at diagnosis CR and PR were respectively 3 (16%) and 5 (26%), whereas NR were 11 (58%) (2-tailed Fisher test p = 1). In all the 4 GPI-negative patients who were treated with rATG the clone persisted at day +180, whereas it disappeared in 4/7 patients receiving hATG up-front.</p

Follow up of GPI-negative populations in two representative aplastic anemia (AA) patients.

<p>A: AA patient in IST. Variations of GPI-negative population size. The patient developed a frank PNH without hemoglobinuria. B: AA patient treated at first line with related HSCT and entered in the study at time of AA relapse after graft failure (falling of peripheral blood counts and autologous reconstutition with 100% recipient chimerism, after a previously full donor graft) A GPI-negative population was present at AA relapse and disappeared after starting immune-suppressive therapy with cyclosporine (persistent autologous reconstutition 100% recipient chimerism; persistent complete remission obtained).</p