[Diagnosis and treatment of nocturnal paroxysmal hemoglobinuria]

Diagnostic screening of paroxysmal nocturnal hemoglobinuria: Prospective multicentric evaluation of the current medical indications

BACKGROUND

Although consensus guidelines have been proposed in 2010 for the diagnostic screening of paroxysmal nocturnal hemoglobinuria (PNH) by flow cytometry (FCM), so far no study has investigated the efficiency of such medical indications in multicentric vs. reference laboratory settings.

METHODS

Here we evaluate the efficiency of consensus medical indications for PNH testing in 3,938 peripheral blood samples submitted to FCM testing in 24 laboratories in Spain and one reference center in Brazil.

RESULTS

Overall, diagnostic screening based on consensus medical indications was highly efficient (14% of PNH⁺ samples) both in the multicenter setting in Spain (10%) and the reference laboratory in Brazil (16%). The highest frequency of PNH⁺ cases was observed among patients screened because of bone marrow (BM) failure syndrome (33%), particularly among those with aplastic anemia (AA; 45%) and to a less extent also a myelodysplastic syndrome (MDS; 10%). Among the other individuals studied, the most efficient medical indications for PNH screening included: hemolytic anemia (19%), hemoglobinuria (48%) and unexplained cytopenias (9%). In contrast, only a minor fraction of the patients who had been submitted for PNH testing because of unexplained thrombosis in the absence of cytopenia, were positive (0.4%).

CONCLUSIONS

In summary, our results demonstrate that the current medical indications for PNH screening by FCM are highly efficient, although improved screening algorithms are needed for patients presenting with thrombosis and normal blood cell counts. © 2016 International Clinical Cytometry Society.

GPI-anchor and GPI-anchored protein expression in PMM2-CDG patients

BACKGROUND

Mutations in PMM2 impair phosphomannomutase-2 activity and cause the most frequent congenital disorder of glycosylation, PMM2-CDG. Mannose-1-phosphate, that is deficient in this disorder, is also implicated in the biosynthesis of glycosylphosphatidyl inositol (GPI) anchors.

OBJECTIVE

To evaluate whether GPI-anchor and GPI-anchored proteins are defective in PMM2-CDG patients.

METHODS

The expression of GPI-anchor and seven GPI-anchored proteins was evaluated by flow cytometry in different cell types from twelve PMM2-CDG patients. Additionally, neutrophil CD16 and plasma hepatic proteins were studied by Western blot. Transferrin glycoforms were evaluated by HPLC.

RESULTS

Patients and controls had similar surface expression of GPI-anchor and most GPI-anchored proteins. Nevertheless, patients displayed a significantly diminished binding of two anti-CD16 antibodies (3G8 and KD1) to neutrophils and also of anti-CD14 (61D3) to monocytes. Interestingly, CD16 immunostaining and asialotransferrin levels significantly correlated with patients' age. Analysis by flow cytometry of CD14 with MΦP9, and CD16 expression in neutrophils by Western blot using H-80 ruled out deficiencies of these antigens.

CONCLUSIONS

PMM2 mutations do not impair GPI-anchor or GPI-anchored protein expression. However, the glycosylation anomalies caused by PMM2 mutations might affect the immunoreactivity of monoclonal antibodies and lead to incorrect conclusions about the expression of different proteins, including GPI-anchored proteins. Neutrophils and monocytes are sensitive to PMM2 mutations, leading to abnormal glycosylation in immune receptors, which might potentially affect their affinity to their ligands, and contribute to infection. This study also confirms less severe hypoglycosylation defects in older PMM2-CDG patients.

[Myelodysplastic syndrome in the elderly: comprehensive geriatric assessment and therapeutic recommendations]

The onset of myelodysplastic syndromes (MDS) is usually around the age of 70. Despite this, most clinical trials are restricted to younger subjects. Thus, the management of elderly patients with MDS is not always optimal. Physiologically, elderly patients show characteristics that differ from those of younger patients and that condition their pharmacological treatment. In this regard, the comprehensive geriatric assessment (CGA) becomes particularly important. This document gathers conclusions from the 1(st) Meeting of Members of the Sociedad Española de Medicina Geriátrica and the Sociedad Española de Hematología y Hemoterapia, with the objective of proposing the establishment of CGA instruments to assist in the decision-making process of elderly patients with MDS. The results of this consensus document will focus on the diagnosis, prognosis, treatment and management of adverse events in this age group.