Tagariello Giuseppe, Di Gaetano Rosanna, Sartori Roberto, Zanotto Daniela, Belvini Donata, Radossi Paolo, Risato Renzo, Roveroni Giovanni, Salviato Roberta, Tassinari Cristina, Toffano Nunzio
Servizio Trasfusionale, Centro Regionale per le Malattie del Sangue ed Emofilia, Ospedale di Castelfranco Veneto e Montebelluna, Azienda ULSS 8 Regione, 31033 Castelfranco Veneto, Italy.
Blood Transfus. 2009 Apr;7(2):111-6. doi: 10.2450/2008.0049-08.
It is not rare to observe in blood donors a level of haematocrit (Hct) above or close to the highest normal limit. In the case of blood donors the diagnosis and clinical evaluation of this alteration may be complicated by regular blood donations that can mask an underlying disease such as polycythaemia vera. Recently a single acquired mutation in the Janus kinase 2 gene (JAK2) on chromosome 9 was identified and it was found that the incidence of this mutation was high in patients with polycythaemia vera.
From the January 1, 2006 to December 31, 2006 all consecutive donors with a Hct above 50% if males (n=84) and 46% if females (n=19) underwent JAK2 mutation analysis. Seventy-nine donors (59 males and 20 females) whose Hct was normal at their last blood donation were randomly selected and used as controls.
Among the group of blood donors with a high Hct, we identified one donor who was positive for the JAK2 mutation. This man had a Hct of 50.6% at his last donation, while his average Hct in the preceding year was 51.7%. The prevalence of the JAK2 mutation could be estimated to be 1%, 0.6% or 0.02% in the three different populations considered: donors with a Hct level above the upper limit of normal, all tested donors or the entire donor cohort attending our transfusion service, respectively.
The present study suggests that apparently healthy subjects with repeatedly high levels of Hct may have the acquired mutation in JAK2. Laboratory screening tests for JAK2 may be offered to blood donors at transfusion services with expertise in molecular genetics.
在献血者中，观察到血细胞比容（Hct）水平高于或接近正常上限的情况并不罕见。对于献血者而言，这种改变的诊断和临床评估可能会因定期献血而变得复杂，因为献血可能掩盖诸如真性红细胞增多症等潜在疾病。最近，在9号染色体上的Janus激酶2基因（JAK2）中发现了一个单一的获得性突变，并且发现该突变在真性红细胞增多症患者中的发生率很高。
从2006年1月1日至2006年12月31日，所有连续的男性Hct高于50%（n = 84）和女性Hct高于46%（n = 19）的献血者都接受了JAK2突变分析。随机选择79名在上次献血时Hct正常的献血者（59名男性和20名女性）作为对照。
在Hct较高的献血者组中，我们鉴定出一名JAK2突变呈阳性的献血者。该男子在上次献血时Hct为50.6%，而前一年的平均Hct为51.7%。在所考虑的三个不同人群中，JAK2突变的患病率估计分别为：Hct水平高于正常上限的献血者为1%，所有接受检测的献血者为0.6%，或在我们输血服务中心的整个献血队列中为0.02%。
本研究表明，Hct水平反复升高的表面健康受试者可能存在JAK2获得性突变。对于具备分子遗传学专业知识的输血服务中心的献血者，可提供JAK2的实验室筛查检测。
