Moroff G, Wagner S, Benade L, Dodd R Y
American Red Cross, Jerome H. Holland Laboratory for the Biomedical Sciences, Rockville, Maryland 20855.
Blood Cells. 1992;18(1):43-54; discussion 54-6.
A wide variety of viruses are inactivated by psoralen compounds in the presence of ultraviolet A light (UVA). Use of aminomethyltrimethylpsoralen (AMT) and UVA is being evaluated as a method to inactivate viruses that may be present in platelet suspensions prepared for transfusion. Studies have been conducted to assess how variation in various environmental parameters influences the extent of viral inactivation and the retention of platelet properties. Most notably, it was determined that increasing levels of plasma progressively inhibited the inactivation of model viruses. As a result, experiments were routinely conducted at a plasma level of approximately 14.5%, using 40 micrograms/ml AMT, which was determined to be optimal when using this reduced plasma level. The reduced plasma level was achieved by dilution with a nonplasma medium that has been shown to be satisfactory for storage of platelets. Under these conditions, about 5 logs of vesicular stomatitis virus (VSV), pseudorabies, and phi 6 inactivation were achieved. Variation of platelet and leukocyte counts, within normal levels, had a minimal effect on extent of viral inactivation. Although oxygen level (mean levels, 97.9 mm Hg versus 19.2 mm Hg) had only a small influence on viral inactivation with 2.4, 4.8, and 7.2 J/cm2 of UVA (equivalent to 1-3 minutes of exposure), in vitro platelet properties, such as medium pH, morphology characteristics, and aggregation response, were better retained with a longer exposure time at the reduced oxygen level. With normal oxygen (97.9 mm Hg), platelet properties declined substantially relative to untreated controls (no UVA, no AMT) on exposure to 4.8 J/cm2. Our studies have identified two sets of conditions that provide about 5 logs of virus inactivation without extensively altering platelet in vitro properties.
在紫外线A(UVA)存在的情况下,多种病毒会被补骨脂素化合物灭活。氨甲基三甲基补骨脂素(AMT)和UVA的联合使用正在作为一种灭活可能存在于输血用血小板悬液中的病毒的方法进行评估。已经开展了研究,以评估各种环境参数的变化如何影响病毒灭活程度以及血小板特性的保留情况。最值得注意的是,已确定血浆水平的升高会逐渐抑制模型病毒的灭活。因此,实验通常在血浆水平约为14.5%的条件下进行,使用40微克/毫升的AMT,在这种降低的血浆水平下,该浓度被确定为最佳浓度。通过用已证明对血小板储存令人满意的非血浆介质进行稀释来实现降低的血浆水平。在这些条件下,水泡性口炎病毒(VSV)、伪狂犬病病毒和phi 6病毒的灭活程度达到了约5个对数。血小板和白细胞计数在正常水平内的变化对病毒灭活程度的影响最小。尽管氧气水平(平均水平,97.9毫米汞柱对19.2毫米汞柱)对2.4、4.8和7.2焦/平方厘米的UVA照射(相当于1 - 3分钟的暴露时间)下的病毒灭活仅有很小的影响,但在较低氧气水平下延长暴露时间能更好地保留体外血小板特性,如培养基pH值、形态特征和聚集反应。在正常氧气水平(97.9毫米汞柱)下,暴露于4.8焦/平方厘米时,血小板特性相对于未处理的对照(无UVA,无AMT)大幅下降。我们的研究确定了两组条件,在不广泛改变血小板体外特性的情况下可实现约5个对数的病毒灭活。