Sawyer Lynette, Hanson Deborah, Castro Grace, Luckett William, Dubensky Thomas W, Stassinopoulos Adonis
Cerus Corporation, Concord, California 94520, USA.
Transfusion. 2007 Jun;47(6):1062-70. doi: 10.1111/j.1537-2995.2007.01237.x.
The human erythrovirus B19 (B19) is a small (18- to 26-nm) nonenveloped virus with a single-stranded DNA genome of 5.6 kb. B19 is clinically significant and is also generally resistant to pathogen inactivation methods. Photochemical treatment (PCT) with amotosalen and ultraviolet A (UVA) inactivates viruses, bacteria, and protozoa in platelets (PLTs) and plasma prepared for transfusion. In this study, the capacity of PCT to inactivate B19 in human PLT concentrates was evaluated.
B19 inactivation was measured by a novel enzyme-linked immunosorbent spot (ELISPOT) erythroid progenitor cell infectivity assay and by inhibition of long-range (up to 4.3 kb) polymerase chain reaction (PCR), under conditions where the whole coding region of the viral genome was amplified. B19-infected plasma was used to test whether incubation of amotosalen with virus before PCT enhanced inactivation compared to immediate PCT.
Inactivation of up to 5.8 log of B19 as measured by the infectivity assay, or up to 6 logs as measured by PCR inhibition can be achieved under non-limiting conditions. Inactivation efficacy was found to increase with incubation prior to UVA illumination. Without incubation prior to illumination 2.1 +0.4 log was inactivated as determined by infectivity assay. When measured by PCR inhibition, inactivation varied inversely with amplicon size. When primers that spanned the entire coding region of the B19 genome were used, maximum inhibition of PCR amplification was demonstrated.
Under defined conditions, PCT with amotosalen combined with UVA light can be used to inactivate B19, a clinically significant virus that can be transmitted through blood transfusion, and heretofore has been demonstrated to be refractory to inactivation.
人细小病毒B19（B19）是一种小型（18至26纳米）无包膜病毒，具有5.6 kb的单链DNA基因组。B19具有临床意义，并且通常对病原体灭活方法具有抗性。用氨甲环酸和紫外线A（UVA）进行光化学处理（PCT）可使用于输血的血小板（PLT）和血浆中的病毒、细菌和原生动物失活。在本研究中，评估了PCT灭活人血小板浓缩物中B19的能力。
通过一种新型酶联免疫吸附斑点（ELISPOT）红细胞祖细胞感染性测定法以及在扩增病毒基因组整个编码区的条件下抑制长距离（长达4.3 kb）聚合酶链反应（PCR）来测量B19的灭活情况。使用感染B19的血浆来测试与立即进行PCT相比，在PCT之前将氨甲环酸与病毒孵育是否能增强灭活效果。
在非限制性条件下，通过感染性测定法测量可实现高达5.8 log的B19灭活，通过PCR抑制测量可实现高达6 log的灭活。发现灭活效果随着UVA照射前的孵育而增加。在照射前不进行孵育时，通过感染性测定法确定灭活了2.1±0.4 log。通过PCR抑制测量时，灭活与扩增子大小成反比。当使用跨越B19基因组整个编码区的引物时，显示出对PCR扩增的最大抑制。
在规定条件下，氨甲环酸联合UVA光的PCT可用于灭活B19，B19是一种可通过输血传播的具有临床意义的病毒，迄今为止已证明其对灭活具有抗性。
