Prommano Oranan, Chaisri Urai, Turner Gareth D H, Wilairatana Polrat, Ferguson David J P, Viriyavejakul Parnpen, White Nicholas J, Pongponratn Emsri
Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand..
Southeast Asian J Trop Med Public Health. 2005 Nov;36(6):1359-70.
We performed a retrospective study of 25 patients who died of severe falciparum malaria in Thailand and Vietnam using electron microscopy. The aims of the study were: to determine if there was any significant association between parasitized red blood cells (PRBC) sequestered in liver and spleen and particular pre-mortem clinical complications, and to compare the degree of parasite load between the liver and spleen within the same patients. PRBC sequestrations in each organ were compared with the pre-mortem parasitemia, to calculate the sequestration index (S.I.). The S.I. showed that the degree of PRBC sequestration in the spleen was higher than the liver (S.I. median = 3.13, 0.87, respectively) (p < 0.05). The results of quantitative ultrastructural study showed a significantly high parasite load in the liver of patients with jaundice, hepatomegaly and liver enzyme elevation (p < 0.05). We found a significant correlation between PRBC sequestration in the liver and a high serum bilirubin level, a high aspartate aminotransferase (AST) level and an increase in the size of the liver (Spearman's correlation coefficient = 0.688, 0.572, 0.736, respectively). Furthermore, a higher parasite load was found in the liver of patients with acute renal failure (ARF) compared to patients without ARF (p < 0.05). These findings suggest that PRBC sequestration in the liver is quantitatively associated with pre-mortem hepatic dysfunction and renal impairment. There was no significant difference between splenomegaly and PRBC sequestration. The size of a palpable spleen was not correlated with parasite load in the spleen. When ultrastructural features were compared between the two reticuloendothelial organs, we found that the spleen had more PRBC and phagocytes than the liver. The spleen of non-cerebral malaria (NCM) patients had more phagocytes than cerebral malaria (CM) patients. This observation reveals that the spleen plays a major role in malaria parasite clearance, and is associated with host defence mechanisms against malaria.
我们对泰国和越南25例死于重症恶性疟的患者进行了一项回顾性研究，采用电子显微镜观察。本研究的目的是：确定肝和脾中隔离的寄生红细胞（PRBC）与特定的死前临床并发症之间是否存在显著关联，并比较同一患者肝和脾内的寄生虫负荷程度。将每个器官中的PRBC隔离情况与死前寄生虫血症进行比较，以计算隔离指数（S.I.）。S.I.显示，脾中PRBC的隔离程度高于肝脏（S.I.中位数分别为3.13和0.87）（p<0.05）。定量超微结构研究结果显示，黄疸、肝肿大和肝酶升高患者的肝脏中寄生虫负荷显著较高（p<0.05）。我们发现肝脏中PRBC隔离与高血清胆红素水平、高天冬氨酸转氨酶（AST）水平以及肝脏大小增加之间存在显著相关性（Spearman相关系数分别为0.688、0.572、0.736）。此外，与无急性肾衰竭（ARF）的患者相比，急性肾衰竭患者肝脏中的寄生虫负荷更高（p<0.05）。这些发现表明，肝脏中PRBC隔离在数量上与死前肝功能障碍和肾功能损害相关。脾肿大与PRBC隔离之间无显著差异。可触及脾脏的大小与脾脏中的寄生虫负荷无关。当比较两个网状内皮器官的超微结构特征时，我们发现脾脏中的PRBC和吞噬细胞比肝脏更多。非脑型疟疾（NCM）患者的脾脏比脑型疟疾（CM）患者有更多的吞噬细胞。这一观察结果表明，脾脏在疟原虫清除中起主要作用，并与宿主抗疟防御机制有关。
