Ho M, Davis T M, Silamut K, Bunnag D, White N J
Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Infect Immun. 1991 Jun;59(6):2135-9. doi: 10.1128/iai.59.6.2135-2139.1991.
Noninfected erythrocytes form rosettes around those infected with trophozoites and schizonts of Plasmodium falciparum in vitro. These rosettes are thought to contribute to the microvascular obstruction which underlies the pathophysiology of severe falciparum malaria. To determine whether the percentage of infected erythrocytes forming rosettes for a parasite isolates in vitro correlates with the in vivo severity of disease, we studied the rosette formation behavior of 35 isolates of P. falciparum from patients with uncomplicated, severe, and cerebral malaria. There was a wide variation in the degree of rosette formation (0 to 53%). Four parasite isolates formed rosettes well (30 to 53%), and seven isolates formed rosettes poorly or not at all (0 to 5%), while the majority of the isolates formed rosettes to various degrees between these two extremes. In this relatively small sample of patients, we were unable to demonstrate a significant association between in vitro rosette formation and patients with cerebral malaria or conscious patients with significant renal (serum creatinine greater than 200 mumol/liter) or hepatic dysfunction (serum bilirubin greater than 50 mumol/liter and aspartate aminotransferase greater than 50 Reitman-Frankel units). However, there was an inverse relationship between rosette formation and cytoadherence (r = -0.575, P less than 0.01) which could not be explained on the basis of steric hindrance. This finding suggests that cytoadherence and rosette formation properties are intrinsic to the parasites, with isolates having a greater propensity for one or the other but not both. Further studies are required to establish the occurrence and pathophysiological role of rosette formation in vivo.
在体外，未感染的红细胞会围绕被恶性疟原虫滋养体和裂殖体感染的红细胞形成玫瑰花结。这些玫瑰花结被认为会导致微血管阻塞，而微血管阻塞是重症恶性疟疾病理生理学的基础。为了确定体外寄生虫分离株形成玫瑰花结的感染红细胞百分比是否与疾病的体内严重程度相关，我们研究了来自非复杂性疟疾、重症疟疾和脑型疟疾患者的35株恶性疟原虫的玫瑰花结形成行为。玫瑰花结形成程度差异很大（0%至53%）。4株寄生虫分离株形成玫瑰花结的情况良好（30%至53%），7株分离株形成玫瑰花结的情况较差或根本不形成（0%至5%），而大多数分离株在这两个极端之间形成不同程度的玫瑰花结。在这个相对较小的患者样本中，我们无法证明体外玫瑰花结形成与脑型疟疾患者或有明显肾脏（血清肌酐大于200μmol/升）或肝功能障碍（血清胆红素大于50μmol/升且天冬氨酸转氨酶大于50赖特曼 - 弗兰克尔单位）的清醒患者之间存在显著关联。然而，玫瑰花结形成与细胞黏附之间存在负相关关系（r = -0.575，P小于0.01），这无法用空间位阻来解释。这一发现表明，细胞黏附和玫瑰花结形成特性是寄生虫固有的，分离株对其中一种或另一种特性有更大的倾向，但不会同时具备两种特性。需要进一步研究来确定体内玫瑰花结形成的发生情况及其病理生理作用。
