Center of Life, Universidade de Caxias do Sul, Caxias do Sul, RS, Brazil.
Department of Biochemistry, Institute of Chemistry, Universidade de São Paulo, São Paulo, SP, Brazil.
Microb Pathog. 2018 Aug;121:245-251. doi: 10.1016/j.micpath.2018.05.036. Epub 2018 May 23.
Rangelia vitalii is a protozoan of the Babesiidae family that parasitizes domestic and wild dogs in South American countries. The main laboratory findings in blood samples from animals infected by R. vitalii are anemia and thrombocytopenia. The aim of this study was to detect IgM and IgG immunoglobulins on the surface of red blood cells and platelets, as well as to determine the percentage of reticulated platelets and reticulocytes in dogs naturally infected by R. vitalii. Blood samples from twenty dogs seen at the Veterinary Hospital of the Federal University of Santa Maria (UFSM) were divided into two groups: the diseased group consisted of blood samples from 10 animals with the diagnosis of rangeliosis, and the healthy group (control) consisted of samples from 10 healthy animals. All diseased dogs showed normocytic normochromic anemia but showed no differences (p > 0.05) in reticulocyte counts compared to healthy dogs. Moreover, IgM and IgG immunoglobulins were detected on the surface of the plasma membrane of red blood cells from both groups, but the amounts did not differ between groups (p > 0.05). Thrombocytopenia in infected animals was classified as severe. The percentage of reticulated platelets was higher (p < 0.001) in diseased dogs than in healthy animals. Diseased animals showed more IgM immunoglobulins bound to the surface of platelets than did the healthy group (p < 0.001). However, the amount of IgG bound to the surface of platelets was not different between groups. In conclusion, we showed that R. vitalii caused immune-mediated thrombocytopenia since IgM immunoglobulins were found on the surface of platelets of diseased dogs. We suggest that the binding of immunoglobulins on platelet surfaces contributes to early destruction of these cells and, consequently, alterations in hemostasis. An increase in reticulated platelets was noted in response to thrombocytopenia, indicating active thrombopoiesis.
拉氏巴贝斯虫是一种寄生在南美的家犬和野犬中的巴贝斯科原虫。感染拉氏巴贝斯虫的动物血液样本的主要实验室发现是贫血和血小板减少症。本研究的目的是检测红细胞和血小板表面的 IgM 和 IgG 免疫球蛋白，以及确定自然感染拉氏巴贝斯虫的犬的网织血小板和网织红细胞的百分比。从圣玛丽亚联邦大学兽医医院就诊的 20 只狗的血液样本分为两组：患病组由 10 只被诊断为拉氏病的动物的血液样本组成，健康组（对照组）由 10 只健康动物的样本组成。所有患病犬均表现为正细胞正色素性贫血，但与健康犬相比，网织红细胞计数无差异（p>0.05）。此外，两组红细胞的质膜表面均检测到 IgM 和 IgG 免疫球蛋白，但两组之间的数量无差异（p>0.05）。感染动物的血小板减少症被归类为严重。感染动物的网织血小板百分比较高（p<0.001）。患病犬的血小板表面结合的 IgM 免疫球蛋白多于健康组（p<0.001）。然而，结合到血小板表面的 IgG 量在两组之间没有差异。总之，我们表明拉氏巴贝斯虫引起了免疫介导的血小板减少症，因为患病犬的血小板表面发现了 IgM 免疫球蛋白。我们认为，免疫球蛋白结合到血小板表面有助于这些细胞的早期破坏，进而导致止血异常。由于血小板减少症，网织血小板增加，表明活跃的血小板生成。
