Walker D H, Hudnall S D, Szaniawski W K, Feng H M
Department of Pathology, University of Texas Medical Branch, Galveston 77555-0609, USA.
Mod Pathol. 1999 May;12(5):529-33.
Cutaneous biopsies of five eschars and two rash lesions from five patients from New York City with documented rickettsialpox were examined by immunohistochemical methods with a monoclonal antibody directed against spotted fever group rickettsial lipopolysaccharide for the presence and cellular location of Rickettsia akari Rickettsiae were identified in all of the five patients, with good concordance of results for the same biopsy tissues with previously reported results by the direct immunofluorescence method. In contrast with immunofluorescence, which did not reveal the location of the organisms, immunohistochemical examination demonstrated R. akari to be in perivascular cells, morphologically resembling macrophages. Evaluation with double staining for rickettsiae and either CD68 or Factor VIII-related antigen revealed that the predominant infected cell type was CD68-positive macrophages, and only a rare rickettsia was detected in vascular endothelium, the major target cell for other rickettsioses. These results provide a diagnostic method for rickettsialpox and other spotted fever group rickettsioses and indicate that the elucidation of the pathogenesis of rickettsialpox must take into account that its target cell differs from that of Rocky Mountain spotted fever, boutonneuse fever, louse-borne typhus fever, and murine typhus.
对来自纽约市的5例确诊为立克次体痘的患者的5块焦痂和2处皮疹病变进行了皮肤活检，采用针对斑点热群立克次体脂多糖的单克隆抗体，通过免疫组化方法检测小蛛立克次体的存在及其细胞定位。在所有5例患者中均鉴定出立克次体，同一活检组织的结果与先前通过直接免疫荧光法报告的结果具有良好的一致性。与未显示病原体位置的免疫荧光不同，免疫组化检查显示小蛛立克次体存在于血管周围细胞中，形态上类似于巨噬细胞。用立克次体与CD68或VIII因子相关抗原进行双重染色评估显示，主要的感染细胞类型是CD68阳性巨噬细胞，在血管内皮细胞（其他立克次体病的主要靶细胞）中仅检测到罕见的立克次体。这些结果为立克次体痘和其他斑点热群立克次体病提供了一种诊断方法，并表明立克次体痘发病机制的阐明必须考虑到其靶细胞与落基山斑点热、纽扣热、虱传斑疹伤寒和鼠型斑疹伤寒的靶细胞不同。
