Laboratório de Dermatologia and Immunodeficiências, Departmento de Dermatologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
BMC Infect Dis. 2012 Oct 30;12:278. doi: 10.1186/1471-2334-12-278.
Cryptococcus neoformans causes meningitis and disseminated infection in healthy individuals, but more commonly in hosts with defective immune responses. Cell-mediated immunity is an important component of the immune response to a great variety of infections, including yeast infections. We aimed to evaluate a specific lymphocyte transformation assay to Cryptococcus neoformans in order to identify immunodeficiency associated to neurocryptococcosis (NCC) as primary cause of the mycosis.
Healthy volunteers, poultry growers, and HIV-seronegative patients with neurocryptococcosis were tested for cellular immune response. Cryptococcal meningitis was diagnosed by India ink staining of cerebrospinal fluid and cryptococcal antigen test (Immunomycol-Inc, SP, Brazil). Isolated peripheral blood mononuclear cells were stimulated with C. neoformans antigen, C. albicans antigen, and pokeweed mitogen. The amount of 3H-thymidine incorporated was assessed, and the results were expressed as stimulation index (SI) and log SI, sensitivity, specificity, and cut-off value (receiver operating characteristics curve). We applied unpaired Student t tests to compare data and considered significant differences for p<0.05.
The lymphotoxin alpha showed a low capacity with all the stimuli for classifying patients as responders and non-responders. Lymphotoxin alpha stimulated by heated-killed antigen from patients with neurocryptococcosis was not affected by TCD4+ cell count, and the intensity of response did not correlate with the clinical evolution of neurocryptococcosis.
Response to lymphocyte transformation assay should be analyzed based on a normal range and using more than one stimulator. The use of a cut-off value to classify patients with neurocryptococcosis is inadequate. Statistical analysis should be based on the log transformation of SI. A more purified antigen for evaluating specific response to C. neoformans is needed.
新型隐球菌在健康个体中引起脑膜炎和播散性感染，但更常见于免疫反应受损的宿主。细胞介导的免疫是对包括酵母感染在内的各种感染的免疫反应的重要组成部分。我们旨在评估针对新型隐球菌的特定淋巴细胞转化试验，以确定与神经隐球菌病（NCC）相关的免疫缺陷，作为真菌感染的主要原因。
健康志愿者、家禽养殖者和 HIV 血清阴性的神经隐球菌病患者接受细胞免疫反应测试。通过印度墨水染色脑脊液和隐球菌抗原试验（Immunomycol-Inc，SP，巴西）诊断隐球菌性脑膜炎。分离外周血单核细胞，用新型隐球菌抗原、白念珠菌抗原和美洲商陆丝裂原刺激。评估 3H-胸苷掺入量，并将结果表示为刺激指数（SI）和对数 SI、敏感性、特异性和截断值（受试者工作特征曲线）。我们应用未配对学生 t 检验比较数据，并认为 p<0.05 为差异有统计学意义。
淋巴毒素 alpha 对所有刺激物的反应能力都较低，无法将患者分类为反应者和非反应者。来自神经隐球菌病患者的加热杀死抗原刺激的淋巴毒素 alpha 不受 TCD4+细胞计数的影响，反应强度与神经隐球菌病的临床演变无关。
淋巴细胞转化试验的反应应基于正常范围并使用多种刺激物进行分析。使用截断值对神经隐球菌病患者进行分类是不够的。统计分析应基于 SI 的对数转换。需要更纯化的抗原来评估对新型隐球菌的特异性反应。
