Lymphocyte transformation assay for C neoformans antigen is not reliable for detecting cellular impairment in patients with Neurocryptococcosis
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Data
2012-10-30
Autores
Rocha, Katya C.
Pinhal, Cinthia
Cavalcanti, Sonia
Vidal, Monica S. M.
Toscano, Matheus
Moraes-Vasconcelos, Dewton
Duarte, Alberto J. S.
Fonseca, Fernando L. A.
Abreu, Luiz Carlos de [UNESP]
Valenti, Vitor Engrácia [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Biomed Central Ltd.
Resumo
Background: 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.Methods: 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 H-3-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.Results: 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.Conclusion: 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.
Descrição
Palavras-chave
Lymphocytes, Antigens, Biases, Statistical, Cryptococcus, Methods, Cryptococcus neoformans
Como citar
Bmc Infectious Diseases. London: Biomed Central Ltd., v. 12, p. 8, 2012.