Inmunofenotipificación de linfocitos T como marcador diagnóstico de sepsis neonatal tardía

Résumé

Background Given the high risks associated with neonatal sepsis, there is a need for a diagnostic marker that would predict the disease before the results of blood or cerebrospinal fluid cultures are available. We evaluated changes in the CD4+ T lymphocyte immunophenotype in neonates with late-onset sepsis to try to improve the test combinations currently used (C reactive protein, immature:total neutrophil ratio, leukocytosis). Patients and methods We performed a prospective cohort study in 24 neonates with late-onset sepsis and 48 non-infected controls with a gestational age of 37 weeks or less. CD4+ T lymphocyte subpopulations in peripheral blood samples were identified by labeling with monoclonal antibodies and quantified by flow cytometry. Diagnostic performance curves were constructed by logistic regression. Results As a marker of late-onset neonatal sepsis, a percentage of CD4+/CD45RO+/CD45RA– T lymphocytes of > 3.5% showed a sensitivity of 94.1 %, specificity of 69.2 %, positive predictive value of 80.0 %, negative predictive value of 90.0 %, and odds ratio of 36.0 (p < 0.001). When we combined this marker with a C-reactive protein level of > 10.0 mg/L, the specificity of this combination of tests increased to 94.7 % and the positive predictive value to 85.7%. Conclusions A percentage of CD4+/CD45RO+/CD45RA– T lymphocytes of > 3.5 % is an effective indicator of late-onset neonatal sepsis in preterm infants. If this marker is combined with a C-reactive protein level of > 10.0 mg/l, its diagnostic performance is improved