Abstract 169

Thrombocytopenia frequently occurs in septic neonates. Postulated mechanisms are increased platelet (PLT) consumption, decreased PLT production or a combination of both. PLT production is regulated by hematopoietic cytokines, including Tpo, interleukin (IL)-3, IL-11, and IL-6, which act on the megakaryocyte stimulating its proliferation and differentiation. Previous studies have shown increases in cytokine levels, such as IL-6, in neonates with infection. However, it is not known whether Tpo levels change in the blood of septic neonates and if they correlate with PLT counts. To answer these questions, Tpo levels and PLT counts were assessed in twenty-six blood specimens drawn from neonates who were suspected of having sepsis and seventeen from age-matched control infants. Neonates were evaluated for sepsis if they presented respiratory distress, temperature instability, hyper- hypoglicemia, or metabolic acidosis. Evaluation included complete blood cell counts (CBC), leukocyte differential counts, band/total neutrophil ratio, CRP, cultures of blood, and when appropriate, urine, cerebrospinal fluid, and bronchoalveolar lavage fluid. A 500µL blood of leftover samples used for work-up of sepsis or routine laboratory studies was immediately centrifuged and the plasma stored for Tpo assessment (ELISA). Neonates with suspicion of sepsis were retrospectively divided into two groups: Gr.I (proven sepsis), neonates with positive blood and/or cerebrospinal culture results, and Gr.II (infection other than sepsis) including infants with pneumonia, NEC, and UTI. Infants with proven sepsis(Gr.I) had the highest mean Tpo level (pg/mL) 1,692±(SEM)588 and the lowest mean PLT count (cells/µL) (129,571±65,446) and these values were significantly higher than those of infected infants(Tpo:471±146; PLT: 261,210±36,858) and controls(Tpo:161±59; PLT:343,529±34,709). The correlation coefficient(Pearson) calculated between Tpo levels and PLT counts was -0.494(P<0.0001). We conclude that Tpo increased in the plasma of septic neonates and correlates inversely with the PLT count.