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Pediatrics16 papers

Neonatal leukemoid reaction

Last edited: 4/15/2026

Overview

Neonatal leukemoid reaction (NLR) is a reactive condition characterized by hematological abnormalities resembling leukemia, including markedly elevated white blood cell counts, but without the presence of malignant cells 1. It often occurs in the context of fetal inflammatory response syndrome and can be associated with elevated serum granulocyte colony-stimulating factor (G-CSF) and interleukin-6 levels 1.

Diagnosis

  • Key Diagnostic Criteria: White blood cell count ≥ 40 × 10^9/L 1.
  • Recommended Tests: Complete blood count (CBC) with differential, serum G-CSF levels, and interleukin-6 levels 1.
  • Grading: Not universally standardized; clinical context and associated symptoms are crucial 1.
  • Management

  • First-Line Treatments: Supportive care including hydration, monitoring for sepsis, and management of underlying conditions 1.
  • Adjunctive Treatments: No specific drug doses mentioned; focus on addressing precipitating factors such as infections or inflammatory conditions 1.
  • Special Populations

  • Pregnancy/Neonatal Context: NLR often emerges in neonates, particularly in association with fetal inflammatory response syndrome 1.
  • Comorbidities: Associated with conditions like infections and inflammatory states, requiring tailored management 1.
  • Key Recommendations

  • Evaluate neonates with markedly elevated white blood cell counts for NLR, considering serum G-CSF and interleukin-6 levels for diagnostic support (Evidence: Moderate 1).
  • Prioritize supportive care and identification/treatment of underlying triggers such as infections in the management of NLR (Evidence: Moderate 1).
  • Monitor for and manage potential complications related to fetal inflammatory response syndrome in neonates presenting with NLR (Evidence: Expert opinion 1).
  • References

    1 Nakamura T, Hatanaka D, Kusakari M, Kashima K, Takizawa Y, Takahashi H et al.. Neonatal Leukemoid Reaction with Fetal Inflammatory Response Syndrome Is Associated with Elevated Serum Granulocyte Colony Stimulating Factor and Interleukin-6. The Tohoku journal of experimental medicine 2018. link

    Original source

    1. [1]
      Neonatal Leukemoid Reaction with Fetal Inflammatory Response Syndrome Is Associated with Elevated Serum Granulocyte Colony Stimulating Factor and Interleukin-6.Nakamura T, Hatanaka D, Kusakari M, Kashima K, Takizawa Y, Takahashi H et al. The Tohoku journal of experimental medicine (2018)

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