A Case Report of Pregnancy Complicated with Primary Hemophagocytic Lymphohistiocytosis

Background: Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome characterized by excessive activation of NK cells and cytotoxic T lymphocytes, subsequently leading to macrophage activation and increased cytokine production. Misdiagnosis due to nonspecific clinical presentations and inadequate understanding of the disease can significantly jeopardize the safety of both the mother and the infant. We report a case of pregnancy combined with HLH and conduct a literature review to provide insights into the diagnosis and treatment of pregnancy -related HLH. Case Presentation: We discussed a case of a pregnant woman with persistent postpartum fever, serum ferritin, and elevated liver function, who failed to respond to repeated anti -infective therapy and was diagnosed with HLH after multidisciplinary diagnostic treatment. We gave dexamethasone treatment, and the patient's temperature and blood cells quickly returned to normal. Finally, exome sequencing revealed heterozygous variation in UNC13D gene, so we considered this case as pregnancy combined with primary HLH (pHLH). Conclusion: We report the case of HLH diagnosed during pregnancy and show that early diagnosis and timely intervention can prevent rapid disease progression, reduce maternal mortality rates, and improve survival rates. Additionally, molecular genetic testing can confirm pathogenic gene mutations, providing essential genetic counseling for patients with pHLH who plan to conceive a healthy child.