Fetal familial hemophagocytic lymphohistiocytosis: a case report and literature review / 中华围产医学杂志

ABSTRACT

Objective:To discuss the clinical characteristics and genetic diagnosis of fetal familial hemophagocytic lymphohistiocytosis (FHL).Methods:Clinical data of a case of fetal FHL from Children's Hospital, Capital Institute of Pediatrics was analyzed, and related FHL cases at home and abroad were retrieved from PubMed, CNKI, and Wanfang databases using terms including "fetus", "neonate", and "familial hemophagocytic lymphohistiocytosis", from the establishment of the database to January 3, 2021, to summarize the characteristics of this disease.Results:This index case was found with fetal splenomegaly, free fluid in the abdominal cavity, and enlargement of the ventricle at 39 +3 weeks of gestation, and presented with fever, tachypnea, hepatosplenomegaly, skin ecchymosis and petechia, and lymphadenectasis after birth. Laboratory examination revealed pancytopenia, abnormal liver function, elevated ferritin and triglyceride, and decreased fibrinogen levels. CD107a excitation experiment showed decreased degranulation function of NK cell (&Delta;CD107a<5%). Hemophagocytosis was observed in the bone marrow smear. Genomic DNA sequence analysis demonstrated compound heterozygous mutations of c.118-308C>T and c.3002T>C in the UNC13D gene. All the above findings led to the diagnosis of FHL3. Despite chemotherapy with dexamethasone and cyclosporin, and symptomatic treatment after admission without hematopoietic stem cell transplantation, the baby died on day 52. A total of 15 papers related to fetal FHL, including 20 infants, were retrieved. Among these 21 cases (including the index case), the main clinical symptoms were fetal edema and hepatosplenomegaly, which may be accompanied by fetal distress and increased amniotic fluid volume, and postnatal fever, dyspnea, rash, and central nervous system involvement. Laboratory and imaging examination results were consistent with the diagnostic criteria for hemophagocytic hyperplasia. As far as we know, the reported fetal FHL gene mutations were PRF1 (FHL2) and UNC13D gene mutation (FHL3), in which reduced expression of perforin and granzyme can be detected, respectively. Dexamethasone, cyclosporin, etoposide, and other chemotherapy and symptomatic treatment are the primary treatments currently, and alternative therapies include intrauterine chemotherapy in the third trimester and postnatal hematopoietic stem cell transplantation. Among the 21 cases, including the index case, intrauterine death occurred in four cases, 13 children died at different times after birth, and only four children survived, among which the eldest one was 12 years old. Conclusions:FHL is a condition with atypical early signs, high mortality rate and treatment difficulties. Fetal FHL should be considered in differential diagnosis in fetuses with edema or hepatosplenomegaly besides hemolysis, infection, autoimmune diseases, and hereditary problems. Therefore, with immunotechnology and gene sequencing, early diagnosis and treatment can be prompted to improve the prognosis of this group of population.