case_images: PMC8792439_01
case_images: (A) CT images of the lungs and abdomen on admission, after coenzyme Q10 and riboflavin treatment, and before death. After treatment with riboflavin and coenzyme Q10, the CT value of the patient's liver gradually increased from -40 Hu at the beginning to nearly normal. (B) Homozygous mutation of ETFDH gene (c.250G>A) identified by whole exome sequencing.
case_images: fimmu-12-810677-g001.jpg
case_images: PMC8792439_01_fimmu-12-810677-g001.jpg
case_images: f1
case_images: Both lungs showed large patchy lesions, and the density of the liver was quantitatively measured by CT image as -40 Hu, which was lower than the density of water (0 Hu) and was similar to the density of fat (-40 Hu) ( Figure 1A ). Results of whole exome sequencing revealed a homozygous mutation of ETFDH gene (c.250G>A) as shown in  Figure 1B . There are eight diagnostic criteria for hemophagocytic lymphocytosis, and the patient met six of them, including persistent fever, splenomegaly ( Figure 1A ), cytopenias ( Figure 3 ), increased ferritin (1000 ng/mL, reference range 7-323 ng/mL), hypertriglyceridemia and hypofibrinogenemia ( Table 1  and  Figure 3 ), and hemophagocytosis in the bone marrow ( Figure 2 ).
case_images: Bone marrow smear carried out when hemoglobin was lowest; the arrow indicates hemophagocytic cells.
case_images: fimmu-12-810677-g002.jpg
case_images: PMC8792439_01_fimmu-12-810677-g002.jpg
case_images: f2
case_images: There are eight diagnostic criteria for hemophagocytic lymphocytosis, and the patient met six of them, including persistent fever, splenomegaly ( Figure 1A ), cytopenias ( Figure 3 ), increased ferritin (1000 ng/mL, reference range 7-323 ng/mL), hypertriglyceridemia and hypofibrinogenemia ( Table 1  and  Figure 3 ), and hemophagocytosis in the bone marrow ( Figure 2 ).
case_images: Changes in patient's blood routine, liver function within 42 days after admission. The reference range for each variable are shown in 
  Table 1
  . The amount of red blood cells and platelet administered to the patient are marked with red font on the right side of the corresponding time. HD, hospitalization day; Hb, hemoglobin; PLT, platelets; WBC, white blood cell; ALT, alanine aminotransferase; AST, aspartate aminotransferase; LDH, lactate dehydrogenase; TC, total cholesterol; TG, triglycerides.
case_images: fimmu-12-810677-g003.jpg
case_images: PMC8792439_01_fimmu-12-810677-g003.jpg
case_images: f3
case_images: CT imaging suggested that the patient's liver was improved significantly which was confirmed by laboratory tests ( Figure 3 ). There are eight diagnostic criteria for hemophagocytic lymphocytosis, and the patient met six of them, including persistent fever, splenomegaly ( Figure 1A ), cytopenias ( Figure 3 ), increased ferritin (1000 ng/mL, reference range 7-323 ng/mL), hypertriglyceridemia and hypofibrinogenemia ( Table 1  and  Figure 3 ), and hemophagocytosis in the bone marrow ( Figure 2 ). Her hemoglobin was maintained at 60g/L, and her platelets gradually increased from 9x10^9/L to normal after the day 32 of hospitalization as liver function continued to improve ( Figure 3 ).