In Oct 2019, a 19-year-old man was admitted to our hospital with liver dysfunction. He has hypersensitivity of skin to sunlight since childhood. Liver function tests demonstrated elevated liver enzymes (alanine aminotransferase, ALT 206U/L,aspartate aminotransferase, AST 81U/L, γ-glutamyl transpeptidase, γ-GT 186U/L, total bilirubin, TBil 19.9 µmol/L, direct bilirubin, DBil 7.6µmol/L). Magnetic resonance imaging indicated liver fibrosis, broadened portal vein, portal hypertension and splenomegaly. Liver puncture pathology revealed significant cholestasis of hepatocytes and bile ducts with liver fibrosis, biliary cast in the capillary bile ducts and activated Kupffer cells presented as malts cross under polarized light, which is protoporphyrin crystal. Blood testing showed zinc protoporphyrin in erythrocyte was 8.8ug/g Hb (normal, 0-4.7). Total protoporphyrin in erythrocytes was not detected. Urinary porphyrin and uroporphyrinogen were negative. The next generation sequencing (NGS) revealed a double heterozygous FECH mutation (c.1156-1G > A, c.315-48T > C) inherited from his parents. Otherwise, blood routine showed that leukocyte count (WBC) was 4.72×109/L with a normal differential count, hemoglobin concentration (Hb) was 137g/L, and platelet count (PLT) was 121×109/L. This patient was diagnosed with congenital erythropoietic protoporphyria with liver fibrosis. Polyunsaturated phosphatidylcholine and diammonium glycyrrhizinate were provided to protect hepatocytes from toxic damage.
In July 2020, the patient was presented with fatigue and low fever for one week. Blood routine displayed Hb of 55g/L, reticulocyte absolute value of 20×109/L, with WBC of 2.24×109/L and PLT of 18×109/L. Bone marrow (BM) punctures of posterior superior iliac spine were performed twice. Both BM aspirate smear showed hypocellularity and trephine biopsy showed overly hypoplasia, cavitas medullaris filled with adipocytes and no megakaryocyte was found (Fig. 1A-C). Chromosomal karyotype was 46, XY  and no gene mutation associated with AML/MPN/MDS was detected by NGS. The results of liver function tests were within normal limits during the period. Ferritin, folic acid and vitamin B12 were not deficient. CMV-DNA, EBV-DNA were negative. Paroxysmal nocturnal hemoglobinuria (PNH) clone was detected by flow cytometry. PNH granulocyte clone sizes were 4% and 2% using the FLEAR and CD59-based assays respectively. PNH erythrocyte clone sizes both were 2% for the CD59 and CD55-based assays respectively. Severe aplastic anemia (AA) with PNH clone was diagnosed.
The patient has no sibling donor to perform hematopoietic stem cell transplantation (HSCT). Liver fibrosis also placed restrictions on allo-transplantation and intensive immunosuppressive treatment of antithymocyte globulin (ATG). He was started on cyclosporin A (CsA, 75mg twice-daily) with a trough concentration of CsA was only 34.7ng/ml. The dosage of CsA increased to 125mg twice-daily and the trough concentration of CsA was just 115.2 ng/ml. Limited by the potential hepatotoxicity, it is difficult to increase the CsA dose. Therefore, we initiated avatrombopag therapy (20mg once-daily). After 5 months, his Hb increased to 123g/L and platelet counts recovered to 103×109/L (Fig. 2A-B). Avatrombopag was reduced to 20mg once every other day for 3 months and then stopped. The patient kept response with a low dose of CsA (75mg twice-daily) and the liver function tests remained stable during the whole course (Fig. 2C-G).
Mild microcytic anemia with low ferritin can be seen in EPP patients though the mechanism of iron deficiency is unclear . But no aplastic anemia has been described. The patient presented pancytopenia at 20 years old without any deformity of body. He had no family history of bone marrow failure disease and no germline gene mutation associated with congenital AA had been detected by next generation sequencing. So, he was diagnosed as acquired AA. The detection of a PNH clone also supported the judgement. T Shirota reported a case of acquired EPP following myelodysplastic syndrome (MDS) with the history of 15-years AA and stem cells defects of the heme biosynthesis in MDS are thought to lead to the development of EPP. But based on our knowledge, this is the first reported case of AA with congenital EPP. Acquired AA is characterized by pancytopenia and bone marrow hypoplasia, which results from immune-mediated hematopoiesis suppression. No immune injury has been assessed in EPP patients.
Most EPP patients manifest as photodermatoses and need sun-protection. But deposition of protoporphyrin crystals in hepatocytes and bile canaliculi causes progressive liver damage in a minority of patients. Some therapeutic approaches have been adopted for liver disease of EPP, such as attempts to induce bile flow by ursodeoxycholic acid, to protect hepatocytes from toxic damage by N-acetyl cysteine, and to interrupt the enterohepatic circulation by cholestyramine . But none of these has been shown to be unequivocally efficacious. And it is also important to avoid alcohol and drugs that harm the liver. EPP patients of end-stage liver disease should considered liver transplantation and even HSCT to prevent recurrence of hepatic disease.
Treatment options for severe AA include HSCT and immunosuppressive therapy (IST) . Both EPP and severe AA can be cured by HSCT. However, liver fibrosis and lack of sibling-donor was hindering him from the transplantation therapy. ATG and the variety of drugs that may be combined also increase the burden on the liver and the risk of infection. Avatrombopag is a thrombopoietin receptor agonists (TPO-RA) that is FDA-approved for immune thrombocytopenia (ITP) and periprocedural thrombocytopenia in patients with chronic liver disease . This is the first case report for its use in severe AA to date. TPO-RA showed beneficial effect on the expansion and maintenance of hematopoietic stem cells. TPO-RA eltrombopag has been used in AA with an overall response rate of 40–50% in patients with refractory severe AA as a single agent and response rates up to 94% in newly diagnosed severe AA together with horse ATG and CsA . Eltrombopag has an adverse event of hepatic impairment. With its advantage of absence of hepatotoxicity, avatrombopag is a favorable option for this patient. Finally, the patient achieved response with two oral drugs of avatrombopag and low-dose CsA sparing HSCT and ATG.
Aplastic anemia with EPP is really rare and maybe a mere coincidence. Liver fibrosis associated with EPP affects the prognosis significantly. TPO-RA avatrombopag combined with CsA provide an available therapy for patients with severe aplastic anemia associated with EPP and liver fibrosis.