Curative bone marrow transplantation in erythropoietic protoporphyria after reversal of severe cholestasis

Liver transplantation and primary liver cancer in porphyria

The porphyrias are a heterogeneous group of metabolic disorders that result from defects in heme synthesis. The metabolic defects are present in all cells, but symptoms are mainly cutaneous or related to neuropathy. The porphyrias are highly relevant to hepatologists since patients can present with symptoms and complications that require liver transplantation (LT), and some porphyrias are associated with a high risk for primary liver cancer (PLC). Among the cutaneous porphyrias, erythropoietic protoporphyria (EPP) can lead to cholestatic liver failure where LT cures the liver disease but not the porphyria. In acute porphyria (AP), neurotoxic porphyrin precursors are produced in the liver and LT is a curative treatment option in patients with recurrent severe neuropathic attacks. Patients with AP, mainly acute intermittent porphyria, have a significantly increased risk for PLC that warrants surveillance and adequate follow-up of high-risk groups. LT is well established in both EPP with liver failure and AP with recurrent attacks, but most transplant centres have little porphyria experience and cooperation between transplant hepatologists, and porphyria experts is important in the often-difficult decisions on timing and management of comorbid conditions.

Consecutive Liver and Bone Marrow Transplantation for Erythropoietic Protoporphyria: Case Report and Literature Review

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare inherited disease of heme biosynthesis resulting in the accumulation of protoporphyrin, characterized by liver failure in a minority of cases. Although liver transplant (LT) is the therapeutic strategy for advanced hepatic disease, it does not correct the primary defect, which leads to recurrence in liver graft. Thus, hematopoietic stem cell transplantation (HSCT) is an approach for treating EPP.

METHODS

We aim to describe the first sequential LT and HSCT for EPP performed in Latin America, besides reviewing the present-day literature.

RESULTS

The patient, a 13-year-old female with a history of photosensitivity, presented with symptoms of cholestatic and hepatopulmonary syndrome and was diagnosed with EPP. Liver biopsy demonstrated cirrhosis. She was submitted to a successful LT and showed improvement of respiratory symptoms. However, she had disease recurrence on the liver graft. She underwent a myeloablative HSCT using a matched unrelated donor, conditioning with BuCy (busulfan and cyclophosphamide), and GvHD (graft vs. host disease) prophylaxis with ATG (thymoglobulin), tacrolimus and methotrexate. Neutrophil engraftment occurred on D+18. She has presented mixed chimerism, but normalization of PP levels, being 300 days after HSCT, in good state of health and normal liver function.

CONCLUSIONS

Consecutive LT and HSCT for EPP is a procedure that has been described in 10 cases in the literature and, even though these patients are a highly diversified population, studies have shown favorable results. This concept of treatment should be considered in patients with established liver disease.

Ferrochelatase: Mapping the Intersection of Iron and Porphyrin Metabolism in the Mitochondria

Porphyrin and iron are ubiquitous and essential for sustaining life in virtually all living organisms. Unlike iron, which exists in many forms, porphyrin macrocycles are mostly functional as metal complexes. The iron-containing porphyrin, heme, serves as a prosthetic group in a wide array of metabolic pathways; including respiratory cytochromes, hemoglobin, cytochrome P450s, catalases, and other hemoproteins. Despite playing crucial roles in many biological processes, heme, iron, and porphyrin intermediates are potentially cytotoxic. Thus, the intersection of porphyrin and iron metabolism at heme synthesis, and intracellular trafficking of heme and its porphyrin precursors are tightly regulated processes. In this review, we discuss recent advances in understanding the physiological dynamics of eukaryotic ferrochelatase, a mitochondrially localized metalloenzyme. Ferrochelatase catalyzes the terminal step of heme biosynthesis, the insertion of ferrous iron into protoporphyrin IX to produce heme. In most eukaryotes, except plants, ferrochelatase is localized to the mitochondrial matrix, where substrates are delivered and heme is synthesized for trafficking to multiple cellular locales. Herein, we delve into the structural and functional features of ferrochelatase, as well as its metabolic regulation in the mitochondria. We discuss the regulation of ferrochelatase via post-translational modifications, transportation of substrates and product across the mitochondrial membrane, protein-protein interactions, inhibition by small-molecule inhibitors, and ferrochelatase in protozoal parasites. Overall, this review presents insight on mitochondrial heme homeostasis from the perspective of ferrochelatase.

Recognized and Emerging Features of Erythropoietic and X-Linked Protoporphyria

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inherited disorders resulting from defects in two different enzymes of the heme biosynthetic pathway, i.e., ferrochelatase (FECH) and delta-aminolevulinic acid synthase-2 (ALAS2), respectively. The ubiquitous FECH catalyzes the insertion of iron into the protoporphyrin ring to generate the final product, heme. After hemoglobinization, FECH can utilize other metals like zinc to bind the remainder of the protoporphyrin molecules, leading to the formation of zinc protoporphyrin. Therefore, FECH deficiency in EPP limits the formation of both heme and zinc protoporphyrin molecules. The erythroid-specific ALAS2 catalyses the synthesis of delta-aminolevulinic acid (ALA), from the union of glycine and succinyl-coenzyme A, in the first step of the pathway in the erythron. In XLP, ALAS2 activity increases, resulting in the amplified formation of ALA, and iron becomes the rate-limiting factor for heme synthesis in the erythroid tissue. Both EPP and XLP lead to the systemic accumulation of protoporphyrin IX (PPIX) in blood, erythrocytes, and tissues causing the major symptom of cutaneous photosensitivity and several other less recognized signs that need to be considered. Although significant advances have been made in our understanding of EPP and XLP in recent years, a complete understanding of the factors governing the variability in clinical expression and the severity (progression) of the disease remains elusive. The present review provides an overview of both well-established facts and the latest findings regarding these rare diseases.

Sequential paternal haploidentical donor liver and HSCT in EPP allow discontinuation of immunosuppression post-organ transplant

BACKGROUND

EPP is characterized by photosensitivity and by liver disease. When LT is performed in EPP, recurrence often occurs in the allograft due to ongoing protoporphyrin production in bone marrow. Therefore, curative treatment requires allogeneic HSCT after LT. Long-term immunosuppression could be spared by using the same donor for both transplants.

METHODS

A 2-year-old girl with EPP in liver failure underwent liver transplant from her father. Transfusion and apheresis therapy were used to lower protoporphyrin levels before and after liver transplant. Ten weeks after liver transplant, she underwent HSCT, using the same donor. Conditioning was with treosulfan, fludarabine, cyclophosphamide, and ATG. GVHD prophylaxis was with abatacept, methotrexate, MMF, and tacrolimus. We followed the patient's erythrocyte protoporphyrin and liver and skin health for 2 years after transplant.

RESULTS

After hematopoietic stem cell engraftment, a decline in protoporphyrin levels was observed, with clinical resolution of photosensitivity. Liver biopsies showed no evidence of EPP. Mild ACR occurred and responded to steroid pulse. Two years post-HSCT, the patient has been weaned off all immunosuppression and remains GVHD and liver rejection free.

CONCLUSIONS

Sequential liver and HSCT from the same haploidentical donor are feasible in EPP. This strategy can allow for discontinuation of immune suppression.

Hematopoietic cell transplant for reversal of liver fibrosis in a pediatric patient with erythropoietic protoporphyria

BACKGROUND

EPP is a rare disorder of heme biosynthesis in which patients present with disabling photosensitivity. A subset of patients develop severe liver disease with progressive liver failure necessitating an OLT. A HCT can potentially cure EPP by replacing the native bone marrow, which is the primary site of heme synthesis. However, due to concerns for inherent risks of treatment-related toxicities, the use of HCT has been reserved for patients undergoing an OLT to avoid disease recurrence in the hepatic graft. Data for HCT in EPP are lacking, particularly in the pediatric population.

CASE (METHODS/RESULTS)

We present the case of a 12-year-old patient with EPP photosensitivity and cirrhosis, whom we successfully treated with pre-emptive allogeneic HCT, significantly improving the patient's quality of life. We used a matched-unrelated donor bone marrow-derived graft. Our patient achieved full donor peripheral blood chimerism and has not had any evidence of GVHD. In addition to resolution of photosensitivity, our patient had reversal of liver fibrosis which we feel was largely due to intervention at an early stage of compensated cirrhosis.

CONCLUSION

Our case highlights the successful application of a known RIC regimen to this rare disorder that was well tolerated with sustained donor engraftment. It also emphasizes the importance of timing for HCT in patients with EPP and liver fibrosis. HCT should be considered early in pediatric patients with EPP-hepatopathy to prevent progression to liver failure and need for OLT with lifelong immunosuppression.

Successful Liver Transplantation for Liver Failure With Erythropoietic Protoporphyria by Covering the Operating Theater Lights With Polyimide Film: A Case Report

BACKGROUND

Erythropoietic protoporphyria is a rare disease of heme biosynthesis resulting in excessive accumulation of protoporphyrin in various organs. The most typical symptom is photosensitivity caused by activated protoporphyrins (wavelength ~400 nm). Accumulated protoporphyrin in the liver also causes liver failure, and liver transplantation is the only life-saving treatment. Phototoxic injury to abdominal organs has been reported during liver transplantation. Thus, to avoid phototoxic injury during liver transplantation, it has previously been conducted with only shadowless lights and ceiling lights off in the operating theater. Here, we report a case of a safe and successful liver transplantation in a patient with erythropoietic protoporphyria where the operating theater lights were covered with polyimide film.

CASE PRESENTATION

A 50-year-old man presented with hepatic failure owing to erythropoietic protoporphyria. Before liver transplantation, the shadowless lights and ceiling lights in the operating theater were covered entirely with polyimide film. This filter completely blocked the harmful wavelength of light (400-470 nm). Orthotopic liver transplantation was safely and successfully performed with adequate illumination and patient monitoring. The patient followed a normal postoperative course without phototoxic injuries or protoporphyrin re-accumulation.

CONCLUSION

Covering not only shadowless lights but also all ceiling lights in the operating theater with the polyimide film allowed safe surgery, safe anesthesia, and safe monitoring of the patient who underwent liver transplantation for severe liver failure owing to erythropoietic protoporphyria.

Erythropoietic Protoporphyria and X-Linked Protoporphyria: pathophysiology, genetics, clinical manifestations, and management

Erythropoietic Protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare, genetic photodermatoses resulting from defects in enzymes of the heme-biosynthetic pathway. EPP results from the partial deficiency of ferrochelatase, and XLP results from gain-of-function mutations in erythroid specific ALAS2. Both disorders result in the accumulation of erythrocyte protoporphyrin, which is released in the plasma and taken up by the liver and vascular endothelium. The accumulated protoporphyrin is activated by sunlight exposure, generating singlet oxygen radical reactions leading to tissue damage and excruciating pain. About 2-5% of patients develop clinically significant liver dysfunction due to protoporphyrin deposition in bile and/or hepatocytes which can advance to cholestatic liver failure requiring transplantation. Clinically these patients present with acute, severe, non-blistering phototoxicity within minutes of sun-exposure. Anemia is seen in about 47% of patients and about 27% of patients will develop abnormal serum aminotransferases. The diagnosis of EPP and XLP is made by detection of markedly increased erythrocyte protoporphyrin levels with a predominance of metal-free protoporphyrin. Genetic testing by sequencing the FECH or ALAS2 gene confirms the diagnosis. Treatment is limited to sun-protection and there are no currently available FDA-approved therapies for these disorders. Afamelanotide, a synthetic analogue of α-melanocyte stimulating hormone was found to increase pain-free sun exposure and improve quality of life in adults with EPP. It has been approved for use in the European Union since 2014 and is not available in the U.S. In addition to the development of effective therapeutics, future studies are needed to establish the role of iron and the risks related to the development of hepatopathy in these patients.

Management of Patients With Erythropoietic Protoporphyria-Related Progressive Liver Disease

Erythropoietic protoporphyria (EPP) is an inherited metabolic disorder of heme synthesis resulting from overproduction of protoporphyrin IX (PPIX), which can lead to progressive liver disease characterized by recurrent EPP crises and end-stage liver disease. We used the Australian Transplant Registry to identify 5 patients referred for liver transplantation between 2008 and 2017. A total of 4 patients had EPP secondary to ferrochelatase deficiency, and 1 patient had X-linked EPP. No patient had follow-up with a specialist prior to the diagnosis of progressive liver disease. There were 3 patients who underwent orthotopic liver transplantation, whereas 2 died while on the transplant waiting list. Parenteral PPIX-lowering therapy was used in 4 patients and was effective in 3 patients, although 2 of these had rebound porphyria and worsening liver function following a decrease in the intensity of therapy. Early disease recurrence in the allograft following transplantation occurred in 2 patients requiring red cell exchange (RCE) to successfully attain and maintain low PPIX levels, but RCE was associated with hemosiderosis in 1 patient. Allogeneic stem cell transplantation (AlloSCT) was performed in 2 patients. One failed engraftment twice, whereas the second rejected the first graft but achieved full donor chimerism with a second graft and increased immunosuppression. In conclusion, our observations suggest that progressive liver disease needs parenteral PPIX-lowering treatment with the intensity adjusted to achieve a target Erc-PPIX level. Because EPP liver disease is universally recurrent, AlloSCT should be considered in all patients with adequate immunosuppression to facilitate engraftment. RCE appears to be effective for recurrent EPP liver disease but is associated with an increased risk of iron overload.

Clinical Guide and Update on Porphyrias

Physicians should be aware of porphyrias, which could be responsible for unexplained gastrointestinal, neurologic, or skin disorders. Despite their relative rarity and complexity, most porphyrias can be easily defined and diagnosed. They are caused by well-characterized enzyme defects in the complex heme biosynthetic pathway and are divided into categories of acute vs non-acute or hepatic vs erythropoietic porphyrias. Acute hepatic porphyrias (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and aminolevulinic acid dehydratase deficient porphyria) manifest in attacks and are characterized by overproduction of porphyrin precursors, producing often serious abdominal, psychiatric, neurologic, or cardiovascular symptoms. Patients with variegate porphyria and hereditary coproporphyria can present with skin photosensitivity. Diagnosis relies on measurement of increased urinary 5-aminolevulinic acid (in patients with aminolevulinic acid dehydratase deficient porphyria) or increased 5-aminolevulinic acid and porphobilinogen (in patients with other acute porphyrias). Management of attacks requires intensive care, strict avoidance of porphyrinogenic drugs and other precipitating factors, caloric support, and often heme therapy. The non-acute porphyrias are porphyria cutanea tarda, erythropoietic protoporphyria, X-linked protoporphyria, and the rare congenital erythropoietic porphyria. They lead to the accumulation of porphyrins that cause skin photosensitivity and occasionally severe liver damage. Secondary elevated urinary or blood porphyrins can occur in patients without porphyria, for example, in liver diseases, or iron deficiency. Increases in porphyrin precursors and porphyrins are also found in patients with lead intoxication. Patients with porphyria cutanea tarda benefit from iron depletion, hydroxychloroquine therapy, and, if applicable, elimination of the hepatitis C virus. An α-melanocyte-stimulating hormone analogue can reduce sunlight sensitivity in patients with erythropoietic protoporphyria or X-linked protoporphyria. Strategies to address dysregulated or dysfunctional steps within the heme biosynthetic pathway are in development.

The Outcome of Allogeneic Hematopoietic Stem Cell Transplantation for Inherited Diseases Is Influenced by HLA Match, Year of Transplantation, and Immunized Female Donor

BACKGROUND

For many inborn errors of metabolism (IEM), allogeneic hematopoietic stem cell transplantation (HSCT) is the only cure.

METHODS

We report the outcome in 160 patients with inherited diseases, who were treated with HSCT in 3 decades. Median age was 3 years (range 0.1-63). Grafts were from matched related donors (MRDs, 56), matched unrelated donors (MUDs, 66), or HLA-mismatched donors (38).

RESULTS

Graft failure (GF) occurred in 26 patients (16%), severe acute graft-versus-host disease (GVHD) in 9 (6%), and chronic GVHD in 23 (12%). Ten-year survival was 64% before the year 2000 and 86% after that (P = 0.01). Ten-year survival for MRD grafts was 90%, as opposed to 79% for MUD grafts and 56% for HLA-mismatched grafts (P = 0.03). In multivariate analysis, GF was associated with having an HLA-mismatched donor (P < 0.05) or MUD (P = 0.015) and with reduced-intensity conditioning (P < 0.01). Death was associated with year of transplant (P = 0.015), having an HLA-mismatched donor (P < 0.001), and being a male recipient from an immune female donor (P = 0.05).

CONCLUSIONS

The outcome after HSCT for IEM depends on HLA match, year and immune female donor.

Cimetidine/lactulose therapy ameliorates erythropoietic protoporphyria-related liver injury

A 21-year-old Japanese man was admitted to our hospital because of severe abdominal pain and jaundice. He had been suffering from abdominal pain attacks and liver dysfunction since 18 years of age. Liver histology showed amorphous brown deposits in the sinusoidal space and significant periportal fibrosis without apparent hepatitis. Increased protoporphyrin in serum and feces and ferrochelatase gene mutation confirmed the final diagnosis of erythropoietic protoporphyria (EPP). Since ursodeoxycholic acid (UDCA) intake and glucose infusion are insufficient to ameliorate jaundice and abdominal attacks, cimetidine and lactulose were added in order to suppress hepatic delta-aminolevulinic acid synthase and limit re-absorption of protoporphyrin, respectively. Afterwards, the jaundice, liver dysfunction and abdominal symptoms improved and UDCA, cimetidine, and lactulose administration was continued. A repeat biopsy at 1.5 years after adding cimetidine/lactulose revealed marked attenuation of periportal fibrosis and protoporphyrin deposits. As far as we know, this is the first demonstration of histological improvement of EPP-induced liver abnormalities due to persistent cimetidine/lactulose administration. These treatments may be useful for EPP-related liver injury.

Modeling the ferrochelatase c.315-48C modifier mutation for erythropoietic protoporphyria (EPP) in mice

Erythropoietic protoporphyria (EPP) is caused by deficiency of ferrochelatase (FECH), which incorporates iron into protoporphyrin IX (PPIX) to form heme. Excitation of accumulated PPIX by light generates oxygen radicals that evoke excessive pain and, after longer light exposure, cause ulcerations in exposed skin areas of individuals with EPP. Moreover, ∼5% of the patients develop a liver dysfunction as a result of PPIX accumulation. Most patients (∼97%) have a severe FECH mutation (Mut) in trans to an intronic polymorphism (c.315-48C), which reduces ferrochelatase synthesis by stimulating the use of an aberrant 3′ splice site 63 nt upstream of the normal site for exon 4. In contrast, with the predominant c.315-48T allele, the correct splice site is mostly used, and individuals with a T/Mut genotype do not develop EPP symptoms. Thus, the C allele is a potential target for therapeutic approaches that modify this splicing decision. To provide a model for pre-clinical studies of such approaches, we engineered a mouse containing a partly humanized Fech gene with the c.315-48C polymorphism. F1 hybrids obtained by crossing these mice with another inbred line carrying a severe Fech mutation (named m1Pas) show a very strong EPP phenotype that includes elevated PPIX in the blood, enlargement of liver and spleen, anemia, as well as strong pain reactions and skin lesions after a short period of light exposure. In addition to the expected use of the aberrant splice site, the mice also show a strong skipping of the partly humanized exon 3. This will limit the use of this model for certain applications and illustrates that engineering of a hybrid gene may have unforeseeable consequences on its splicing.

Summary: A new mouse model reproduces the predominant genetic disposition of patients affected by erythropoietic protoporphyria, a rare disease associated with extreme pain after light exposure.

Bone marrow transplant for X-linked protoporphyria with severe hepatic fibrosis

XLP is an erythroid porphyria that results in variable cutaneous photosensitivity due to accumulation of protoporphyrin. The genetic defect in XLP is mutation of the gene ALAS2, resulting in gain of function for the erythroid enzyme 5-aminolevulinate synthase 2. Previous reports have shown that protoporphyrin-induced liver disease may also occur in XLP, occasionally severe enough to warrant liver transplantation; however, transplantation may be followed by injury to the graft due to continued presence of the underlying metabolic disorder in the bone marrow. We present a case of XLP with severe liver disease successfully treated with HPCT to avoid liver transplantation. The case also demonstrates the feasibility of reduced intensity transplant to provide engraftment sufficient for correction of porphyria and tolerability of reduced intensity conditioning containing TLI in the face of severe liver injury.

Liver transplantation in the management of porphyria

Porphyrias are a group of eight metabolic disorders, each resulting from a mutation that affects an enzyme of the heme biosynthetic pathway. Porphyrias are classified as hepatic or erythropoietic, depending upon the site where the gene defect is predominantly expressed. Clinical phenotypes are classified as follows: (1) acute porphyrias with neurovisceral symptoms: acute intermittent porphyria; delta amino-levulinic acid hydratase deficiency porphyria; hereditary coproporphyria; and variegate porphyria and (2) cutaneous porphyrias with skin blistering and photosensitivity: porphyria cutanea tarda; congenital erythropoietic porphyria; hepatoerythropoietic porphyria and both erythropoietic protoporphyrias: autosomal dominant and X-linked. Liver transplantation (LT) may be needed for recurrent and/or life-threatening acute attack in acute intermittent porphyria or acute liver failure or end-stage chronic liver disease in erythropoietic protoporphyria. LT in acute intermittent porphyria is curative. Erythropoietic protoporphyria patients needing LT should be considered for bone marrow transplantation to achieve cure.

CONCLUSION

This article provides an overview of porphyria with diagnostic approaches and management strategies for specific porphyrias and recommendations for LT with indications, pretransplant evaluation, and posttransplant management.

A second attack of cholestasis associated with erythropoietic protoporphyria was successfully treated by plasma exchange and blood transfusion

Erythropoietic protoporphyria (EPP) is a rare hereditary disease that can sometimes cause acute liver failure based on cholestasis. Acute liver failure is a fatal complication and is associated with EPP in 1-4 % of patients. Although it is extremely difficult to recover from acute liver failure, we experienced an important case of EPP where the patient recovered from the first attack of cholestasis with antibiotic treatment. The patient recovered from a second attack of cholestasis with blood infusion and plasma transfusion. This case suggests that the supply of heme by blood transfusion and the elimination of excess protoporphyrin production by plasma exchange may be a useful treatment for patients with acute cholestasis associated with EPP.

Cutaneous porphyrias part II: treatment strategies

The porphyrias are diverse in pathophysiology, clinical presentation, severity, and prognosis, presenting a diagnostic and therapeutic challenge. Although not easily curable, the dermatological manifestations of these diseases, photosensitivity and associated cutaneous pathology, can be effectively prevented and managed. Sun avoidance is essential, and patient education regarding the irreversibility of photocutaneous damage is a necessary corollary. Beyond preventative measures, the care of fragile, vulnerable skin, and pain management, each of the porphyrias has a limited number of unique additional therapeutic options. Many of the treatments have been published only in small case series or anecdotal reports and do not have well-understood nor proven mechanisms of action. This article presents a comprehensive review of available therapeutic options and long-term management recommendations for the cutaneous porphyrias.

Liver transplantation for acute-on-chronic liver failure from erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disorder of the heme metabolic pathway that is characterized by accumulation of protoporphyrin in the blood, erythrocytes, and tissues, and cutaneous manifestations of photosensitivity, all resulting from abnormalities in ferrochelatase (FECH) activity due to mutations in the FECH gene. Protoporphyrin is excreted by the liver, and excess protoporphyrin leads to cholelithiasis with obstructive episodes and chronic liver disease, finally progressing to liver cirrhosis. Patients with end-stage EPP-associated liver disease require liver transplantation. We describe here a 31-year-old male patient with EPP who experienced acute-on-chronic liver failure and underwent deceased-donor liver transplantation. Surgical and postoperative care included specific shielding from exposure to ultraviolet radiation to prevent photosensitivity-associated adverse effects. The patient recovered uneventfully and was doing well 24 months after transplantation. Future prevention and treatment of liver disease are discussed in detail.

Plasma and red cell exchange transfusions for erythropoietic protoporphyria: a case report and review of the literature

Erythropoietic protoporphyria (EPP) is a rare and usually autosomal dominant disorder characterized by ferrochelatase deficiency and accumulation of protoporphyrin in red blood cells (RBCs), skin, and liver. A small minority of patients develop severe liver dysfunction for which optimum treatment is lacking. Therapeutic plasma exchange (TPE) and RBC exchange (RCE) have been anecdotally reported to benefit patients with EPP and liver failure. A 50-year-old female with EPP developed severe liver dysfunction after knee replacement surgery and high-dose acetaminophen use. Liver biopsy showed cholestatic liver injury without fibrosis. A total of 20 TPE procedures, six RCE procedures, and then 14 more TPE procedures were performed as adjunctive therapy with the purpose of preventing progression to end-stage liver failure. After initial TPE, the plasma and RBC protoporphyrin levels decreased from 834.9 to 180.4 μg/dL (normal, ≤1 μg/dL), and from 3,905 to 2,879 μg/dL (normal, ≤80 μg/dL), respectively, without liver function improvement. RCE decreased RBC protoporphyrin levels from 2,879 to 1,225 μg/dL but plasma protoporphyrin increased from 180.4 to 1,044.1 μg/dL, and liver function failed to improve. Additional TPE again stabilized plasma protoporphyrin and improved RBC protoporphyrin levels but the patient ultimately died owing to end-stage liver disease complications. This case illustrates that TPE and RCE may improve the plasma and RBC biochemical markers of EPP activity but liver function abnormalities may persist and patients may still progress to liver failure either because of irreversible liver injury or independent pathobiological factors unrelated to EPP-induced hepatotoxicity.

New developments in erythropoietic porphyrias

In recent years, important advances have been made in our understanding of the genetics of porphyrias, particularly with respect to erythropoietic protoporphyria (EPP) and congenital erythropoietic porphyria (CEP), 2 forms of erythropoietic porphyria no longer considered to be monogenic. The identification of mutations in genes not previously associated with these disorders as causative factors or modulators of severity has helped to explain the presence of genotypic and phenotypic differences between patients carrying the same mutations. These advances have also led to the identification of causative genetic defects in patients who, based on molecular studies, had no mutations in the uroporphyrinogen III synthase gene UROS (in CEP) or in the ferrochelatase gene FECH (in EPP). Better understanding and characterization of the genetics of porphyrias will allow us to determine genotypic and phenotypic correlations and improve the molecular classification of these diseases, which will have both practical and prognostic implications.

Liver transplantation for erythropoietic protoporphyria in Europe

Liver transplantation is an established lifesaving treatment for patients with severe protoporphyric liver disease, but disease recurrence in the graft occurs for the majority of recipients. Severe burn injuries may occur when protective light filters are not used with surgical luminaires. Motor neuropathy with an unclear pathogenesis is a frequent complication. We retrospectively studied 35 transplants performed for protoporphyric liver disease in 31 European patients between 1983 and 2008. Most of the patients were male (61.3%), and the mean age at the time of primary transplantation was 39 years (range = 9-60 years). The overall patient survival rates were 77% at 1 year and 66% at 5 and 10 years. The overall rate of disease recurrence in the graft was 69%. Forty-three percent of the patients experienced recurrence within a year, but this was often a transient finding that was associated with other graft complications. Phototoxic injuries due to surgical luminaires were seen in 25.0% of the patients who were not protected by filters, but these injuries were not seen in the 9 patients who were protected by filters. Significant motor neuropathies requiring prolonged ventilation complicated the postoperative course for 5 of the 31 patients (16.1%). Hematopoietic stem cell transplantation was performed for 3 patients to prevent graft loss due to disease recurrence. Prognostic markers are needed to identify patients prone to severe protoporphyric liver disease so that curative stem cell transplantation can be offered to select patients instead of liver transplantation.

Treatment options in acute porphyria, porphyria cutanea tarda, and erythropoietic protoporphyria

The porphyrias are a group of uncommon metabolic diseases caused by enzyme deficiencies within heme biosynthesis that lead to neurotoxic or phototoxic heme precursor accumulation. There are four acute porphyrias characterized by neuropsychiatric symptoms: acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and 5-aminolevulinic acid dehydratase deficiency porphyria. Treatment includes elimination of any porphyrogenic factor and symptomatic treatment. Carbohydrate and intravenous heme administration constitute specific therapies in the disorders' acute phase. The mainstay treatment in the cutaneous porphyrias is avoidance of sunlight exposure. In porphyria cutanea tarda and the two acute porphyrias with skin manifestations, variegate porphyria and hereditary coproporphyria, care of the vulnerable skin is important. In porphyria cutanea tarda, specific treatment is accomplished by a series of phlebotomies and/or by low-dose chloroquine administration. In erythropoietic protoporphyria, light-protective beta-carotene is prescribed.

Neonatal bone marrow transplantation prevents liver disease in a murine model of erythropoietic protoporphyria

BACKGROUND & AIMS

Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by partial ferrochelatase deficiency, resulting in protoporphyrin IX (PPIX) accumulation in erythrocytes, responsible for skin photosensitivity. In some EPP patients, the development of cholestatic liver injury due to PPIX accumulation can lead to hepatic failure. In adult EPP mice, bone marrow transplantation (BMT) leads to skin photosensitivity correction but fails to reverse liver damages, probably because of the irreversible nature of liver fibrosis. Our aim was to determine the time course of liver disease progression in EPP mice and to evaluate the protective effect of BMT into neonates.

METHODS

We studied the development of liver disease from birth in EPP mice, in relation with erythroid and hepatic PPIX accumulation. To prevent the development of liver disease, BMT was performed into newborn mice using a novel busulfan-mediated preconditioning assay.

RESULTS

We showed that hepatic PPIX accumulates during the first 2 weeks and correlates with the onset of a progressive liver fibrosis in 12-day-old EPP mice. Transplantation of normal congenic hematopoietic stem cells into EPP neonates led to long-term donor hematopoiesis recovery. A full correction of erythroid PPIX accumulation and skin photosensitivity was obtained. Furthermore, five months after neonatal BMT, liver damage was almost completely prevented.

CONCLUSIONS

We demonstrated for the first time that BMT could be successfully used to prevent liver disease in EPP mice and suggested that BMT would be an attractive therapeutic option to prevent severe liver dysfunction in EPP patients.

UK experience of liver transplantation for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is characterised by excess production of free protoporphyrin from the bone marrow, most commonly due to deficiency of the enzyme ferrochelatase. Excess protoporphyrin gives rise to the cutaneous photosensitivity characteristic of the disease, and in a minority of patients leads to end-stage liver disease necessitating liver transplantation (LT). There is limited information regarding the timing, impact and long-term outcome of LT in such patients, thus we aimed to identify the indications and outcomes of all transplants performed for EPP in the UK using data from the UK Transplant Registry. Between 1987 and 2009, five patients underwent LT for EPP liver disease. Median follow-up was 60 months, and there were two deaths at 44 and 95 months from causes unrelated to liver disease. The remaining recipients are alive at 22.4 years, 61 months and 55 months after transplant. A high rate of postoperative biliary stricturing requiring multiple biliary interventions was observed. Recurrent EPP-liver disease occurred in 4/5 (80%) of patients but graft failure has not been observed. Given the role of biliary obstruction in inducing EPP-mediated liver damage, we suggest that consideration should be given for construction of a Roux loop at the time of transplant. Thus we demonstrate that although EPP liver transplant recipients have a good long-term survival, comparable to patients undergoing LT for other indications, biliary complications and disease recurrence are almost universal, and bone marrow transplantation should be considered where possible.

Erythropoietic protoporphyria in Sweden: demographic, clinical, biochemical and genetic characteristics

OBJECTIVE

To investigate the demographic, clinical, biochemical and genotypic features of patients with erythropoietic protoporphyria (EPP) in a Swedish cohort.

DESIGN

Cross-sectional questionnaire, biochemical and genetic study.

SETTING

Sweden.

SUBJECTS

Fifty-one Swedish individuals known in 2008 to have EPP confirmed by molecular diagnosis. There were no exclusion criteria; all patients were included in the demographic and genetic study. A total of 92% participants completed the questionnaire study and 82% the biochemical study.

RESULTS

The prevalence of EPP was 1 : 180,000. Nine novel ferrochelatase gene mutations were found. The most commonly reported age at onset of symptoms was the first year of life and the mean age at diagnosis was 22 years. Painful photosensitivity was the main symptom. Exogenous factors other than sunlight were frequently reported to cause cutaneous symptoms. One in five patients reported a positive effect of beta-carotene therapy. A marked impact of EPP on quality of life was reported. Women had a significantly lower mean erythrocyte protoporphyrin concentration than men. Of all participants, 84% had insufficient vitamin D concentrations, 44% had below normal serum ferritin or transferrin saturation levels and red cell abnormalities were common.

CONCLUSIONS

The notably delayed diagnosis suggests the need for an increased awareness of EPP. Disturbed erythropoiesis, biochemical signs of iron deficiency and low vitamin D levels are frequent findings in this disease. New and better treatments are needed as current treatment options for symptom amelioration are limited. Vitamin D supplementation should be considered.

Vitamin D deficiency in patients with erythropoietic protoporphyria

BACKGROUND

The main symptom of patients with erythropoietic protoporphyria (EPP) is painful photosensitivity, starting within minutes of sun exposure and leading to sun-avoidance. As 80-100% of vitamin D is synthesized under the influence of sunlight, we investigated whether the avoidance of sunlight exposure in the Dutch EPP patient population causes vitamin D deficiency. Furthermore, we studied the relation between vitamin D levels, total erythrocyte protoporphyrin and quality of life.

METHODS

In a cross-sectional study of 48 Dutch EPP patients (mean age 41.4 years; range 16-77; 23 male, 25 female), we assessed serum 25-hydroxyvitamin D (25(OH)D) levels between June and November 2007, as well as total erythrocyte protoporphyrin (TEP) levels and Dermatology Life Quality Index (DLQI) scores.

RESULTS

Mean serum 25(OH)D was 66 nmol/L (range 18-140, quartiles 36, 87). Twenty-two patients (46%; 15 male, 7 female) were vitamin D deficient. There was a significant difference (p = 0.029) in mean serum 25(OH)D between female (mean 75 nmol/L, range 18-140) and male patients (mean 55 nmol/L, range 18-115). The level of serum 25(OH)D showed a negative correlation with total erythrocyte protoporphyrin (TEP) (Pearson rank correlation (r(p)) = -0.337; p = 0.034). Serum 25(OH)D was inversely associated with scores of the Dermatology Life Quality Index (DLQI) (Spearman's rho correlation (r(s)) = -0.486; p = 0.001).

CONCLUSIONS

The prevalence of vitamin D deficiency is high in the Dutch EPP population, especially in male patients, and correlates with the severity of EPP. Screening for and treatment of vitamin D deficiency should therefore be implemented in the care of these patients.

Delayed immune recovery following sequential orthotopic liver transplantation and haploidentical stem cell transplantation in erythropoietic protoporphyria

A nine-yr-old boy with EPP suffered from severe skin burns and liver failure caused by progressive cholestasis and fibrosis. OLT was performed without major complications. Four months following liver transplantation he underwent parental haploidentical HSCT. The myeloablative conditioning regimen was relatively well tolerated and hematological engraftment was rapid (on day 10). Protoporphyrin concentrations returned to normal following HSCT. However, immune recovery was significantly delayed. Varicella zoster virus reactivation resulted in impaired vision, prolonged hospitalization and eventually in multiorgan failure and death. Sequential liver and haploidentical HSCT proved feasible though a high risk procedure in this EPP patient. The management of post-IST after these combined transplantations remains a challenge and needs to be further established.

Erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disorder of the haem metabolic pathway characterised by accumulation of protoporphyrin in blood, erythrocytes and tissues, and cutaneous manifestations of photosensitivity. EPP has been reported worldwide, with prevalence between 1:75,000 and 1:200,000. It usually manifests in early infancy upon the first sun exposures. EPP is characterised by cutaneous manifestations of acute painful photosensitivity with erythema and oedema, sometimes with petechiae, together with stinging and burning sensations upon exposure to sunlight, without blisters. These episodes have a variable severity depending on the exposure duration and may result in chronic permanent lesions on exposed skin. As protoporphyrin is a lipophilic molecule that is excreted by the liver, EPP patients are at risk of cholelithiasis with obstructive episodes, and chronic liver disease that might evolve to rapid acute liver failure. In most patients, EPP results from a partial deficiency of the last enzyme of the haem biosynthetic pathway, ferrochelatase, EC 4.99.1.1/FECH (encoded by the FECH gene). EPP appears to be inherited as an autosomal dominant disease, the clinical expression of which is modulated by the presence of the hypomorphic FECH IVS3-48C allele trans, but recessive inheritance with two mutated FECH alleles has also been described. In about 2% of patients, overt disease was recently shown to be caused by gain-of-function mutations in the erythroid-specific aminolevulinic acid synthase 2 (ALAS2/ALAS, EC 2.3.1.27) gene and named X-linked dominant protoporphyria. Diagnosis is established by finding increased levels of protoporphyrin in plasma and red blood cells, and detection of a plasma fluorescence peak at 634 nm. Investigations for hepatic involvement, ferrochelatase activity level, genetic analysis (FECH mutations, presence of the hypomorphic FECH IVS3-48C allele trans and ALAS2 mutations) and family studies are advisable. Differential diagnosis includes phototoxic drug reactions, hydroa vacciniforme, solar urticaria, contact dermatitis, angio-oedema and, in some cases, other types of porphyria. Management includes avoidance of exposure to light, reduction of protoporphyrin levels and prevention of progression of possible liver disease to liver failure. As the major risk in EPP patients is liver disease, a regular follow-up of hepatic involvement is essential. Sequential hepatic and bone marrow transplantation should be considered as a suitable treatment for most severe cases of EPP with hepatic involvement. EPP is a lifelong disorder whose prognosis depends on the evolution of the hepatic disease. However, photosensitivity may have a significant impact on quality of life of EPP patients.

Telbivudine for the treatment of hepatitis B disease

Chronic hepatitis B affects approximately 350 million individuals worldwide leading to approximately 500,000 deaths annually. Current therapy includes immune modulators such as IFN-α and the oral antiviral agents, nucleoside analogs such as lamivudine and entecavir, and nucleotide analogs such as adefovir and tenofovir. Recently, telbivudine was approved in the USA for treatment of HBV disease. It is a synthetic nucleoside analog of thymidine that requires phosphorylation to convert to the active triphosphate form. Telbivudine is rapidly absorbed with a long half-life allowing for once-daily dosing. Clinical trials have demonstrated superior antiviral efficacy compared with lamivudine. Telbivudine has shown good correlations between antiviral efficacy at 24 weeks and a favorable outcome at 2 years. Telbivudine is well-tolerated, although monitoring for myopathies is recommended. Telbivudine resistance rates were lower compared with lamivudine. Telbivudine is an option for monotherapy in naive patients or for use in combination therapy in the treatment of chronic hepatitis B.

Protection from phototoxic injury during surgery and endoscopy in erythropoietic protoporphyria

Erythropoietic protoporphyria is an inherited condition characterized by pronounced solar photosensitivity and in a minority of patients severe liver disease that necessitates liver transplantation for survival. Phototoxic injury to abdominal organs and skin has been reported in several cases of liver transplantation surgery, including a few transplants in which protective light filters were used. This study discusses the optimal characteristics of light filters used during liver transplantation surgery. An experimental model is used to evaluate the relative protection of different filters, and the results are compared with theoretical calculations regarding the risk for phototoxic injury from light sources in health-care procedures. Whether protective measures are warranted in other illuminated procedures besides liver transplantation has been discussed often but never studied. This study elucidates the risk for phototoxic injury in endoscopy, laparoscopy, and non-liver transplant surgery. A theoretical model and epidemiological data are considered. Our findings indicate that endoscopy, laparoscopy, and surgical procedures other than liver transplantation are safe in the noncholestatic protoporphyria patient and that general recommendations for using filters in these situations are not warranted. Among the tested filters, a flexible yellow filter omitting wavelengths below 470 nm is recommended for liver transplant surgery. This filter has been readily accepted by surgeons and offers a good balance between protection and altered visual color perception. The experimental model, using hemolysis of protoporphyrin-loaded erythrocytes as a measure of phototoxicity, has substantiated theoretical findings on relative filter protection.