Porphyria cutanea tarda in Scotland: underlying associations and treatment approaches

BACKGROUND

Despite its rarity, porphyria cutanea tarda (PCT) is globally recognized as the most common form of cutaneous porphyria. This study aims to review the underlying associations and treatment of PCT in Scotland.

METHODS

We retrospectively reviewed data on 27 patients diagnosed with PCT between 1987 and 2022 at the Scottish Cutaneous Porphyria Service.

RESULTS

Males slightly predominated (66.7%). The mean ± standard deviation (SD) age at diagnosis was 55.6 ± 12.5 years. Common associated factors were heavy alcohol intake (88.5%), genetic hemochromatosis (72%), smoking (45.5%), and hepatitis C virus infection (16%). Most had multiple associated factors (70.4%). Patients with genetic hemochromatosis with the C282Y genotype exhibited higher median transferrin saturation (69.5 vs. 35, P = 0.004) and ferritin levels (observed in males only) (1175 vs. 339; P = 0.014) than those with the H636D genotype. Most (52%) received combination therapy of venesection and antimalarials, followed by venesection monotherapy (32%) and antimalarial monotherapy (16%). Overall, 95.2% achieved biochemical improvement. Median time to improvement was 7, 5, and 9 months with venesection, antimalarial, and combined treatments, respectively (P = 0.173). Biochemical remission was achieved in 50% of patients. Remission occurred in 2/4 of patients with antimalarial monotherapy (median time 19 months) and 9/13 patients with combined treatment (median time 26 months). Biochemical relapse was found in three patients, all of whom received combination therapy.

CONCLUSION

Excess alcohol intake and genetic hemochromatosis were the most common underlying associations with PCT in our Scottish cohort. Treatment for PCT should be individualized, and long-term follow-up is needed to monitor for disease relapse.

Update on the Porphyrias

The porphyrias are a group of rare diseases, each resulting from a defect in a different enzymatic step of the heme biosynthetic pathway. They can be broadly divided into two categories, hepatic and erythropoietic porphyrias, depending on the primary site of accumulation of heme intermediates. These disorders are multisystemic with variable symptoms that can be encountered by physicians in any specialty. Here, we review the porphyrias and describe their clinical presentation, diagnosis, and management. We discuss novel therapies that are approved or in development. Early diagnosis is key for the appropriate management and prevention of long-term complications in these rare disorders.

Dermatological Manifestations in Patients With Chronic Kidney Disease: A Review

Chronic kidney disease (CKD) is a progressive disease and has multiple clinical manifestations; when CKD reaches the end stage, at least one cutaneous manifestation appears due to some increased toxin levels or a constant proinflammatory state. Nonspecific manifestations include pruritus, xerosis, pigmentation disorders, acquired ichthyosis, purpuric spots, and nail disorders. Some specific manifestations are bullous dermatoses, acquired perforating dermatoses (APD), eruptive xanthoma, access site infections, calcifying disorders, and nephrogenic systemic fibrosis (NSF). All these cutaneous changes negatively impact patients; early recognition and diagnosis of these dermatoses will make a difference in their quality of treatment. Exploring a patient's skin is fundamental to suspect some diseases and increased toxin levels; pruritus occurs when uremic toxins are raised, and nail disorders are associated with hypoalbuminemia. This review provides the clinician with information on the clinical manifestations that occur in CKD, including epidemiology, pathophysiology, clinical manifestations, diagnosis, histopathology, treatment, and life impact of the dermatoses in CKD.

A Rare Case of Hereditary Hemochromatosis Presenting With Porphyria Cutanea Tarda

Hereditary hemochromatosis is an autosomal recessive condition with incomplete penetrance that is most commonly caused by a mutation in the HFE gene. Hereditary hemochromatosis can remain asymptomatic in some patients until triggered by certain events. Porphyria cutanea tarda is a condition that can lead to iron overload due to defective synthesis of heme and can cause the onset of adult-onset hereditary hemochromatosis. Herein, we present a case where a 77-year-old man presented with painful blisters on the sun-exposed areas of his hands and was diagnosed with porphyria cutanea tarda. Further testing for mutations in the HFE gene given elevated ferritin was performed and returned positive, which confirmed the diagnosis of adult-onset hereditary hemochromatosis. The patient received serial therapeutic phlebotomy for iron overload and adopted lifestyle modifications such as avoiding sun exposure of upper extremities. The patient's blisters and laboratory iron panel parameters improved with continued phlebotomy. Therapeutic phlebotomy has been demonstrated to be an effective first-line therapy in patients with dual diagnosis. Our case highlights that cutaneous symptoms due to porphyria cutanea tarda may be the first presenting symptom in patients with underlying hemochromatosis.

Multiple focal fatty changes in the liver in patients with porphyria cutanea tarda: A case series and review of the literature

Porphyria cutanea tarda (PCT) is commonly diagnosed in cases where multiple hyperechoic nodules are observed in the liver. Pathologically, these nodules associated with PCT are focal fatty deposits. We report here, seven cases of PCT with fatty changes over multiple foci in the liver. Furthermore, the characteristics of ultrasonography (US) findings of 32 previously reported cases are summarized. The US features of these nodules showed a homogenous hyperechoic or hyperechoic rim pattern, partial confluence, and no mass effect in the vascular structures. Because multiple hyperechoic liver nodules occasionally mimic malignancies, and because their diagnosis can be challenging, clinicians should consider checking urine porphyrin levels to rule out PCT when such nodules are observed on US.

Risk of Hepatocellular Carcinoma in Patients with Porphyria: A Systematic Review

Simple Summary

Porphyria is a metabolic condition which leads to reduced heme production. While it involves multiple organs systems, porphyria affecting the liver can lead to elevations in hepatic enzymes, progressive fibrosis, cirrhosis and eventually malignancy. Our study looked at the prevalence of liver cancer in patients with porphyria. Overall, we found that patients with porphyria are at increased risk of developing hepatic malignancy. As a result, patients with porphyria should undergo routine surveillance for detecting primary liver malignancy.

Abstract

Acute porphyrias are a group of metabolic disorders resulting in defective porphyrin synthesis and reduced heme production, which carries a risk of malignancy. Porphyrias are inborn defects in the heme biosynthesis pathway resulting in neurovisceral manifestations and cutaneous photosensitivity attacks with multi-systemic involvement. Its estimated prevalence nears 5 per 100,000 patients worldwide. Subclinical liver disease is common, which can progress into transaminitis, fibrosis, cirrhosis, and malignancy. However, data on the incidence of primary liver cancer are lacking. We aim to determine the risk of hepatocellular carcinoma (HCC) in patients with porphyria. A systematic review and pooled analysis were conducted through 2021 on studies assessing blood tests, imaging, cancer development, liver transplant, surgical resection, and outcomes in porphyria. In total, 19 studies, which included 7381 patients with porphyria (3476 females), were considered for the final review. In eight studies, alpha-fetoprotein levels were elevated between 200 and 1000 IU/mL. Of the total cohort of patients with porphyria, primary liver cancer was diagnosed in 351 patients (4.8%), of whom 243 (3.3% of the total) were found to have HCC. A subset of patients was found to have cholangiocarcinoma (n = 18; 0.3% of the total). Interestingly, advanced liver disease or cirrhosis was not a prerequisite for the formation of HCC in a small group of patients. Of the total cohort, 30 patients underwent liver resection, 48 patients underwent liver transplantation, and 327 patients died. Patients with porphyria are at risk of developing primary liver malignancy. Further studies should aim to develop diagnostic and prognostic models aimed at the early detection of HCC in porphyria.

Between a Rock and a Hard Place: Management of Systemic Lupus Erythematosus and Porphyria Cutanea Tarda

Porphyria cutanea tarda (PCT), the most common porphyria, is a rare photodermatosis characterized by fragile, hemorrhagic bullae and erosions with associated milia, hyperpigmentation, and hypertrichosis. SLE is a systemic connective tissue disease with approximately 80% of those affected manifesting cutaneous findings. These include malar and discoid rashes, photosensitivity, bullae, oral ulcerations, as well as a variety of other non-specific findings. In this case we illustrate a rare but established association between these two pathologic entities, and the resulting therapeutic challenge in treating a patient with both conditions. The concurrence of these two diseases poses therapeutic challenges with a paucity of evidence-based recommendations. Management with low dose weekly antimalarial therapy may be the appropriate middle ground in effectively treating the two co-morbid conditions especially in a patient with other underlying systemic conditions.

Forearm porphyrin levels evaluated by digital imaging system are increased in patients with systemic sclerosis compared with patients in pre-clinical stage

We hypothesized that changes in skin characteristics on the forearm could be useful for early diagnosis of systemic sclerosis (SSc). We used VISIA digital imaging system to investigate this possibility for the first time. Twenty-eight Japanese patients who were diagnosed with typical or very early diagnosis of SSc (VEDOSS) were enrolled in this study, and ten age- and gender-matched patients with other disorders were included as a control group. Eight skin characteristics were analyzed. Our method of evaluating forearm skin characteristics was shown to be reproducible. The scores of WRINKLES, TEXTURE, PORES, and PORPHYRINS were higher in SSc subjects with sclerotic forearm skin (SSc forearm+; 11.004, 5.116, 3.230, and 0.084, respectively) and those without (SSc forearm-: 11.915, 4.898, 2.624, 0.0616, respectively) than in the non-SSc control subjects (10.075, 4.496, 2.459, 0.0223, respectively). Also, the scores of SPOTS, TEXTURE, PORES, UV SPOTS, BROWN SPOTS, and PORPHYRINS were elevated in SSc forearm+ (3.182, 5.116, 3.230, 5.761, 6.704, 0.084, respectively) and SSc forearm- patients (2.391, 4.898, 2.624, 9.835, 5.798, 0.0616, respectively) compared with those with VEDOSS (2.362, 4.738, 2.234, 5.999, 4.898, 0.0169, respectively). We found statistical significance in the difference in score of PORPHYRINS between SSc forearm- and VEDOSS groups (p = 0.044), and between SSc forearm+ and VEDOSS groups (p = 0.012). Therefore, they can be used to differentiate VEDOSS from early or mild SSc cases, which is sometimes clinically problematic. Our study also suggests that the porphyrin research will lead to a better understanding of SSc pathogenesis.

Iatrogenic Iron Overload Causing Porphyria Cutanea Tarda in a Patient With a Rare Nonsense Heterozygous UROD Gene Mutation

Porphyria cutanea tarda (PCT) is a rare dermatologic condition characterized by blistering of sun-exposed surfaces and elevated hepatic enzymes. It may infrequently occur as the primary presentation of underlying hemochromatosis. A 61-year-old female with anemia caused by chronic kidney disease and end-stage renal disease on hemodialysis presented with a bullous rash on her hands with associated pruritus. The rash worsened despite conservative treatment. An initial biopsy demonstrated a pauci-inflammatory cell-poor subepidermal cleft. Subsequent workup revealed elevated serum and urine porphyrins, confirming a diagnosis of PCT. Additionally, her skin was darkened and ferritin was elevated. MRI of the liver demonstrated iron overload with genetic testing negative for C282Y or H63D mutations, supporting a diagnosis of secondary hemochromatosis. Further genetic testing revealed that the patient had a rare heterozygous nonsense mutation of the uroporphyrinogen decarboxylase (UROD) gene, for a sequence variant designated c.616C>T, which is predicted to result in premature protein termination (p.Gln206*). PCT occurs due to decreased function of UROD, leading to accumulation of porphyrins causing dermatologic manifestations and liver injury. UROD is inactivated in an iron-dependent process, explaining the mechanistic link between hemochromatosis and PCT.

Role of ABCB1 and glutathione S-transferase gene variants in the association of porphyria cutanea tarda and human immunodeficiency virus infection

In Argentina, porphyria cutanea tarda (PCT) is strongly associated with infection with human immunodeficiency virus (HIV); however, whether the onset of this disease is associated with HIV infection and/or the antiretroviral therapy has not been determined. The ABCB1 gene variants c.1236C>T, c.2677G>T/A and c.3435C>T affect drug efflux. The GSTT1 null, GSTM1 null and GSTP1 (c.313A>G) gene variants alter Glutathione S-transferase (GST) activity, modifying the levels of xenobiotics. The aim of the present study was to evaluate the role of genetic variants in initiation of PCT and to analyze the genetic basis of the PCT-HIV association. Control individuals, and HIV, PCT and PCT-HIV patients were recruited, PCR-restriction fragment length polymorphism was used to genotype the ABCB1 and GSTP1 variants, and multiplex PCR was used to study the GSTM1 and GSTT1 variants. The high frequency of c.3435C>T (PCT and PCT-HIV) and c.1236C>T (PCT) suggested that the onset of PCT were not specifically related to HIV infection or antiretroviral therapy for these variants. c.2677G>T/A frequencies in the PCT-HIV patients were higher compared with the other groups, suggesting that a mechanism involving antiretroviral therapy served a role in this association. PCT-HIV patients also had a high frequency of GSTT1 null and low frequency for GSTM1 null variants; thus, the genetic basis for PCT onset may involve a combination between the absence of GSTT1 and the presence of GSTM1. In conclusion, genes encoding for proteins involved in the flow and metabolism of xenobiotics may influence the PCT-HIV association. The present study is the first to investigate the possible role of GST and ABCB1 gene variants in the triggering of PCT in HIV-infected individuals, to the best of our knowledge, and may provide novel insights into the molecular basis of the association between PCT and HIV.

Porphyria cutanea tarda associated with elevated serum ferritin, iron overload, and a bone morphogenetic protein 6 genetic variant

A man aged 51 years was referred to dermatology for hand dermatitis. The dorsal hands and fingers had superficial erosions with pale pink shallow scars and milia suggestive of porphyria cutanea tarda (PCT). Urine and fecal studies were typical of PCT. The patient had daily alcohol use and was found to have elevated serum ferritin, aspartate aminotransferase, and alanine transaminase. Genetic testing for common hemochromatosis genetic variants (HFE C282Y and H63D) was normal. He underwent next-generation sequencing analysis using the 16-gene hyperferritinemia gene panel for genes known to be associated with hereditary hyperferritinemia, iron overload, or both and was discovered to have a genetic variant in bone morphogenetic 6 (BMP6, c.287T> C, p.Leu96Pro). The skin lesions improved with phlebotomy therapy.

Sclerodermiform manifestations of porphyria cutanea tarda secondary to hepatitis C

A 63-year-old black female patient with blisters and exulcerations on the face, neck, upper limbs, and subsequent evolution with hypochromic sclerotic areas and alopecia, is reported. Chronic hepatitis C and presence of high levels of porphyrins in urine were demonstrated. There was complete remission with the use of hydroxychloroquine, photoprotection, and treatment of hepatitis. Significant sclerodermoid involvement of the skin as a manifestation of porphyria cutanea tarda secondary to hepatitis C emphasizes the importance of diagnostic suspicion regarding skin manifestation in order to indicate the appropriate therapy, and to minimize the hepatic morbidity.

Porphyria Cutanea Tarda Associated With Acute Hemorrhagic Pancreatitis

Porphyria cutanea tarda (PCT) is a condition of dysregulated heme synthesis that leads to accumulation of photosensitizing precursors with resultant fragility and blistering of the skin. It can be hereditary or acquired and has been known to be associated with hepatic C virus, alcohol, HIV, and estrogen. In this article, we report an unusual presentation of PCT associated with acute hemorrhagic pancreatitis in a 57-year-old man. He presented initially to a community hospital with acute onset of epigastric abdominal pain and new-onset ascites. Lipase was elevated. Diagnostic paracentesis was grossly bloody. He was then transferred to our institution for concern for acute hemorrhagic pancreatitis. On arrival, physical examination demonstrated vesicles and bullae with erythematous bases, in different stages of healing seen over the dorsal aspects of both hands with scaling, scarring, and hypopigmentation and hyperpigmentation of the skin. Laboratory evaluation and skin biopsy confirmed the diagnosis of PCT. Search for an underlying etiology failed to reveal typical predisposing factors. This report illustrates that acute hemorrhagic pancreatitis may be an underlying etiology for PCT.

Role of Vitamin C in Skin Diseases

Vitamin C (ascorbic acid) plays an important role in maintaining skin health and can promote the differentiation of keratinocytes and decrease melanin synthesis, leading to antioxidant protection against UV-induced photodamage. Normal skin needs high concentrations of vitamin C, which plays many roles in the skin, including the formation of the skin barrier and collagen in the dermis, the ability to counteract skin oxidation, and the modulation of cell signal pathways of cell growth and differentiation. However, vitamin C deficiency can cause or aggravate the occurrence and development of some skin diseases, such as atopic dermatitis (AD) and porphyria cutanea tarda (PCT). Levels of vitamin C in plasma are decreased in AD, and vitamin C deficiency may be one of the factors that contributes to the pathogenesis of PCT. On the other hand, high doses of vitamin C have significantly reduced cancer cell viability, as well as invasiveness, and induced apoptosis in human malignant melanoma. In this review, we will summarize the effects of vitamin C on four skin diseases (porphyria cutanea tarda, atopic dermatitis, malignant melanoma, and herpes zoster and postherpetic neuralgia) and highlight the potential of vitamin C as a therapeutic strategy to treat these diseases, emphasizing the clinical application of vitamin C as an adjuvant for drugs or physical therapy in other skin diseases.

The devil's in the dosing: severe drug-induced liver injury in a hydroxychloroquine-naive patient with subacute cutaneous lupus erythematosus and porphyria cutanea tarda

A 29-year-old woman with a 1.5 year history of photosensitive skin lesions on her hands presented with a malar rash, bullous lesions on her hands, and was diagnosed with subacute lupus erythematosus after serologies revealed a positive antinuclear antibody test (1:2560), and antibodies to Ro/SSA and dsDNA. Hydroxychloroquine (400 mg/day) was prescribed and the patient developed severe drug-induced liver injury. Biopsy of her bullous skin lesions was consistent with porphyria cutanea tarda, as were her serological and urinary exams. She was successfully treated with therapeutic phlebotomy. This case identifies porphyria cutanea tarda as an important differential diagnosis for the rheumatologist to consider when evaluating patients with bullous skin lesions. Hydroxychloroquine in lower doses is an effective treatment for porphyria cutanea tarda; at doses used to treat systemic lupus erythematosus and subacute cutaneous lupus, there is a potentially life-threatening complication of hepatotoxicity.

Porphyria and kidney diseases

The kidneys, after the bone marrow and liver, are third in terms of the amounts of haem synthesized daily. Haem is incorporated into haemoproteins that are critical to renal physiology. In turn, disturbances in haem metabolism interfere with renal physiology and are tightly interrelated with kidney diseases. Acute intermittent porphyria causes kidney injury, whereas medical situations associated with end-stage renal disease, such as porphyrin accumulation, iron overload and hepatitis C, participate in the inhibition of uroporphyrinogen decarboxylase and predispose the individual to porphyria cutanea tarda. Even if some of these interactions have been known for a long time, the clinical situations associated with these interrelations have strikingly evolved over time with the advent of new therapeutic strategies for dialysis therapy and a better understanding of the pathophysiological mechanisms of porphyria-associated kidney disease. Physicians should be aware of these interactions. The aim of this review is to summarize the complex interactions between kidney physiology and pathology in the settings of porphyria and to emphasize their often-underestimated importance.

Genetic ancestry of patients with porphyria cutanea tarda in a country with mixed races: a cross-sectional study (Rio de Janeiro - Brazil)

Porphyria cutanea tarda has a complex etiology with genetic factors not completely elucidated. The miscegenation of the Brazilian population has important implications in the predisposition to diseases. There are no studies concerning the genetic ancestry of patients with porphyria cutanea tarda from a mixed population. Thirty patients living in Rio de Janeiro with sporadic porphyria cutanea tarda were studied for the genetic ancestry through informative markers - INDELS. There was a significant predominance of European ancestry across the sample of patients with porphyria cutanea tarda (70.2%), and a small contribution of African and Amerindian ancestry, 20.1% and 10.9%, respectively.

Clinical applications of therapeutic phlebotomy

Phlebotomy is the removal of blood from the body, and therapeutic phlebotomy is the preferred treatment for blood disorders in which the removal of red blood cells or serum iron is the most efficient method for managing the symptoms and complications. Therapeutic phlebotomy is currently indicated for the treatment of hemochromatosis, polycythemia vera, porphyria cutanea tarda, sickle cell disease, and nonalcoholic fatty liver disease with hyperferritinemia. This review discusses therapeutic phlebotomy and the related disorders and also offers guidelines for establishing a therapeutic phlebotomy program.

Reflectance confocal microscopy in the diagnosis of vesicobullous disorders: case series with pathologic and cytologic correlation and literature review

BACKGROUND

Vesicobullous disorders are characterized by intraepidermal or subepidermal blistering resulting from different pathogenetic mechanisms. The diagnosis is generally based on clinical examination and semi-invasive/invasive procedures such as cytology and histopathology. In vivo reflectance confocal microscopy (RCM) is a non-invasive technique for real-time, en face imaging of the epidermis and upper dermis with high resolution close to conventional histopathology.

PURPOSE

To evaluate RCM features of different vesicobullous diseases and correlate with cytologic and histopathologic examination.

METHODS

Ten patients (6M/4F, age range: 9-81 years) affected by blistering diseases, such as herpes simplex, herpes zoster, Kaposi's varicelliform eruption, pemphigus vulgaris, Hailey-Hailey disease, bullous pemphigoid, and porphyria cutanea tarda were evaluated using a handheld RCM device.

RESULTS

In our study, a clear correlation between RCM and Tzanck's test and/or histopathology was observed. RCM allowed in all cases an easy identification of the blister spaces and of the split levels, and in some cases specific features were detected, such as giant keratinocytes in herpes infections and acantholytic cells in pemphigus vulgaris and Hailey-Hailey disease.

CONCLUSION

Reflectance confocal microscopy may support the clinical diagnosis of vesicobullous disorders and indicate to the physician the appropriate patient management and/or the need for further investigation.

Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria

Porphyrias are diverse disorders that arise from various inherited enzyme defects in the heme biosynthesis pathway, except for porphyria cutanea tarda (PCT), in which the enzyme deficiency in most cases is acquired. The biosynthetic blocks resulting from the defective enzymes are largely expressed either in the liver or bone marrow, the sites where the majority of heme is produced. Although the pathophysiologic mechanisms of the clinical manifestations of the porphyrias are not fully understood, two cardinal features prevail: skin photosensitivity and neurologic symptoms of intermittent autonomic neuropathy, acute neurovisceral attacks, and disorders of the nervous system. The primary diagnosis of the proband is based on biochemical testing, which is not always able to identify acute porphyrias, especially in asymptomatic family carriers when heme precursors and porphyrins excretion is normal, low-normal and high-reduced values of enzyme activity overlap, and hematological diseases responsible for abnormal blood cells distribution coexist. Molecular analysis of gene mutations responsible for each type of porphyria is the best diagnostic approach for symptomatic as well as presymptomatic gene carriers.

Human immunodeficiency virus and risk of porphyria cutanea tarda: a possible association examined in a large hospital

BACKGROUND

Human immunodeficiency virus (HIV) infection has been reported to be a risk factor for porphyria cutanea tarda (PCT).

PURPOSE

To assess the strength of the association between HIV infection and PCT in a large hospital setting.

METHODS

All patients (N = 210) diagnosed of PCT between 1990 and 2014 were retrospectively investigated for HIV infection and co-precipitating factors. High-performance liquid chromatography was used to assess the appearance of pre-PCT urinary porphyrin abnormalities among a group (N = 22) of HIV-infected patients without PCT using the urine of patients co-infected with hepatitis C virus (HCV) without PCT for comparison.

RESULTS

Twenty-six HIV-infected patients (19 males and seven females) were diagnosed of PCT. During the same interval of time, ~8000 different patients infected with HIV were attended in the hospital of infectious diseases department. Examination of risk factors showed that 25 out of 26 of the PCT patients with HIV were co-infected with HCV. No chromatographic abnormalities were found in the urine of non-PCT-HIV-infected patients, whereas 39% co-infected patients showed urinary porphyrin abnormalities.

CONCLUSIONS

In our large hospital series, the appearance of PCT among HIV-infected patients is low (<1%) and most present co-infection with HCV. Therefore, in most HIV-infected patients with PCT, hepatitis C and not HIV may induce uroporphyrinogen decarboxylase deficiency.

Porphyria cutanea tarda in a human immunodeficiency virus-infected patient: A rare scenario in India

A 30-year-old unmarried, heterosexual male presented with an 8-month history of tense blistering skin lesions over the hands. Physical examination revealed facial hypertrichosis and multiple erosions with crusts and scars over the dorsum of both hands. Woods lamp examination of the urine, histopathology and urinary porphyrin levels were suggestive of porphyria cutanea tarda (PCT). The patient responded well to hydroxychloroquine and antiretroviral drugs. This case report calls for a detailed evaluation and HIV testing in every patient with PCT.

Desferrioxamine treatment of porphyria cutanea tarda in a patient with HIV and chronic renal failure

Porphyria cutanea tarda (PCT) can occur in HIV patients. Current evidence suggests that HIV infection may interfere with the hepatic cytochrome oxidase system, leading to porphyrin metabolism impairment. Moreover, chronic hemodialysis in renal failure may be a risk factor for PCT. In addition to the contributory factors for PCT associated to HIV infection, it is possible that porphyrin accumulation secondary to renal failure may play a role in the expression of this disease. We report a case of PCT in an HIV-1 infected patient under blood dialysis, refractory to antimalarials and controlled with desferrioxamine.

Hepatitis C, porphyria cutanea tarda and liver iron: an update

Porphyria cutanea tarda (PCT) is the most common form of porphyria across the world. Unlike other forms of porphyria, which are inborn errors of metabolism, PCT is usually an acquired liver disease caused by exogenous factors, chief among which are excess alcohol intake, iron overload, chronic hepatitis C, oestrogen therapy and cigarette smoking. The pathogenesis of PCT is complex and varied, but hereditary or acquired factors that lead to hepatic iron loading and increased oxidative stress are of central importance. Iron loading is usually only mild or moderate in degree [less than that associated with full-blown haemochromatosis (HFE)] and is usually acquired and/or mutations in HFE. Among acquired factors are excessive alcohol intake and chronic hepatitis C infection, which, like mutations in HFE, decrease hepcidin production by hepatocytes. The decrease in hepcidin leads to increased iron absorption from the gut. In the liver, iron loading and increased oxidative stress leads to the formation of non-porphyrin inhibitor(s) of uroporphyrinogen decarboxylase and to oxidation of porphyrinogens to porphyrins. The treatment of choice of active PCT is iron reduction by phlebotomy and maintenance of a mildly iron-reduced state without anaemia. Low-dose antimalarials (cinchona alkaloids) are also useful as additional therapy or as alternative therapy for active PCT in those without haemochromatosis or chronic hepatitis C. In this review, we provide an update of PCT with special emphasis upon the important role often played by the hepatitis C virus.

Uroporphyria in the Cyp1a2-/- mouse

Cytochrome P4501A2 (Cyp1a2) is important in the development of uroporphyria in mice, a model of porphyria cutanea tarda in humans. Heretofore, mice homozygous for the Cyp1a2-/- mutation do not develop uroporphyria with treatment regimens that result in uroporphyria in wild-type mice. Here we report uroporphyria development in Cyp1a2-/- mice additionally null for both alleles of the hemochromatosis (Hfe) gene and heterozygous for deletion of the uroporphyrinogen decarboxylase (Urod) gene (genotype: Cyp1a2-/-;Hfe-/-;Urod+/-), demonstrating that upon adding porphyria-predisposing genetic manipulations, Cyp1a2 is not essential. Cyp1a2-/-;Hfe-/-;Urod+/- mice were treated with various combinations of an iron-enriched diet, parenteral iron-dextran, drinking water containing δ-aminolevulinic acid and intraperitoneal Aroclor 1254 (a polychlorinated biphenyl mixture) and analyzed for uroporphyrin accumulation. Animals fed an iron-enriched diet alone did not develop uroporphyria but uroporphyria developed with all treatments that included iron supplementation and δ-aminolevulinic acid, even with a regimen without Aroclor 1254. Hepatic porphyrin levels correlated with low UROD activity and high levels of an inhibitor of UROD but marked variability in the magnitude of the porphyric response was present in all treatment groups. Gene expression profiling revealed no major differences between genetically identical triple cross mice exhibiting high and low magnitude porphyric responses from iron-enriched diet and iron-dextran supplementation, and δ-aminolevulinic acid. Even though the variation in porphyric response did not parallel the hepatic iron concentration, the results are compatible with the presence of a Cyp1a2-independent, iron-dependent pathway for the generation of uroporphomethene, the UROD inhibitor required for the expression of uroporphyria in mice and PCT in humans.

Structural and kinetic characterization of mutant human uroporphyrinogen decarboxylases

Porphyria cutanea tarda (PCT) is caused by inhibition of uroporphyrinogen decarboxylase (URO-D) activity in hepatocytes. Subnormal URO-D activity results in accumulation and urinary excretion of uroporphyrin and heptacarboxyl porphyrin. Heterozygosity for mutations in the URO-D gene is found in the familial form of PCT (F-PCT). Over 70 mutations of URO-D have been described but very few have been characterized structurally. Here we characterize 3 mutations in the URO-D gene found in patients with F-PCT, G318R, K297N, and D306Y. Expression of the D306Y mutation results in an insoluble recombinant protein. G318R and K297N have little effect on the structure or activity of recombinant URO-D, but the proteins display reduced stability in vitro.

Autoantibodies to human cytosol: a marker of sporadic porphyria cutanea tarda

The enzymes potentially involved in the pathogenesis of sporadic porphyria cutanea tarda (PCT) reside in liver cytosoles and microsomes. PCT is frequently associated with hepatitis C virus (HCV) infection, which is in turn associated with autoimmune manifestations. To investigate whether autoimmune reactions, possibly triggered by HCV, are involved in the pathogenesis of PCT, we measured by immunoblot autoantibodies to human cytosolic and microsomal liver fractions in 82 patients with PCT (77% with HCV infection), 105 with other liver disorders and 40 healthy subjects. Anti-liver cytosolic antibodies were more frequent in PCT patients (38/82, 46%) than in pathological controls (P < 0.05-P < 0.001) or in healthy subjects (3/40, 8%, P < 0.001). Among PCT patients, anticytosolic antibodies were more frequent in HCV positive (36/63, 57%) than in HCV negative (2/19, 11%, P < 0.05) cases. Reactivity to a 40-kDa cytosolic polypeptide was present in 20 PCT patients (19 HCV positive), being more frequent than in all pathological controls (P < 0.01-P < 0.0001). Histological activity index (P = 0.04) and antibodies to HCV (P = 0.027) - but not HCV RNA - were associated independently with anticytosolic antibodies as assessed by multivariate analysis. In contrast, frequency of antiliver microsomal antibodies was similar in PCT patients (24/82, 29%) and pathological controls (8-26%), being higher in the autoimmune hepatitis control group (23/23, 100%, P < 0.0001). In conclusion, anticytosolic antibodies, particularly to a 40-kDa polypeptide, are frequent in PCT and associated with HCV infection and severity of liver damage.