Mueller, Wilhelm

Stauch, Thomas

Vogeser, Michael

English

Anderson KE

Sato H

Crossref

Inter-laboratory survey of erythrocyte free protoporphyrin quantification – announcement of a pilot study

Open Access LMU ( Ludwig-Maximilians-Univ. München)

Clin Chem Lab Med 2008;46(9):1340–1341  2008 by Walter de Gruyter • Berlin • New York. DOI 10.1515/CCLM.2008.268 2007/234Article in press - uncorrected proofLetter to the EditorInter-laboratory survey of erythrocyte free protoporphyrinquantification – announcement of a pilot studyMichael Vogeser1,*, Wilhelm Mu¨ller2 andThomas Stauch31 Institute of Clinical Chemistry, University ofMunich, Munich, Germany2 Chromsystems, Munich, Germany3 Labor Professor Seelig & Kollegen, Karlsruhe,GermanyKeywords: Erythropoietic protoporphyria (EPP); inter-laboratory survey.Erythropoietic protoporphyria (EPP; E80.0, ICD-10) isan inherited disorder resulting from partially deficientactivity of ferrochelatase, the last enzyme in the hemebiosynthetic pathway (1). In EPP, protoporphyrinaccumulates in erythrocytes, bile, and skin, with pho-toactivation of accumulated protoporphyrin causingendothelial injury. Thus, the main symptom of EPP ispainful cutaneous photosensitivity. Diffuse edema ofthe skin in sun-exposed areas may resemble angio-neurotic edema; in most cases, however, burning anditching initially occur without obvious skin damage.Typically the disease becomes symptomatic beforethe age of 2 years, but diagnosis is typically delayedby 10 years (2), and late-onset cases have been rec-ognized in hematological diseases (3). Severe and insome cases fulminating liver disease occurs in 5% ofEPP patients, potentially requiring liver transplanta-tion (4, 5). The disease has an autosomal pseudo-dominant, and in some cases autosomal recessivepattern of inheritance (6, 7), and a variety of muta-tions have been found to cause EPP (8). The disorderhas only been clearly recognized since 1961 (9). Exactdata on the prevalence of EPP are not available: in theUnited Kingdom 389 EPP cases were documented in2006 (2), but substantially more cases must beassumed.An increased concentration of free protoporphyrinin erythrocytes is the laboratory hallmark of EPP.‘‘Free’’ protoporphyrin (protoporphyrin without anycentral atom) is indeed the only heme pathway inter-mediate that accumulates significantly in this disease.Although a number of conditions such as iron-defi-cient erythropoiesis, lead intoxication, and hemato-*Corresponding author: Michael Vogeser, MD, Institute ofClinical Chemistry, Hospital of the University of Munich,Marchioninistraße 15, 81377 Munich, GermanyPhone: q49-89-70953221, Fax: q49-89-70956220,E-mail: michael.vogeser@med.uni-muenchen.delogical diseases can lead to increased erythrocytezinc protoporphyrin concentrations, significantlyincreased free protoporphyrin concentrations areassumed to be found exclusively in EPP. Slightlyincreased levels of free protoporphyrin are observedunder conditions of zinc depletion and iron deficiency,sometimes in sideroblastic anemia and other hema-tological diseases, and in homozygous or compoundheterozygous porphyrias such as hepatoerythropoie-tic porphyria, Doss porphyria (d-aminolevulinatedehydratase-deficiency porphyria) and congenitalerythropoietic porphyria (Morbus Guenther). How-ever, clinically relevant concentrations are neverattained in these cases.Since EPP does not present with visible or charac-teristic skin abnormalities in many cases (10), eryth-rocyte protoporphyrin measurement is of essentialimportance for primary diagnosis of EPP in childrenand adolescents with avoidance behavior towardssun exposure. In the follow-up of EPP patients, eryth-rocyte protoporphyrin measurement can potentiallyhelp (in addition to quantification of fecal protopor-phyrin excretion and the isomeric ratio of copropor-phyrin in urine) in early recognition of transition ofthe disease to a fulminate phase, in which worseningcholestasis leads to further accumulation of protopor-phyrin in a vicious cycle (4, 5).Quantification of free erythrocyte protoporphyrinconcentrations still represents an analytical challengeand is performed in only a few specialized laborato-ries. The first approach to laboratory diagnosis of EPPwas the demonstration of fluorescent red cells (‘‘fluo-rocytes’’) in blood films viewed under ultraviolet light(11). Several chromatographic methods for specificquantification of erythrocyte free protoporphyrinweresubsequently described (12, 13). In such assays, sam-ple preparation with full-recovery analyte extractionis delicate and the chromatographic separation of freefrom zinc-chelated protoporphyrin is demanding.Blood-based materials for calibration and qualitycontrol of erythrocyte free protoporphyrin quantifica-tion are not commercially available at present and noproficiency testing schemes have been implemented.Indeed, there are no data published on agreementbetween free erythrocyte measurements performedin different laboratories. We therefore decided toorganize an inter-laboratory survey study of freeerythrocyte protoporphyrin measurement. Data fromthis survey will be important in achieving harmon-ization of protoporphyrin measurement in the future.For this survey, 30 mL of heparinized whole bloodwas sampled from an EPP patient after informed con-Bereitgestellt von | provisional accountAngemeldet | 129.187.254.47Heruntergeladen am | 14.11.13 15:47Vogeser et al.: Survey of erythrocyte free protoporphyrin quantification 1341Article in press - uncorrected proofsent and approval by the Institutional Review Board.Erythrocytes were separated from the plasma bycentrifugation, and washed with saline. Aliquots ofthe sample were prepared and lyophilized in light-protected vials in an industrial setting (Chromsys-tems, Munich, Germany).We can now invite interested colleagues to requestan aliquot of this sample (michael.vogeser@med.uni-muenchen.de) for free erythrocyte protoporphyrinmeasurement at no cost. The resulting data will beevaluated after anonymization. It is intended to createa research group with the participants of this surveyand to submit the data from this pilot investigationfor potential publication in Clinical Chemistry andLaboratory Medicine.AcknowledgementsThis study is supported by the Hans-Fischer-Gesellschaft,Munich, GermanyReferences1. Anderson KE, Sassa S, Bishop DF, Desnick RJ. Disordersof heme biosynthesis: X-linked sideroblastic anemia andthe porphyrias. In: Scriver CR, Beaudet AL, Sly WS, ValleD, eds. The metabolic and molecular bases of inheriteddisease, 8th ed. New York: McGraw-Hill, 2001:2991–3062.2. Holme SA, Anstey AV, Finlay AY, Elder GH, BadmintonMN. Erythropoietic protoporphyria in the UK: clinical fea-tures and effect on quality of life. Br J Dermatol2006;155:574–81.3. Bharati A, Badminton MN, Whatley SD, O’Brien DV, BellHK. Late-onset erythropoietic protoporphyria in associ-ation with haematological malignancy. Clin Exp Derma-tol 2006;31:668–70.4. Doss MO, Frank M. Hepatobiliary implications andcomplications in protoporphyria, a 20-year study. ClinBiochem 1989;22:223–9.5. Gross U, Frank M, Doss MO. Hepatic complications oferythropoietic protoporphyria. Photoderm PhotoimmunPhotomed 1998;14:52–7.6. Cox TM. Erythropoietic protoporphyria. J Inher MetabDis 1997;20:258–69.7. Puy H, Deybach JC, Gouya L, Robreau AM, Bourgois M,Lamoril J, et al. The penetrance of dominant erythro-poietic porphyria is modulated by expression of wild-type FECH. Nat Genet 2002;30:27–8.8. Sassa S. Modern diagnosis and management of theporphyrias. Br J Haematol 2006;135:281–92.9. Magnus IA, Jarrett A, Prankerd TA, Rimington C. Eryth-ropoietic protoporphyria. A new porphyria syndromewith solar urticaria due to protoporphyrinaemia. Lancet1961;278:448–51.10. Lecluse AL, Kuck-Koot VC, van Weelden H, SigurdssonV, Russel IM, Frank J, et al. Erythropoietic protoporphy-ria without skin symptoms – you do not always see whatthey feel. Eur J Pediatr 2008;167:703–6.11. Rimmington C, Cripps DJ. Biochemical and fluorescencemicroscopy screening test for erythropoietic protopor-phyria. Lancet 1965;1:624–6.12. Ho J, Guthrie R, Tieckelmann H. Quantitative determi-nation of porphyrins, their precursors and zinc proto-porphyrin in whole blood and dried blood by high-performance liquid chromatography with fluorimetricdetection. J Chromatogr 1987;417:269–76.13. Sato H, Ido K, Kimura K. Simultaneous separation andquantification of free and metal-chelated protoporphy-rins in blood by three-dimensional HPLC. Clin Chem1994;40:1239–44.Bereitgestellt von | provisional accountAngemeldet | 129.187.254.47Heruntergeladen am | 14.11.13 15:47

Biochemical and fluorescence microscopy screening test for erythropoietic protoporphyria. Lancet 1965;1:624–6.

Desnick RJ. Disorders of heme biosynthesis: X-linked sideroblastic anemia and the porphyrias. In:

Erythropoietic protoporphyria in the UK: clinical features and effect on quality of life.

Erythropoietic protoporphyria without skin symptoms – you do not always see what they feel.

Erythropoietic protoporphyria.

Erythropoietic protoporphyria. A new porphyria syndrome with solar urticaria due to protoporphyrinaemia. Lancet 1961;278:448–51.

Hepatic complications of erythropoietic protoporphyria. Photoderm Photoimmun Photomed

Hepatobiliary implications and complications in protoporphyria, a 20-year study. Clin Biochem

Late-onset erythropoietic protoporphyria in association with haematological malignancy. Clin Exp Dermatol

Modern diagnosis and management of the porphyrias.

Quantitative determination of porphyrins, their precursors and zinc protoporphyrin in whole blood and dried blood by highperformance liquid chromatography with fluorimetric detection.

Simultaneous separation and quantification of free and metal-chelated protoporphyrins in blood by three-dimensional HPLC.

The penetrance of dominant erythropoietic porphyria is modulated by expression of wildtype FECH.

Inter-laboratory survey of erythrocyte free protoporphyrin quantification - announcement of a pilot study

https://epub.ub.uni-muenchen.de/17756/1/cclm.2008.268.pdf

Inter-laboratory survey of erythrocyte free protoporphyrin quantification - announcement of a pilot study

Abstract

Similar works

Full text

Available Versions

Crossref

Open Access LMU ( Ludwig-Maximilians-Univ. München)