title: Manganese oxidation state as a cause of irritant patch test reactions.
abstract: BACKGROUND
  Manganese chloride (MnCl2) 2.5% is included in the extended metals patch test series to evaluate patients for contact hypersensitivity to this metal salt.
  
  
  OBJECTIVE
  The objective of this study was to prospectively determine the rate of allergic and irritant patch test reactions to MnCl2 (Mn(II)), Mn2O3 (Mn(III)), and KMnO4 (Mn(VII)) in a cohort of patients undergoing patch testing.
  
  
  METHODS
  Fifty-eight patients were patch tested with MnCl2, Mn2O3, and KMnO4, each at 2.5% in petrolatum. Patch readings were taken at 48, and 72 or 96 hours, and scored using standard methods. Cultured monolayers of keratinocytes (KCs) were exposed to MnCl2, Mn2O3, and KMnO4 in aqueous culture medium, and cell survival and cytokine release were studied.
  
  
  CONCLUSIONS
  MnCl2 caused irritant patch test reactions in 41% of the cohort, whereas Mn2O3 and KMnO4 caused a significantly lower rate of irritant reactions (both 3%). No allergic morphologies were observed. Similarly, in cultured KC monolayers, only MnCl2 was cytotoxic to KC and induced tumor necrosis factor α release.The oxidation state of manganese used for patch testing affects the irritancy of this metal salt, as Mn(II) caused an unacceptably high rate of irritant reactions in a cohort of patients. In vitro studies confirmed these clinical data, as only Mn(II) was cytotoxic to cultured monolayers of KC.
authors.affiliation: From the Departments of *Dermatology and †Microbiology/Immunology, University of Maryland School of Medicine, Baltimore MD; ‡Department of Dermatology, La Sapienza University, Rome, Italy; and §Department of Medicine, University of Maryland School of Medicine, Baltimore MD.
authors.forename: Laurie
authors.initials: L
authors.lastname: Shallcross
authors.forename: Simon
authors.initials: S
authors.lastname: Ritchie
authors.forename: Erin
authors.initials: E
authors.lastname: Harberts
authors.forename: Antonella
authors.initials: A
authors.lastname: Tammaro
authors.forename: Joanna
authors.initials: J
authors.lastname: Gaitens
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Gaspari
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002712:Chlorides / Q000009:adverse effects* / Q000737:chemistry; D017449:Dermatitis, Allergic Contact / Q000209:etiology; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000502:physiology*; D008297:Male; D017895:Manganese Compounds / Q000009:adverse effects* / Q000737:chemistry; D008875:Middle Aged; D010084:Oxidation-Reduction; D010087:Oxides / Q000009:adverse effects* / Q000737:chemistry; D010328:Patch Tests; D011196:Potassium Permanganate / Q000009:adverse effects* / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D010087:Oxides; D014409:Tumor Necrosis Factor-alpha; D011196:Potassium Permanganate; C027424:manganese oxide; C025340:manganese chloride