title: Specificity of granular IgM deposition in folliculosebaceous units and sweat gland apparatus in direct immunofluorescence (DIF) of lupus erythematosus.
abstract: BACKGROUND
  Diagnosis of lupus erythematosus (LE) in direct immunofluorescence testing is based on the finding of positive immunofluorescence at the dermoepidermal junction (DEJ).
  
  
  OBJECTIVE
  We sought to evaluate the sensitivity of IgM deposition at the DEJ and adnexal structures in the diagnosis of lupus erythematosus.
  
  
  METHODS
  We conducted a retrospective study of 100 previously diagnosed cases of lupus erythematosus and 158 cases of other immune-mediated dermatosis. Deposition of IgG, IgM, IgA, and C3 at the DEJ, follicular units, and sweat glands were recorded. Presence or absence of adnexal structures was documented. The immunoreactant deposition was documented as linear, coarse granular, or stippled.
  
  
  RESULTS
  The most frequently deposited immunoreactant in lupus erythematosus cases was IgM along the DEJ and stromal-epithelial junction of hair follicles and sweat glands. IgM deposition along the stromal-epithelial junction of hair follicles and sweat glands was strongly associated with a diagnosis of lupus erythematosus compared with other immune-mediated diseases collectively (P value < .001). The pattern of IgM in lupus and dermatomyositis is granular, in contrast to the linear deposition in the other disorders evaluated.
  
  
  CONCLUSIONS
  This was a retrospective study of archived material.
  
  
  CONCLUSIONS
  Granular IgM deposition at the stromal-epithelial junction of cutaneous adnexal structures suggests a diagnosis of lupus erythematosus or dermatomyositis.
authors.affiliation: Ackerman Academy of Dermatopathology, New York, New York; Department of Dermatology, Kasr Al Ainy Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Amira
authors.initials: A
authors.lastname: Elbendary
authors.affiliation: Ackerman Academy of Dermatopathology, New York, New York; Department of Dermatology, Peking University People's Hospital, Beijing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Ackerman Academy of Dermatopathology, New York, New York.
authors.forename: Manuel
authors.initials: M
authors.lastname: Valdebran
authors.affiliation: Ackerman Academy of Dermatopathology, New York, New York; Department of Dermatology, First Hospital of Jilin University, Changchun, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Biostatistics and Cancer Epidemiology, National Cancer Institute, Cairo University, Cairo, Egypt.
authors.forename: AbdAllah
authors.initials: A
authors.lastname: Gad
authors.affiliation: Dermpath Diagnostics New York, Port Chester, New York.
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Kwon
authors.affiliation: Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina, Charleston, South Carolina. Electronic address: elstond@musc.edu.
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Elston
mesh_terms: D003176:Complement C3 / Q000032:analysis; D019085:Fluorescent Antibody Technique, Direct; D018859:Hair Follicle / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis*; D008178:Lupus Erythematosus, Cutaneous / Q000175:diagnosis* / Q000276:immunology; D012189:Retrospective Studies; D012627:Sebaceous Glands / Q000276:immunology*; D012680:Sensitivity and Specificity; D013545:Sweat Glands / Q000276:immunology*
chemical_list: D003176:Complement C3; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: IgM; cutaneous lupus erythematosus; direct immunofluorescence; hair follicle; immune-mediated dermatoses; lupus band test; sweat gland