title: Acute erythroderma as an exclusion criterion for idiopathic CD4+ T lymphocytopenia.
abstract: BACKGROUND
  Idiopathic CD4+ T lymphocytopenia is defined as a CD4+ T lymphocytopenia of less than 0.3 x 10(9)/L that is not associated with human immunodeficiency virus, other immunodeficiency, or immunosuppressive therapy. The associated clinical course and laboratory findings are variable. We describe a subset of patients whose peripheral CD4+ T-lymphocytopenia was transient, and suggest a pathomechanism for this phenomenon.
  
  
  METHODS
  We describe three patients with cutaneous T-cell lymphoma, atopic dermatitis, or psoriasis in whom acute erythroderma was concomitant with a peripheral CD4+ T lymphocytopenia that normalized after resolution of the erythroderma. Immunoperoxidase staining of skin biopsy specimens and quantitative estimation of CD4+ T lymphocytes in the cutaneous and peripheral blood compartments demonstrated that the peripheral CD4+ T lymphocytopenia in these cases most probably resulted from sequestration of CD4+ T lymphocytes in the skin. The skin of an erythrodermic patient appears capable of sequestering 10(10) to 10(11) CD4+ T lymphocytes, whereas the peripheral blood compartment contains in the range of 10(9) CD4+ T lymphocytes.
  
  
  CONCLUSIONS
  We propose that CD4+ T lymphocytopenia can occur as a result of acute erythroderma of multiple causes and that acute erythroderma associated with transient CD4+ T lymphocytopenia be considered as an exclusion criterion for idiopathic peripheral blood CD4+ T lymphocytopenia.
authors.affiliation: Department of Dermatology, University of Michigan Medical Center, Ann Arbor.
authors.forename: T W
authors.initials: TW
authors.lastname: Griffiths
authors.forename: S R
authors.initials: SR
authors.lastname: Stevens
authors.forename: K D
authors.initials: KD
authors.lastname: Cooper
mesh_terms: D000328:Adult; D000368:Aged; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D003873:Dermatitis, Exfoliative / Q000097:blood / Q000150:complications*; D006801:Humans; D008297:Male; D018344:T-Lymphocytopenia, Idiopathic CD4-Positive / Q000097:blood / Q000150:complications*