Detection of circulating T cells with CD4+CD7- immunophenotype in patients with benign and malignant lymphoproliferative dermatoses.
BACKGROUND
Cutaneous T-cell lymphomas (CTCLs) are malignancies of CD4+ T cells that involve the skin. CD4+CD7- cells may represent a malignant population in CTCL.


OBJECTIVE
Our purpose was to compare the percentage of CD4+CD7- cells and the expression of pan-T-cell antigens in blood lymphocytes from 31 patients with benign dermatoses with 35 patients who had CTCL.


METHODS
The patients with CTCL were classified as follows: 10 with mycosis fungoides (MF), seven with pre-Sézary syndrome (pre-SS), and 18 with Sézary syndrome (SS). Flow cytometry was used to determine the percentage of CD4+CD7- cells and the CD4/CD8 ratio and to detect aberrant expression of the pan-T-cell antigens CD2, CD3, and CD5.


RESULTS
We found a mean of 5.8% CD4+CD7- cells for the 16 normal control subjects and 9.3% for the benign cases (p = 0.13). The patients with pre-SS and SS had a higher percentage of CD4+CD7- cells (22.4% and 35.5%, respectively) than patients with benign dermatoses (p < 0.01); no difference was found between patients with benign dermatoses and those with MF (p = 0.80). The mean CD4/CD8 ratio was 3.1 for the normal control subjects compared with 7.4 for the patients with benign dermatoses (p < 0.01). Patients with SS had a ratio of 49, which was higher than the ratio for those with benign dermatoses (p < 0.01); however, the ratio for patients with MF and pre-SS did not differ from that of the group with benign dermatoses (p = 0.71 and 0.55, respectively). Aberrant CD2, CD3, or CD5 expression was observed in 66% of patients with SS, 29% with pre-SS, 30% with MF, but in none of the patients with a benign dermatosis.


CONCLUSIONS
Small numbers of CD4+CD7- cells can be found by flow cytometry in patients with a benign dermatosis and in normal control subjects. This T-cell subset is expanded in pre-SS and SS but not in MF. Aberrant pan-T-cell antigen expression is commonly observed in patients with SS but not in patients with a benign dermatosis.
Harmon
C B
CB
Department of Dermatology, Mayo Clinic, Rochester, MN 55905, USA.
Witzig
T E
TE
Katzmann
J A
JA
Pittelkow
M R
MR
D019011:Antigens, CD7 / Q000032:analysis*; D018801:CD2 Antigens / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis*; D016516:CD4-CD8 Ratio; D018956:CD5 Antigens / Q000032:analysis; D003876:Dermatitis, Atopic / Q000097:blood / Q000276:immunology; D003877:Dermatitis, Contact / Q000097:blood / Q000276:immunology; D017484:Dermatitis, Phototoxic / Q000097:blood / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D016410:Lymphoma, T-Cell, Cutaneous / Q000097:blood* / Q000276:immunology; D009182:Mycosis Fungoides / Q000097:blood / Q000276:immunology; D009450:Neurodermatitis / Q000097:blood / Q000276:immunology; D011565:Psoriasis / Q000097:blood / Q000276:immunology; D012751:Sezary Syndrome / Q000097:blood / Q000276:immunology; D012867:Skin / Q000276:immunology; D012871:Skin Diseases / Q000097:blood* / Q000276:immunology; D012878:Skin Neoplasms / Q000097:blood* / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology*
D019011:Antigens, CD7; D018801:CD2 Antigens; D017252:CD3 Complex; D015704:CD4 Antigens; D018956:CD5 Antigens