Cb. Harmon et al., DETECTION OF CIRCULATING T-CELLS WITH CD4(-) IMMUNOPHENOTYPE IN PATIENTS WITH BENIGN AND MALIGNANT LYMPHOPROLIFERATIVE DERMATOSES()CD7(), Journal of the American Academy of Dermatology, 35(3), 1996, pp. 404-410
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 th
e percentage of CD4(+)CD7(-) cells and the expression of pan-TT-cell a
ntigens in blood lymphocytes from 31 patients with benign dermatoses w
ith 35 patients who had CTCL. Methods: The patients with CTCL were cla
ssified as follows: 10 with mycosis fungoides (MF), seven with pre-Sez
ary syndrome (pre-SS), and 18 with Sezary syndrome (SS). Flow cytometr
y was used to determine the percentage of CD4(+)CD7(-) cells and the C
D4/CD8 ratio and to detect aberrant expression of the pan-T-cell antig
ens CD2, CD3, and CD5. Results: We found a mean of 5.8% CD4(+)CD7(-) c
ells 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
beni,on dermatoses (p < 0.01); no difference was found between patien
ts with benign dermatoses and those with MF (p = 0.80). The mean CD4/C
D8 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 d
ermatoses (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. Conclusion: Small n
umbers of CD4(+)CD7(-) cells can be found by flow cytometry in patient
s 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-cel
l antigen expression is commonly observed in patients with SS but not
in patients with a benign dermatosis.