Telomerase activity is spontaneously increased in lymphocytes from patients with atopic dermatitis and correlates with cellular proliferation

Telomerase is a ribonucleoprotein enzyme involved with cellular proliferati on and cellular senescence. The aim of the present study was to investigate telomerase activity in lymphocytes from patients with atopic dermatitis (A D) and to observe its regulation of cellular proliferation. peripheral bloo d mononuclear cells (PBMC) were isolated from 15 patients with AD and 13 he althy donors. Cells were stimulated with purified protein derivative (PPD) of tuberculin (10 mu g/ml), interleukin 2 (IL-2) (100 U/ml), anti-CDS monoc lonal antibody (anti-CD3) (1 mu g/ml), anti-CD3 plus IL-2, and staphylococc al enterotoxin A (SEA) (0.1 mu g/ml). Telomerase activity was measured by t he telomeric repeat amplification protocol-based telomerase polymerase chai n reaction enzyme-linked immunosorbent assay at 0 and 72 h of incubation. I n addition, DNA synthesis of the cells was assayed using H-3-thymidine inco rporation. We found that telomerase activity in non-stimulated PBMC from pa tients with AD was significantly up-regulated without any stimulation durin g the 72 h of in vitro incubation. The most potent stimulator of telomerase activity was SEA, followed by anti-CD3 plus IL-2, anti-CD3 alone, and PPD. IL-2 did stimulate telomerase activity and DNA proliferation with increasi ng dosage of IL-2. The DNA proliferation was paralleled by increase in telo merase activity. There was no significant difference between telomerase act ivity in stimulated lymphocytes from AD patients and normal donors, but the relative increase in telomerase activity tended to be less in AD patients. A spontaneously higher telomerase activity in lymphocytes from AD patients could indicate that T lymphocytes are already stimulated in vivo or that a population of T cells in peripheral blood exhibits an increased telomerase activity compatible with cellular immaturity. (C) 1999 Elsevier Science Ir eland Ltd. All rights reserved.