Single administration of lesion-limited high-dose (TURBO) ultraviolet B using the excimer laser: clinical clearing in association with apoptosis of epidermal and dermal T cell subsets in psoriasis.

Background/purpose: Development of effective therapy for psoriasis is confounded by numerous factors contributing to disease pathogenesis, including pathogenic immunocytes which appear to drive epidermal keratinocyte hyperproliferation. Our objective was to study clinical and biomarker effects of a single dose of TURBO laser UVB (308 nm) applied directly to psoriatic plaques.

Methods: Eighteen patients with chronic plaque psoriasis received a single dose of 10 minimal erythema dose (MED) UVB and were followed for 8 weeks.

Blockade of CD11a by efalizumab in psoriasis patients induces a unique state of T-cell hyporesponsiveness.

Efalizumab (anti-CD11a) interferes with LFA-1/ICAM-1 binding and inhibits several key steps in psoriasis pathogenesis. This study characterizes the effects of efalizumab on T-cell activation responses and expression of surface markers on human circulating psoriatic T cells during a therapeutic trial. Our data suggest that efalizumab may induce a unique type of T-cell hyporesponsiveness, directly induced by LFA-1 binding, which is distinct from conventional anergy described in animal models.

Regulatory T cells in psoriasis.

Psoriasis is a chronic autoimmune disease in which T lymphocytes are thought to be central in the pathogenesis. Recently, a T cell subset population was identified, whose role is to suppress inflammatory responses triggered by T effector cells. T cells in this new population are referred to as T regulatory cells.

Efalizumab (anti-CD11a)-induced increase in peripheral blood leukocytes in psoriasis patients is preferentially mediated by altered trafficking of memory CD8+ T cells into lesional skin.

Therapeutic administration of efalizumab, a humanized antibody to CD11a, induces a marked but reversible increase of peripheral lymphocytes in psoriasis patients. In this study, 13 patients were treated with 12 weekly subcutaneous doses (2 mg/kg/week) of efalizumab, and all 13 patients had increases in leukocyte counts. This increased white blood cell count was mainly due to a 3- to 4-fold increase in the number of circulating CD3(+) lymphocytes during active treatment.