European Journal of Dermatology


Profiling lymphocyte subpopulations in peripheral blood under efalizumab treatment of psoriasis by multi epitope ligand cartography (MELC) robot microscopy Volume 16, numéro 6, November-December 2006

Clinic for Dermatology and Venereology, Otto-von-Guericke-University, Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, GermanyFax: (+49) 391 67 15283, MelTec GmbH & Co. KG, SkinSysTec GmbH, ZENIT Technology Park, Leipziger Str. 44, D-39120 Magdeburg, Germany

CD11a-blocking efalizumab has recently been approved as a systemic treatment of moderate to severe chronic plaque psoriasis. When treating 6 psoriasis patients with efalizumab over 12 weeks in the present study, we observed an overall good tolerability and 5 treatment responders characterized by a decrease of PASI from 21.3 ± 5.4 to 3.9 ± 0.6. The accompanying significant increase of peripheral blood lymphocytes from 1.9 ± 0.7 to 4.3 ± 1.0 × 10 9/L (p < 0.05) was analyzed by multi epitope ligand cartography (MELC) robot microscopy. Thereby a high-dimension simultaneous multiplex immunophenotyping was pursued using 39 fluorophore-labeled antibodies including labeled efalizumab and 3 other affinity reagents such as lectins. Due to efalizumab treatment there was a substantial decrease of the cellular expression of CD11a (detected by mab clone 25.3.1) and efalizumab binding sites (EfaBSs). This was paralleled by an increase of the number of EfaBS and EfaBS + lymphocytes by a factor of 2.4× and 2.2×, respectively. The latter effect was mainly derived from a subpopulation showing a low degree of EfaBS expression. Efalizumab treatment led furthermore to an increase of the numbers of CD3 +, CD4 +, CD8 +, CD44 +, CD45 +, CD45R0 +, CD45 RA +, CD52 +, CD58 +, CD247 +, HLA-DR + and Sambucus nigra lectin-reactive lymphocytes (by factors from 2.0 to 3.3×). In terms of a combinatorial molecular phenotype we identified a CD3 +/CD4 +/CD44 +/CD52 + lymphocyte subpopulation which accumulated most predominantly from 0.824 ± 0.270 × 10 9/L up to 1.616 ± 0.152 × 10 9/L under efalizumab treatment (p < 0.01). Thus, the current study extends the knowledge of efalizumab-dependent perturbations of recirculating blood lymphocyte subpopulations in psoriasis patients.