Treatment regimen, clinical response, proliferation index and expression of IL2R-α and pY-STAT3, and clonal T-cell populations in the skin lesions before and after antibiotic therapy. (A) Eight CTCL patients were treated for 10 days with IV antibiotics (cephalosporin and metronidazole) and subsequent oral treatment of 14 days with combined amoxicillin and clavulanate. (B) All patients had clinical improvement 2 months after antibiotic treatment. The mSWAT scores dropped after treatment (left). The mSWAT score before treatment differed among the included patients (left). (Right) The subjective patient self-reported evaluations of disease severity according to the VAS. (C-H) Immunohistochemistry of the proliferation index (Ki67 staining), and expression of IL2R-α and pY-STAT3 before and 2 months after initiation of antibiotic treatment in patients 1 and 2 (original magnification ×10). Stainings for patients 3 through 8 are presented in supplemental Figure 1. Images were obtained with a Leica DM2000 microscope equipped with a Leica DFC295 camera, magnification ×100 and LAS v4.6 acquisition software. (I) Sequencing the CDR3 of the TCR-β chain from gDNA from CTCL skin biopsies identified a dominant clonal T-cell population in 6 of 8 patients. The frequency of the most dominant TCR clonotype is depicted for each patient (numbered) before and 60 days after initiation of antibiotic treatment. The presence of a dominant T-cell population could not be demonstrated in patients 3 and 7 by TCR sequencing. mSWAT, modified Severity Weighted Assessment Tool; Pt., patient; VAS, visual analog scale.