Up-regulation of CCL20 and its receptor CCR6 in KS samples. (A) Box-whisker plots with 95% confidence intervals for the RNA expression of CCL20, K13, LANA, and CCR6 in KSHV-infected patients' lymph nodes (KS lymph nodes, n = 5) and skin samples (KS skin samples, n = 10) along with corresponding benign lymph nodes (n = 6) and normal skin (n = 10) samples. Box-whisker plot indicates the median expression of respective genes relative to β-actin (line in the box) and their interquartile range (box). The whiskers present an entire range of expression level of indicated genes in a group, the upper value being the largest observation ≥ 75th percentile + 1.5 × (interquartile range), with the lowest value being the smallest observation ≤ 25th percentile − 1.5 × (interquartile range). The RNA was isolated from flash frozen tissues, and the expression levels of the indicated genes were determined by quantitative RT-PCR. The expression levels of CCL20 and its receptor CCR6 were significantly higher in the KS samples compared with corresponding uninfected controls (*P < .05, Mann-Whitney U test). Similarly, the expression level of LANA and K13, 2 key genes of KSHV infectivity, were significantly higher in KS samples than the corresponding healthy skin or lymph node samples (*P < .05, Mann-Whitney U test). (B) Hematoxylin and eosin staining shows the presence of characteristic spindle cells in a KS biopsy specimen. (C) Immunohistochemistry shows the presence of LANA-positive cells with typical brown punctate nuclear staining (black arrows) in the KS lesion. (D) Double immunostaining with LANA and CCL20 antibodies shows that a majority of CCL20-positive cells (red; white arrows) are positive for LANA (brown). (B-D) original magnification ×400.