PSORIATIC KERATINOCYTES EXPRESS HIGH-LEVELS OF NERVE GROWTH-FACTOR

Many investigators have reported proliferation of terminal cutaneous n erves and upregulation of various neuropeptides (substance P, vasoacti ve intestinal polypeptide, calcitonin gene-related peptide) in psoriat ic lesions. Nerve growth factor promotes growth of nerves and causes u pregulation of neuropeptides Like substance P and calcitonin gene-rela ted peptide. In this study we investigated the expression of nerve gro wth factor in psoriatic lesions, non-lesional psoriatic skin, lichen p lanus and normal control skin. Immunoperoxidase staining was applied o n cryosections prepared from snap-frozen biopsy specimens. The primary antibody used was a polyclonal anti-NGF-beta antibody. Nerve growth f actor was detected only in the keratinocytes. In psoriatic tissue the number of keratinocytes per square millimeter of epidermis positive fo r nerve growth factor was 84.7 +/- 46.3 compared to 44.8 +/- 29.9, 18. 9 +/- 11.8 and 7.5 +/- 16.9, respectively, in non-lesional psoriatic s kin, normal skin and lichen planus. Increased expression of nerve grow th factor substantiates larger numbers of terminal cutaneous nerves an d upregulations of substance P and calcitonin gene-related peptide in psoriatic lesions. In addition, nerve growth factor is mitogenic to ke ratinocytes, activates T-lymphocytes and can induce migration of infla mmatory cellular infiltrates, histological features characteristic of psoriasis.