Ultrastructural and cell surface changes of human psoriatic skin following Goeckerman therapy.

Ultrastructural and cell surface studies of skin in psoriatic patients prior to and after Goeckerman therapy (crude coal tar and UVB-light) have demonstrated significant cellular changes following this treatment: hyperactivity of melanocytes with melanosome polymorphism, increase of desmosomes, tonofilaments, keratohyaline granules, a decrease in mitochondria, keratinosomes, polysomes, dark cells and a reduction in size of nuclei and nucleoli. The enlargement of intercellular spaces and the redundancy of basement membrane were also reduced. Langerhans cells were moderately decreased and exhibited a normal ultrastructural pattern. No significant changes in cutaneous nerve distribution or morphology were observed in these cases. Scanning electron microscopy following treatment revealed a regular surface and orientation of corneocytes, with flattened surfaces; and a reduction of their ridges on the surfaces, as well as of the intercellular spaces and red blood cells. These findings indicate that Goeckerman therapy restored the ultrastructural and cell surface pattern in the psoriatic skin by inducing orthokeratinogenesis, development of the tonofibrillar-desmosome system, and decrease in mitochondria, nuclei and nucleoli.