Cell-mediated immunity, assessed by response to dinitrochlorobenzene (DNCB), is diminished in patients with squamous cell carcinoma or dysplasia.1 Responses to DNCB are impaired during psoralen–UV-A photochemotherapy (PUVA), although they are fully restored 6 weeks after treatment.2 High-dose PUVA is associated with the development of lentigines, keratoses, or squamous cell carcinoma in most subjects.3 In this study, DNCB responses were determined in patients previously exposed to high-dose PUVA.
Ibbotson SH. Experimental Contact Sensitivity in Patients With Previous Exposure to High-Dose PUVA Photochemotherapy. Arch Dermatol. 2001;137(3):381-383. doi: