Paracortical hyperplasia of superficial lymph nodes in a new mutant strainof hairless rats (ISh): A lesion similar to human dermatopathic lymphadenopathy

The dermal histology and the regional draining superficial lymph node of a new mutant strain of hairless rats (ISh) were investigated. The homozygote ISh rat was characterized as having naked and wrinkled skin. The comedo-lik e cysts in the skin resembled human acne and vulgaris. Histopathologically, many Langerhans' cells positive for anti-protein kinase C type II antibody (PKC-II) were recognized in the epidermis. The superficial lymph nodes wer e significantly larger than those of the heterozygote. The paracortex of th ese lymph nodes was expanded and the number of Langerhans' cells mainly inc reased in these areas. These lymph node lesions were similar to those of hu man dermatopathic lymphadenopathy. The ISh rats should be a very useful ani mal model for studying dermatopathic lymphadenopathy in humans. Furthermore , they may be a valuable animal model for investigating the mechanisms of n ot only maturation, movement and migration of Langerhans' cells, but also o f their function for antigen presentation.