Resident lymphocytes in the dermis of the normal dorsolateral thoracic skin of alpacas

BACKGROUND: Small numbers of resident T lymphocytes are present in the dermis of normal skin of humans, cattle and sheep. HYPOTHESIS/OBJECTIVES: We wanted to determine the prevalence, numbers and immunophenotype of lymphocytes in the dermis of healthy skin from alpacas. ANIMALS: Skin biopsy specimens were collected from the dorsolateral thorax of 31 alpacas with normal skin. METHODS: Skin biopsy specimens were evaluated for the prevalence and numbers of CD3+ and CD79a+ lymphocytes. RESULTS: Resident CD3+ and CD79a+ lymphocytes were found around the superficial and deep dermal blood vessels. The CD3+ lymphocytes were more numerous than CD79a+ lymphocytes. Both CD3+ and CD79a+ lymphocytes were more numerous around superficial dermal blood vessels. CONCLUSIONS AND CLINICAL IMPORTANCE: Resident CD3+ and CD79a+ lymphocytes are present around superficial and deep dermal blood vessels in normal skin from alpacas; hence, the presence of lymphocytes in these locations without obvious features of inflammation must be interpreted cautiously when evaluating skin biopsy specimens from alpacas with skin disease.