Alterations of skin innate immunity in lymphedematous limbs: Correlations with opportunistic diseases

Lymphedematous areas are sites of regional immune destabilization depicting a typical example of an immunocompromised cutaneous district (ICD). This study evaluates the expression of some components of the skin innate immunity on lymphedematous limbs with the aim to clarify some facets of the ICD. Patients selected underwent two skin biopsies: One was obtained from the limb affected by lymphedema, another from the contralateral healthy limb. Expression of some components of the skin innate immunity was analyzed by reverse transcription-polymerase chain reaction. Stronger gene expression of Toll-like receptor 2 (TLR-2), human β-defensin 2 (HBD-2), desmoglein 1, desmoglein 3, matrix metallopeptidase 9 (MMP-9), and interleukin 10 (IL-10) was found in keratinocytes derived from the affected limb compared with that of keratinocytes derived from contralateral healthy limb. Downregulation of survivin and vasoactive intestinal polypeptide (VIP) gene expression was found in the affected limbs. No induction of IL-1α and tumor necrosis factor α (TNF-α) was detectable in keratinocyte cultures obtained from both lymphedematous and normal limbs. Different phases and components of skin innate immunity turned out to be altered in the lymphedematous sites. Molecular alterations were similar in all patients recruited in the study. These changes might favor the local appearance or progression of opportunistic diseases such as tumors, infections, and immune-mediated skin disorders.