An immunohistopathologic study in cutaneous necrotizing vasculitis

In order to investigate the importance of timing in the immunophenotypical characteristics of the inflammatory infiltrate and in the adhesion molecule s expression in cutaneous necrotizing study. An avidin-biotin-streptavidin peroxidase technique was performed on 21 lesional skin biopsy specimens obt ained sequentially at 0 to 24, 72 and 120 hours from seven patients with a CNV presenting as palpable purpura. A panel of monoclonal antibodies specif ic for inflammatory cells (T lymphocytes, polymorphonuclear leukocytes, mac rophages, dendritic cells) and different adhesion molecules (E-selectin, IC AM-1, VCAM-1, LFA-1, VLA-4) was used. Moreover, HECA-450 monoclonal antibod y was used to identify cutaneous lymphocyte antigen (CLA) in the inflammato ry infiltrate. In all cases, polymorphonuclear leukocytes predominated in t he early phase of CNV and their number decreased significantly with rime (p =0.0001). The T lymphocytes were present from the beginning and their numbe r remained stable or increased slightly in time (p=0.1), thus becoming pred ominant in the perivascular infiltrate in older lesions. Macrophages were s cattered on inter stitium since the early phase and they showed a time-depe ndent increase (p=0.0003). E-selectin (ELAM-1) expression was detected at t he first biopsy and it decreased depending on the age of the evolving vascu litis (P=0.0033). The expression of CLA decreased also with time in 5 of th e 7 cases (p=0.0001). Our study supports the existence of an unique histopa thologic pattern in CNV in which the inflammatory infiltrate varies with ti me at the expense Of the number of polymorphonuclear cells and macrophages.