Kininogens and kallikrein in pruritic papular eruption

Pruritic papular eruption (PPE) is a common inflammatory cutaneous lesion observed only in HIV/AIDS patients. Since kinin is an important mediator in inflammation, we evaluated the levels of total kininogen (TKg), low and high molecular weight kininogen (LKg and HKg, respectively) and the activity of kallikrein in plasma of 11 patients (median age = 31.4) with AIDS and PPE (PPE+), eight patients (median age = 31.5) with AIDS without PPE (PPE-) and in 12 control individuals (median age = 32.9) with anti-HIV negative serum. Kininogens were measured by ELISA and expressed in median (m) of BK Equivalent/ml plasma and the kallikrein by its activity upon selective chromogenic substrate, and expressed as U kallikrein/ml of plasma. TKg or LKg concentrations in PPE+ patients (m = 4.11 and 4.5) and in PPE- patients (m = 6.23 and 4.54) were significantly higher when compared to control (m = 2.10 and 1.17). Compared to controls PPE- patients presented similar values of HKg (m = 0.78 and 0.61), whereas PPE+ patients presented undetectable values. Plasma kallikrein activity was significantly decreased in PPE+ and PPE- (m = 0.6 and 0.89, respectively) when compared with control individuals (m = 2.23).