Background: The association between periodontitis and systemic health is evident; however, until recently, there was a lack of scientific evidence to define the relationship between aggressive periodontitis (AgP) and systemic conditions. The aim of this study was to explore the characteristics of peripheral blood cellular and serum protein parameters in patients with AgP.Methods: Patients with AgP (n = 150) and healthy controls (n = 94) were recruited. Clinical parameters, including probing depth (PD), clinical attachment level (CAL), and percentage of severe sites, were examined. Blood cell variables, including leukocyte, neutrophil, and lymphocyte counts, as well as serum protein parameters, including total protein, albumin, globulin, and albumin/globulin ratio, were analyzed.Results: Elevated neutrophil numbers and serum globulin levels were observed in patients with AgP compared to controls (4.22 ± 1.81 × 10⁹/l versus 3.20 ± 0.91 × 10⁹/l and 29.20 ± 3.75 g/l versus 27.17 ± 3.32 g/l, respectively; P <0.01). Albumin level and albumin/globulin ratio were lower in the AgP group than in the control group (47.65 ± 2.45 g/l versus 48.88 ± 2.13g/l and 1.66 ± 0.24 versus 1.83 ± 0.24, respectively; P <0.01). In the AgP group, neutrophil counts and serum globulin levels were positively correlated with clinical parameters, including mean values for PD, CAL, and percentage of severe sites (P <0.05); the albumin level and albumin/globulin ratio were inversely correlated with the clinical parameters as described above (P <0.05).Conclusions: Patients with AgP may have elevated peripheral leukocyte numbers and serum globulin levels as well as decreased serum albumin levels and albumin/globulin ratios compared to controls. These changes might be associated with the severity of periodontal destruction.