The correlation between serum complement levels and clinical presentation in Egyptian immune thrombocytopenia patients.

Background: Immune thrombocytopenia (ITP) is an autoimmune condition characterized by low platelet count and increased risk of bleeding. Several pathophysiological processes contribute to the disease, including complement activation by autoantibodies bound to platelet surfaces. This study aimed to assess complement levels in ITP patients and determine their correlation with clinical presentation and disease severity.

Patients and methods: This case-control study enrolled 40 patients (both sexes, aged 18-40 years) with primary ITP and 40 healthy controls. All participants underwent a comprehensive health assessment, thorough physical examination, laboratory investigations, and abdominal ultrasound. These included a complete blood count (CBC) with blood film, renal and hepatic function tests, hepatitis B surface antigen (HBsAg), hepatitis C virus antibodies (HCV-Abs), human immunodeficiency virus (HIV) antibodies, hepatitis B core antibody (HBcAb), C-reactive protein (CRP), antinuclear antibody (ANA), thyroid-stimulating hormone (TSH), erythrocyte sedimentation rate (ESR), serum complement levels (C3 and C4), and Helicobacter pylori antigen in stool.

Results: Mean C3 and C4 levels were significantly lower in patients with ITP than in healthy controls. A statistical significant negative correlation was found between CRP and C4 levels in ITP patients. However, no statistically significant relationship was observed between C3 and C4 levels and platelet count in ITP patients, regardless of the presence of bleeding complications.

Conclusion: Complement levels were significantly lower in patients with ITP than in healthy controls. Complement levels were also significantly lower in treatment-naïve patients than in patients who received treatment. Therefore, complement levels could serve as a valuable laboratory test for disease activity.