[Detection of specific IgG and its specific circular immune complex in the diagnosis of tuberculosis]

Area of Science:

• Immunology
• Infectious Diseases
• Diagnostic Methods

Context:

• Tuberculosis (TB) diagnosis remains a global health challenge, requiring sensitive and specific immunological markers.
• Existing diagnostic methods for pulmonary and extrapulmonary tuberculosis, as well as associated autoimmune conditions, need refinement.
• Evaluating novel biomarkers for tuberculosis detection is crucial for effective patient management and public health.

Purpose:

• To investigate the diagnostic utility of PPD-C IgG and PPD-C IgG within circulating immune complexes (CIC) for tuberculosis.
• To compare the sensitivity and specificity of these markers in tuberculosis patients, lung cancer patients, and healthy controls.
• To determine if PPD-C IgG on CIC offers superior diagnostic value for tuberculosis.

Summary:

• Enzyme-linked immunosorbent assay (ELISA) was used to measure PPD-C IgG in serum and CIC from 50 tuberculosis patients, 20 lung cancer patients, and 30 normal subjects.
• Positive rates for serum PPD-C IgG were 62% (TB), 5% (LC), and 6.7% (normal).
• Positive rates for PPD-C IgG in CIC were significantly higher: 86% (TB), 10% (LC), and 6.7% (normal), with 86% sensitivity and 92% specificity, suggesting its diagnostic value.

Impact:

• PPD-C IgG present in circulating immune complexes demonstrates higher diagnostic accuracy for tuberculosis.
• This finding suggests that CIC-associated PPD-C IgG could be a more valuable immunological marker for tuberculosis diagnosis.
• Further research into CIC-based diagnostics may lead to improved tools for identifying tuberculosis and related conditions.