Related Experiment Video
Updated: Dec 2, 2025
Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells
Published on: January 29, 2014
Immune dyscrasia in adult growth hormone deficiency: Evaluation of hemolytic complement activity (CH50) and IgG
Edoardo Vergani1, Carmine Bruno1, Cecilia Napodano2
1Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
Insights
Adult growth hormone deficiency (aGHD) shows altered immunoglobulin G (IgG) subclass production and higher CH50 complement activity compared to healthy individuals. This suggests a specific immune dyscrasia in aGHD patients.
Area of Science:
- Immunology
- Endocrinology
Background:
- Adult growth hormone deficiency (aGHD) is a chronic inflammatory condition.
- Inflammatory biomarkers in aGHD are not well-understood.
- The classical complement pathway (CH50) is implicated in inflammatory diseases.
Purpose of the Study:
- To investigate CH50 and immunoglobulin G (IgG) subclass levels in adults with aGHD.
- To compare these immune markers between aGHD patients and healthy controls.
Main Methods:
- A case-control observational study involving 18 aGHD patients and 20 healthy controls.
- Diagnosis of GHD confirmed via dynamic testing (GHRH + arginine).
- Evaluation of hormonal, metabolic, CH50, and IgG subclass parameters.
Main Results:
- Significantly higher levels of IgG1 and IgG2 in healthy controls compared to aGHD patients.
- Trends towards higher IgG3 and IgG4 in controls, though not statistically significant.
- Significantly elevated CH50 levels observed in aGHD patients.
Conclusions:
- Findings suggest a dyscrasia in IgG subclass production in aGHD.
- Elevated CH50 levels in aGHD patients indicate complement pathway activation despite decreased IgG levels.
Abstract:
CH50 is a screening assay for the activation of the classical complement pathway, the immunoglobulins-mediated one, activated in several inflammatory diseases. Adult growth hormone deficiency (aGHD) is recognized as a chronic inflammatory condition, although poorly evaluated under the profile of inflammatory biomarkers. The aim of this case-control observational study is to analyze CH50 and immunoglobulins G (IgG) subclasses production in aGHD, comparing this condition to healthy controls. 38 subjects were included and divided as follows: aGHD (n = 18, 6 females and 12 males); healthy controls (n = 20, 10 females and 10 males). GHD was diagnosed with dynamic test using Growth Hormone-Releasing Hormone (GHRH 50 μg i.v. + arginine 0,5 g/Kg), with a peak GH response < 9 μg/L when BMI was <30 kg/m2 or < 4 μg/L when BMI was >30 kg/m2. The two groups were evaluated for hormonal and metabolic parameters, CH50 and IgG subtypes. IgG1 and IgG2 were significantly higher in controls than in aGHD, while IgG3 and IgG4 showed a trend to higher levels in controls, although not significant. Furthermore, CH50 levels were significantly higher in aGHD. These data substantiate the hypothesis of a dyscrasia in IgG subclasses production in aGHD. As IgG levels decrease, CH50 levels do not.
