Biomarkers of the Humoral Immune System and Inflammation Assessed

The immune system is a complex set of physiological mechanisms that defend the body against infectious agents (bacteria, viruses, parasites, fungi) that can cause disease. Immunological surveillance can also detect and eliminate cancer cells.

Macrophages conduct the defense against bacteria and fungi, but also by acting as antigen-presenting cells to trigger adaptive immunity and as effector cells in antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Cytokines and chemokines released by macrophages in response to pathogen constituents initiate the process known as inflammation.

Medical Scientists at the King’s College London (London, UK) and their colleagues explored the reciprocity between the humoral immune system and inflammation and assessed how external socio-demographic factors may influence these interactions. Inclusion criteria for their study were defined as follows: all individuals aged 20 or older and with the following measurements (n = 5513): immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), C-reactive protein (CRP), haptoglobin, albumin, white blood cells (WBC), serum iron (SI) and total iron-binding capacity (TIBC).

The quantitative determination of IgA, IgG and IgM was done with a turbidimetric determination with reagents (DAKO, Glostrup, Denmark) using a HITACHI 911 automatic analyzer (Boehringer, Mannheim, Germany). Serum CRP and haptoglobin was measured with an immunoturbidimetric assay using the fully automated DAX 96 multichannel analyzer (Technicon Instruments Corporation, Tarrytown, NY, USA). Albumin was measured using the bromocresol green method. Leukocytes were measured by routinely used hematology analyzers (STKS Haematology System from Coulter Corporation, Hialeah, FL, USA).

The team reported that frequently used serum markers for inflammation, CRP, haptoglobin and white blood cells, correlated together. Hierarchical clustering and principal component analysis confirmed the interaction between these main biological responses, showing an acute response component (CRP, Haptoglobin, WBC, IgM) and adaptive response component (Albumin, Iron, TIBC, IgA, IgG). A socioeconomic gradient associated with worse health outcomes was observed, specifically low educational level, older age and male sex were associated with serum levels that indicated infection and inflammation.

The authors concluded that their findings indicate that serum markers of the humoral immune system and inflammation closely interact in response to infection or inflammation. Clustering analysis presented two main immune response components: an acute and an adaptive response, comprising markers of both biological pathways. Future studies should shift from single internal marker assessment to multiple humoral and inflammation serum markers combined, when assessing risk of clinical outcomes such as cancer. The study was published on September 6, 2021 in the journal BMC Immunology.

Related Links:

King’s College London >>> www.kcl.ac.uk
DAKO >>> www.dako.de
Boehringer
Technicon Instruments
Coulter Corporation