Immune Regulation Patterns in Response to Environmental Pollutant Chromate Exposure-Related Genetic Damage: A Cross-Sectional Study Applying Machine Learning Methods

Exposure to hexavalent chromium damages genetic materials like DNA and chromosomes, further elevating cancer risk, yet research rarely focuses on related immunological mechanisms, which play an important role in the occurrence and development of cancer. We investigated the association between blood chromium (Cr) levels and genetic damage biomarkers as well as the immune regulatory mechanism involved, such as costimulatory molecules, in 120 workers exposed to chromates. Higher blood Cr levels were linearly correlated with higher genetic damage, reflected by urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and blood micronucleus frequency (MNF). Exploratory factor analysis revealed that both positive and negative immune regulation patterns were positively associated with blood Cr. Specifically, higher levels of programmed cell death protein 1 (PD-1; mediated proportion: 4.12%), programmed cell death ligand 1 (PD-L1; 5.22%), lymphocyte activation gene 3 (LAG-3; 2.11%), and their constitutive positive immune regulation pattern (5.86%) indirectly positively influenced the relationship between blood Cr and urinary 8-OHdG. NOD-like receptor family pyrin domain containing 3 (NLRP3) positively affected the association between blood Cr levels and inflammatory immunity. This study, using machine learning, investigated immune regulation and its potential role in chromate-induced genetic damage, providing insights into complex relationships and emphasizing the need for further research.

Decreases in CD8+ T, naive (CD4+CD45RA+) T, and B (CD19+) lymphocytes by exposure to manganese fume

To examine the effects of exposure to manganese (Mn) on the cellular and humoral immune system in men, T lymphocyte subpopulations, B (CD19+) lymphocytes, natural killer (NK) cells, and serum immunoglobulins (i.e., IgG, IgA and IgM) together with total T (CD3+) lymphocytes and total lymphocytes were measured in blood samples from 21 welders mainly exposed to Mn fume with blood Mn (BMn) concentrations of 0.6-2.3 (mean 1.4) microg/dl and 21 healthy controls working in the same factory (BMn concentrations: 0.7 to 1.7, mean 1.1 microg/dl). The workers engaged in welding for 6 to 36 (mean 17) yr. All the study subjects were divided into 3 equally sized groups (n=14 for each group) according to BMn concentrations. Numbers of CD8+ T, total T (CD3+), B (CD19+), and total lymphocytes were significantly lower in high-BMn group than those in low-BMn group; the numbers of CD8+ T lymphocytes were significantly lower in moderate-BMn group compared to low-BMn group. After adjusting for age and smoking, significant inverse correlations between BMn concentrations and CD4+CD45RA+ T, CD4+ T, CD8+ T, CD3+ T, and total lymphocytes were found. We conclude that T lymphocytes, especially CD8+ and CD4+CD45RA+ T lymphocytes, as well as CD19+ B lymphocytes are affected by exposure to Mn fume.

Decreases of natural killer cells and T-lymphocyte subpopulations and increases of B lymphocytes following a 5-day occupational exposure to mixed organic solvents

The authors examined the effects of organic solvents on lymphocyte subpopulations in blood. Natural killer and T-lymphocyte subpopulations and B (CD19+) -lymphocytes were measured with flow cytometry in 16 male rotogravure printers on a Friday and on the following Monday. Numbers of all 3 subpopulations of natural killer cells (i.e., CD57+ CD16+, CD57- CD16+, and CD57+ CD16- cells), 2 subpopulations of T lymphocytes (CD4+ CD45RA+ and total CD8+ cells), and total lymphocytes on Friday were significantly fewer than those found on the following Monday. Conversely, the number of B lymphocytes on Friday was significantly larger than the number on Monday. The number of B lymphocytes was significantly correlated with blood toluene levels on Friday. The alteration in the number of CD57+ CD16+ NK cells from Friday to the following Monday was correlated inversely with the corresponding change in exposure level of toluene on Friday. The authors suggest that the effects of mixed organic solvents (primarily toluene) are recoverable decreases of natural killer cells and T lymphocytes and increases in B lymphocytes.