interleukin-8 and Granuloma--Plasma-Cell

Abnormal wear of cobalt-containing metal-on-metal joints is associated with inflammatory pseudotumours. Cobalt ions activate human toll-like receptor 4 (TLR4), which normally responds to bacterial lipopolysaccharide (LPS) in sepsis. Activation of TLR4 by LPS increases the expression of chemokines IL-8 and CXCL10, which recruit leukocytes and activated T-cells, respectively. This study was designed to determine whether cobalt induces a similar inflammatory response to LPS by promoting the expression of IL-8 and CXCL10. A human monocytic cell line, derived from acute monocytic leukaemia, was treated with cobalt ions and expression of IL-8 and CXCL10 measured at mRNA and protein levels. Cobalt-treated macrophages showed a 60-fold increase in IL-8 mRNA, and an eightfold increase in production of the mature chemokine (both p < 0.001); expression of the CXCL10 gene and protein was also significantly increased by cobalt (both p < 0.001). Experiments were also performed in the presence of CLI-095, a TLR4-specific antagonist which abrogated the cobalt-mediated increase in IL-8 and CXCL10 expression. These findings suggest that cobalt ions induce inflammation similar to that observed during sepsis by the simultaneous activation of two TLR4-mediated signalling pathways. These pathways result in increased production of IL-8 and CXCL10, and may be implicated in pseudotumour formation following metal-on-metal replacement.

Topics: Biomarkers; Cell Line; Chemokine CXCL10; Cobalt; Enzyme-Linked Immunosorbent Assay; Granuloma, Plasma Cell; Hip Prosthesis; Humans; Interleukin-8; Joint Diseases; Lipopolysaccharides; Macrophages; Metal-on-Metal Joint Prostheses; Monocytes; Toll-Like Receptor 4

A 69-year-old woman had plasma cell granuloma of the left middle lobe of the lung. Her symptoms and roentgenologic findings improved with antibiotic treatment. Before treatment, the number of neutrophils and NCA were markedly increased in BAL fluid obtained from the affected region of the left lung and moderately increased in BAL fluid obtained from the nonaffected region of the right lung. The number of neutrophils, the NCA as well as the contents of C5 and C5a des Arg (neutrophil chemotactic factors) in the BAL fluids from both these regions decreased during treatment. These findings suggest that plasma cell granuloma was due to chronic immune and inflammatory reactions in the lung, that neutrophils are involved in development of the symptoms and signs of this disease, and that neutrophil chemotactic factors, including complement-derived factors, are important in neutrophil recruitment at the lesion and in nonaffected parts of the lung.

Topics: Aged; Albumins; Bronchoalveolar Lavage Fluid; Cell Count; Chemotactic Factors; Complement C5; Female; Granuloma; Granuloma, Plasma Cell; Humans; Immunoglobulins; Interleukin-8; Lung Diseases; Neutrophils; Radiography