Proliferation of B-lymphocytes in inflammatory and hematological diseases

Introduction. A proliferation-inducing ligand is a membrane binding protein that represents one of the main survival factors for immature, naive and activated B-cells, and is involved in the global immune response. The objective of this study was to determine whether plasma levels of a proliferation-inducing ligand may be used to assess the proliferation of B-lymphocytes in patients with bacterial infections, B-cell malignancies and autoimmune inflammatory disorders. Material and Methods. The study included 91 patients divided into three groups and 30 blood donors assigned to the control group. Group 1 included 34 patients with bacterial infections confirmed by microbiology and/or radiology diagnostic tests; group 2 included 32 patients with B-cell malignancies; and group 3 included 25 patients with autoimmune inflammatory diseases. All plasma samples were assayed for a proliferation-inducing ligand using enzyme-linked immunosorbent assay. The differences between groups were examined by one-way analysis of variance test and post hoc analysis. Results. One way analysis of variance test showed a statistically significant difference in concentrations of a proliferation-inducing ligand in the examined groups. The highest mean value of a proliferation-inducing ligand was found in patients with established bacterial infections (x = 8,294 ng/ml). Post hoc analysis showed that a proliferation-inducing ligand levels in the plasma samples of patients with bacterial infections were significantly higher than in healthy controls, and patients with hematological and autoimmune diseases, respectively. Conclusion. B-cell proliferation was increased in patients with bacterial infections in regard to patients with other disorders. Therefore, a proliferationinducing ligand can be used to differentiate bacterial infections from other inflammatory disorders and may be helpful in decision making whether to start antibiotic treatment or not.