Cerebrospinal fluid T-regulatory cells recognize Borrelia burgdorferi NAPA in chronic Lyme borreliosis.

The NapA protein of B. burgdorferi is essential for the persistence of spirochetes in ticks. One of the most intriguing aspects of NapA is its potential to interfere with the host immune system. Here, we investigated the role of the acquired immune responses induced by NapA in the cerebrospinal fluids (CSF) of patients with chronic Lyme borreliosis. We evaluated the cytokine profile induced in microglia cells and CSF T cells following NapA stimulation. We report here that NapA induced a regulatory T (Treg) response in the CSF of patients with chronic Lyme borreliosis and it is able to expand this suppressive response by promoting the production of TGF-beta and IL-10 by microglia cells. Collectively, these data strongly support a central role of NapA in promoting both Treg response and immune suppression in the CSF of patients with chronic Lyme borreliosis and suggest that NapA and the Treg pathway may represent novel therapeutic targets for the prevention and treatment of the disease.

Analysis of the immune status in Latvian Chernobyl clean-up workers with nononcological thyroid diseases.

The aim of the present work was to characterize the immune status of 385 individuals who participated in the 1986-90 clean-up work of the after effects of the Chernobyl nuclear power plant explosion. Fifty-nine Chernobyl clean-up workers developed the most common thyroid diseases; euthyroid nodular and diffuse goiter; 47 healthy blood donors were taken as controls. The levels of immunoglobulins (IgA, IgG and IgM), the numbers of peripheral blood leukocytes, lymphocytes, monocytes, T lymphocytes and their subpopulations (CD3+, CD4+, CD8+), B lymphocytes (CD19+), natural killer (NK) cells (CD16+), classical and alternative pathway activity of complement (CH50, APH50), the C3 split product C3d, and neutrophil phagocytosis were determined in the peripheral blood. We found a significantly decreased number of CD16+ cells (natural killer), of CD4+ and CD8+ T lymphocytes, a reduced neutrophil phagocytic activity as well as a significant complement activation in Chernobyl clean-up workers with and without thyroid diseases when compared with normal levels and those in the control group. In addition, the number of CD3+ and CD4+ cells was significantly higher in patients with nodular goiter when compared with that in patients with diffuse goiter. Levels of IgG and numbers of monocytes were significantly decreased in persons who worked in Chernobyl in 1986 during the first 2 months after the accident (with maximal radiation exposure) but were without correlation to thyroid disorders. Our results clearly reflect an impaired immune system in the Chernobyl clean-up workers even 10-14 years after the nuclear accident.