B cell toll-like receptors with respect to the pathogenesis of Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune immunopathological disease of unknown aetiology. It is characterized by focal lymphocyte infiltration and inflammation in exocrinne glands, involving especially salivary and lacrimal glands. Hypofunction of the glands leads to the decreased glandular secretion together with impaired production of saliva and tears, resulting in dryness of the mouth and eyes (xerostomia and xerophthalmia, respectively). Some of the studies have suggested that Toll-like receptors and B cells play a pivotal role in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and SS etc. Stimulation of B cells via the TLRs pathway leads to several important changes including increase in antibody production, differentiation to plasma cells, cytokine production and up-regulation of molecules essential for antigen presentation to (autoreactive) T cells. Experimental data support the idea that co-engagement of BCR and TLR might be sufficient for B cell activation and lead to the failure of tolerance. In human naive B cells, most TLRs are expressed at very low or undetectable level, but expression of TLR 7 and 9 is rapidly induced by B cell receptor triggering. This review will focus on the possible role of B cells and TLRs signaling in the pathogenesis of SS.

The counter-regulation of atherogenesis: a role for interleukin-33

The recently recognized cytokine interleukin-33 and its receptor ST2 play a favorable role during atherogenesis by inducing a Th1 --> Th2 shift of the immune response. IL-33 also protects the failing human heart from harmful biomechanical forces which lead to cardiomyocyte hypertrophy and exaggerated interstitial fibrosis. IL-33 inevitably displays side effects common to other Th2 cytokines, the most grave of which is a predisposition to allergic reactions. IL-33 is a nuclear transcription factor of endothelial cells. As such, it is abundant in nonproliferating vessels. Its down-regulation is required for angiogenesis, which may be profitable in wound healing or deleterious in tumor growth.

RANK/RANKL expression is induced by cardiac surgical operation

BACKGROUND

Cardiac surgery provokes a systemic inflammatory response in any patient. This complex body reaction involves also RANK/RANKL molecules which have been recently identified as principal regulators of bone metabolism.

AIMS

To follow the changes in the expression of RANK/RANKL molecules on innate immune cells of cardiac surgical patients.

PATIENTS AND METHODS

Twenty-six patients undergoing cardiac surgical were assigned to undergo coronary artery bypass grafting using either cardiopulmonary bypass ("on-pump") or modified "miniinvasive on-pump". The expression of RANK/RANKL was performed by flow cytometry.

RESULTS

Significantly increased expression of RANK on monocytes of "miniinvasive on-pump" patients was found at the 1st, the 3nd, and 7th postoperative days. The similar pattern was found also for monocyte RANKL expression. In addition, RANKL expression was significantly increased at the 3rd postoperative day in "on-pump" patient. No significant differences between "miniinvasive on-pump" and "on-pump" cardiac surgical patients were found.

CONCLUSION

The expression of both RANK and RANKL molecules is significantly enhanced on monocytes of "miniinvasive on-pump" cardiac surgical patients.

Scavenger receptor CD163 and its biological functions

CD163 is a member of scavenger receptor super family class B of the first subgroup. It is mapped to the region p13 on chromosome 12. Five different isoforms of CD163 have been described, which differ in the structure of their cytoplasmic domains and putative phosporylation sites. This scavenger receptor is selectively expressed on cells of monocytes and macrophages lineage exclusively. CD163 immunological function is essentially homeostatic. It also has other functions because participates in adhesion to endothelial cells, in tolerance induction and tissues regeneration. Other very important function of CD163 is the clearance of hemoglobin in its cell-free form and participation in anti-inflammation in its soluble form, exhibiting cytokine-like functions. We review the biological functions of CD163 which have been discovered until now. It seems apparent from this review that CD163 scavenger receptor can be used as biomarker in different diseases and as a valuable diagnostic parameter for prognosis of many diseases especially inflammatory disorders and sepsis.

[Mucosal immunity with emphasis on urinary tract immunity and diabetes]

Protective immune response in urinary tract is frequently impaired in patients with diabetes. Immunity in this mucosal compartment displays unique characteristics; e.g. absence of physiological microflora and lack of mucus. Pathogens are identified by the PRR receptors expressed on both epithelial and immune cells. Inflammatory response characterised by the acumulation ofgranulocytes is followed. Both protective and harm characteristics of inflammatory response are inseparable linked and delineated by gene polymorphisms in PRR receptors.

The expression of CD38 ADP-ribosyl cyclase ectoenzyme in immune cells of cardiac surgical patients

BACKGROUND

This study was aimed at following the changes in the expression of CD38 ADP-ribosyl cyclase ectoenzyme on peripheral blood immune cells of patients undergoing cardiac surgical operations.

PATIENTS AND METHODS

The expression of CD38 on lymphoid and myeloid cells was determined by immunofluorescence and flow cytometry in forty cardiac surgical patients assigned to surgery either using ("on-pump", n=20) or without the use ("off-pump", n=20) of cardiopulmonary bypass.

RESULTS

There was a very rapid upregulation of CD38 expression in "on-pump" patients, becoming significant at declamping of aorta (p<0.01) for myeloid cells and at the weaning from CPB (p<0.001) for lymphocytes. The increased expression of CD38 on lymphocytes in "off-pump" patients was prolonged for the entire observation period. However, significant differences in the expression of CD38 between "on-pump" and "off-pump" patients were not found either in lymphoid or myeloid cells.

CONCLUSION

CD38 expression in immune cells of cardiac surgical patients is upregulated early during surgery, providing additional activation stimuli to the cell substrate of the inflammatory response induced by cardiac surgery.

The effect of cardiac surgery on peripheral blood lymphocyte populations

BACKGROUND

Cardiac surgery using cardiopulmonary bypass (CPB) is associated with some adverse postoperative complications caused by an altered immune response. An alternative approach to cardiac surgery, operating without the use of CPB (i.e. off-pump surgery), seems to display less adverse impacts on the immune response.

PATIENTS AND METHODS

Peripheral blood lymphocytes in 40 patients undergoing cardiac surgery either with CPB ("on-pump") or without CPB ("off-pump") were followed using flow cytometry. The samples of peripheral blood were taken at five intervals: preoperatively, after termination of the surgery, on the first, on the third and on the seventh postoperative day, respectively.

RESULTS

The most substantial changes appeared on the first postoperative day in both subgroups of patients. While the percentage of both total T cells and CD4+ T cells were decreased, the percentage of HLA-DR+ activated lymphocytes was increased. These changes were more profound in the "on-pump" subgroup compared to the "off-pump" subgroup.

CONCLUSION

Our results may suggest that the "off-pump" surgical approach reveals less adverse impact on adaptive immune responses.

[Transcription factor KLF2 (Krüppel-like factor 2) and natural defence of vascular endothelium]

Vascular endothelium, monocytes and T-lymphocytes belong to the key cellular populations, which take an active part in the host's defence reactions. A successful course of these reactions is determined by a meticulous control of all phases since the very first steps until final healing of all incurred wounds. Any failure of the control mechanisms may lead to the development of chronic inflammatory diseases with an autoimmune component, such as the rheumatoid arthritis or atherosclerosis. An inflammatory reaction which is already under way is regulated by anti-inflammatory cytokines. However, of equal importance is the maintenance of cellular participants of inflammatory reactions in a quiescent state while no pro-inflammatory stimuli are present. One of the most important endogenous mediators, which prevent a self-initiated activation of endothelial cells, monocytes and T-lymphocytes, is represented by the transcription factor Krüppel-like factor 2. Its impact on the mentioned cells is almost identical with the so-called pleiotropic effects of inhibitors of the enzyme HMG CoA reductase or statins. This review article offers an insight into basic preventive mechanisms exerted by KLF2, notably those related to atherosclerosis.

Expression of an activated form of integrin beta2 chain CD18 in cardiac surgical operations

BACKGROUND

Myeloid cells are extensively activated in patients undergoing cardiosurgical operations. It is supposed that this activation is more profound in patients operated with cardiopulmonary bypass (CPB) ("on-pump") in comparison with patients operated without CPB ("off-pump").

AIMS

To evaluate changes in the expression of a novel activation marker expressed on myeloid cells recognized by MEM-148 antibody.

PATIENTS AND METHODS

The expression of MEM-148 positive myeloid cells was evaluated by flow cytometry in 40 patients who underwent coronary artery bypass surgery (CABG) randomly assigned to "on-pump" or "off-pump" technique.

RESULTS

The relative and absolute number of MEM-148 positive myeloid cells is significantly diminished during "on-pump" surgery. A significant increase in their number in postoperative period in both "on-pump" and "off-pump" patients was found. There were no significant differencies between "on-pump" and "off-pump" patients.

CONCLUSIONS

The very trauma of surgery seems to be more relevant in starting on activation of myeloid cells them CPB itself.

Essential PTX3 biology (not only) for cardiologists and cardiac surgeons

Inflammation has been recognized to form an integral part of the atherosclerotic process. Much consideration has been given lately to the role played in atherogenesis by C-reactive protein (CRP). Although not accepted unequivocally, CRP appears to be not only a marker, but also an active mediator of the atherosclerotic process. Pentraxin 3 (PTX3) is a newly identified acute phase reactant which shares some structural and some functional properties with CRP. On the other hand, pentraxin 3 displays unique biological properties of its own, including a possible role in the pathogenesis of cardiovascular diseases and in processes accompanying the natural evolution of surgical wounds. This review article discusses recent information concerning basic pentraxin 3 biology in inflammation and in innate immunity reactions as viewed by a cardiologist in the context of acute coronary events and by a surgeon in patients struck with multiple wounds who are at the same time menaced by bacterial infections.

The inflammatory response in cardiac surgery. An up-to-date overview with the emphasis on the role of heat shock proteins (HSPs) 60 and 70

Cardiac surgical operations are associated with the development of a systemic inflammatory response syndrome (SIRS). In most cases, the inflammatory response is apparent only in its subclinical form. In some cases, however, it can become clinically manifest or even life-threatening. This review article presents some new data regarding its biological importance, along with an insight into the recently discovered role played by heat shock proteins 60 and 70.

[Cardiac surgery operations and their influence on serum level of antiinflammatory cytokine interleukin-10]

BACKGROUND

Cardiac surgical operation is followed by the development of inflammatory reaction. This reaction is regulated in many ways including the production of antiinflammatory cytokines such as IL-10 to avoid potentially harmful effects of inflammation.

METHODS AND RESULTS

We compared serum levels of cytokines IL-10, IL-6, and IL-13 in the group of patients undergoing cardiac surgical operation using either cardiopulmonary bypass (CPB, n=17) or surged on the beating heart (n=17). We found significant elevation in the serum level of IL-10 during surgery with the peak immediately after finishing surgery in CPB patients and at the first postoperative day in non-CPB patients, respectively. There is statistically significantly higher level of IL-10 in CPB patients in comparison with non-CPB patients at the end of surgery. Serum level of IL-6 is elevated in both groups during surgery reaching maximum immediately after surgery in CPB patients and at the first postoperative day in patients without CPB, respectively. The serum levels of IL-13 are only nonsignificantly changed during operation and in postoperative period in both groups.

CONCLUSIONS

The intensity of inflammatory response in CPB patients which is enhanced by massive contact activation of blood and extensive ischemia-reperfusion injury is regulated by the production of antiiflammatory IL- 10 cytokine.

[Innate immunity, receptors for exogenous and endogenous danger patterns in immunopathogenesis of atherosclerosis--part 1: identification of danger signals by innate immunity]

Cellular and humoral components of innate immunity are able to identify danger signals both of the exogenous and endogenous origin. Exogenous danger signals are evolutionary conserved mosaics of danger patterns which are frequent in pathogenic microbes. Endogenous danger signals are raised during damage of self structures, by oxidative stress and/or by chemical modification of self molecules. Danger signals are identified by several families of molecules which are expressed on the surfaces of innate immunity cells. Among them the TLR receptors family which is associated with intracellular signaling pathway NF-kappaB is one of the most important. The inflammatory response is induced via activated NF-kappaB transcription factor.

[Innate immunity, receptors for exogenous and endogenous danger patterns in immunopathogenesis of atherosclerosis--part II: TLR receptors, significance of genetic polymorphism of danger signals receptors]

The most important set of receptors for danger patterns are TLR receptors. Together ten different TLR receptors were identified so far. Majority of TLR receptors is expressed on the cell surface to identify extracellulary localized danger signals. Some TLR receptors are also expressed in the intracellular compartment to identify intracellular danger signals. Receptors for danger signals display individual differences delineated by genetic polymorphism. The individual immune reactivity is developed in the context of genetic predisposition and the exposition to variable environmental factors. The differences in an individual immune reactivity are probably responsible for individual susceptibility or resistance to the development of immunopathological reactivity, which is involved in the immunopathogenesis of atherosclerosis.