Chemokine redundancy in BOS pathogenesis. A possible role also for the CC chemokines: MIP3-beta, MIP3-alpha, MDC and their specific receptors.

Bronchiolitis obliterans syndrome (BOS) is one of the most important factors limiting the long-term survival of lung transplant recipients (LTR), however its pathogenesis still remains unclear. We hypothesized that an increased production of certain specific proinflammatory mediators in the first post-transplant year would predispose to BOS. We retrospectively evaluated temporal kinetics of some CC chemokines that have not yet been evaluated, including CCL3/MIP1-alpha, CCL4/MIP1-beta, CCL17/TARC, CCL19/MIP3-beta, CCL20/MIP3-alpha, CCL22/MDC and CCL26/eotaxin, in broncho-alveolar lavage fluid (BAL-f) in the first post-transplant year in a cohort of 8 LTR before the development of BOS (pre-BOS LTR) and 8 LTR with long-term stable clinical conditions (stable LTR). Chemokine levels were assayed by means of a multiplex sandwich ELISA. Furthermore, for those ligands which resulted significantly predictive of BOS onset, we analyzed the expression of specific receptors (CCR) on BAL cells. The proportion of CCR-expressing BAL cells was assessed by flow cytometry. We demonstrated that MIP3-beta/CCL19, MIP3-alpha/CCL20, MDC/CCL22 levels at 6 months post-transplant significantly predicted BOS onset. In addition, the temporal behavior of these factors resulted significantly different in pre-BOS patients as compared to stable LTR. Finally the expression of CCR was documented on BAL lymphocytes and macrophages, and, in some cases, their expression was found to vary between the two groups. Within the complexity of the chemokine network, these three CCL factors could play an additive role in the pathogenesis of the inflammatory process leading to bronchiolar fibro-obliteration.

Peripheral CD4(+)CD25(+) TREG cell counts and the response to extracorporeal photopheresis in lung transplant recipients.

Extracorporeal photopheresis (ECP) has been proposed as a possible alternative therapy for patients with bronchiolitis obliterans syndrome (BOS), with some evidence of efficacy. Although the mechanism by which ECP exerts its protective effects remains to be determined, two recent studies suggest that the modulation of transplant immune rejection may depend on the capacity to increase the number of peripheral T-regulatory (Treg) cells. We evaluated the effect of ECP treatment on the number of naturally occurring CD4(+)CD25(+) Treg cells in the peripheral blood of six lung transplant recipients: in five cases after failure of augmented or changed immunosuppression for BOS, and in one case owing to persistent acute rejection in a patient who contracted chronic hepatitis C viral infection after lung transplant. A functional stabilization was observed in three of our five patients with BOS, which was accompanied by a slight increase or stabilization of the number of peripheral blood CD4(+)CD25(high) cells with in vitro features of Treg cells. On the contrary, two patients with BOS who did not experience graft functional stabilization also showed a decline in the peripheral Treg subset. In the last patient Treg cell kinetics showed stabilization during the first 5 months of ECP treatment when lung function remained stable and graft histology normalized but showed a subsequent decrease, predating BOS diagnosis. In all, our results indicate that ECP may modulate peripheral Treg cell number but the time course of peripheral Treg cells varies according to graft function.

Histochemical study of cardiac mast cells degranulation and collagen deposition: interaction with the cathecolaminergic system in the rat.

Although their role in the cardiovascular system is still largely unknown, mast cells are present in the myocardium of both experimental animals and humans. Interestingly, cathecolaminergic nerve fibres and mast cells are often described in close morphological and functional interactions in various organs. In the present study we investigated the effects of chronic interference with beta-adrenergic receptors (via either sympathectomy or beta-blockade) on cardiac mast cell morphology/activation and on interstitial collagen deposition. In rats subjected to chemical sympathectomizy with the neurotoxin 6-hydroxydopamine (6-OHDA) we observed a significant increase of mast cell density, and in particular of degranulating mast cells, suggesting a close relationship between the cardiac catecholaminergic system and mast cell activation. In parallel, chronic 6-OHDA treatment was associated with increased collagen deposition. The influence of the beta-adrenergic receptor component was investigated in rats subjected to chronic propranolol administration, that caused a further significant increase in mast cell activation associated with a lower extent of collagen deposition when compared to chemical sympathectomy. These data are the first demonstration of a close relationship between rat cardiac mast cell activation and the catecholaminergic system, with a complex interplay with cardiac collagen deposition. Specifically, abrogation of the cardiac sympathetic efferent drive by chemical sympathectomy causes mast cell activation and interstitial fibrosis, possibly due to the local effects of the neurotoxin 6-hydroxydopamine. In contrast, beta-adrenergic blockade is associated with enhanced mast cell degranulation and a lower extent of collagen deposition in the normal myocardium. In conclusion, cardiac mast cell activation is influenced by beta-adrenergic influences.

The frequency of interleukin-10- and interleukin-5-secreting CD4+ T cells correlates to tolerance of transplanted lung.

Posttransplant bronchiolitis obliterans syndrome (BOS) results from a chronic immunological/inflammatory insult that leads to fibro-obliteration of the lumen of the allograft airways. The functional T-cell response that is associated with graft acceptance needs to be further clarified in humans. The aim of the present study was to assess the functional activity of peripheral CD4+ T lymphocytes in nine lung transplant recipients with BOS stage II or III (mean 5.4 years after transplant), in seven lung patients with stable clinical conditions (3.4 years posttransplant); and in six normal controls. Peripheral CD4+ T cells, obtained by magnetic bead vs negative purification, were studied using a computer-assisted enzyme-linked immunospot assay (ELISPOT) to assess the number of IFN-gamma-, interleukin (IL)5-, and IL10-gamma-producing cells (no./10(6) CD4+ cells) after allogeneic stimulation. The frequencies of IFN-gamma-producing CD4+ cells did not change significantly in stable patients compared to those with BOS. Interestingly in BOS, the number of IL5- and IL10-producing cells was significantly lower than in stable patients (P < or = .05), suggesting a possible role of these Th2 cytokines in the modulation of graft tolerance.