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Biomedical subjects

I Paradis

Publications and source records attributed to I Paradis.

26 records · Page 2Linked to original sources
PubMed1992

Proliferation of cytomegalovirus-primed lymphocytes in bronchoalveolar lavages from lung transplant patients.

Previous reports have described an association between cytomegalovirus infection and increased donor-specific alloreactivity of bronchoalveolar lavage (BAL) lymphocytes in transplanted lungs and a higher risk of bronchiolitis obliterans due to chronic rejection. We have postulated that during infection, intragraft CMV-specific lymphocytes are activated and release lymphokines that augment cellular rejection. This study deals with an analysis of CMV antigen induced proliferation of 28 BAL lymphocyte and 27 peripheral blood lymphocytes samples from 17 lung transplant patients with or without CMV infection. Kinetic studies of lymphocyte proliferation have shown that CMV infection of the lung allograft is associated with an accelerated response of BAL lymphocytes but not PBL, following in vitro exposure to CMV antigen. These findings indicate an accumulation of primed CMV-specific lymphocytes within the lung allograft during CMV infection. Evidence has also been obtained that primed CMV-specific lymphocytes may persist for months in BAL. We conclude that the CMV antigen induced proliferation assay is useful for studies of CMV infection in transplant patients.

Antigens, Viral↗
PubMed1990

Life in the allogeneic environment after lung transplantation.

Because infection and rejection are the principal complications of any transplant procedure and because the alveolar macrophage is crucial to the defense of the lung from infection and may play a role in lung allograft rejection, we have begun to assess functions of this cell that are thought to be important in lung defense from infection and in transplant immunity. Antimicrobial functions include chemotaxis, which is a mechanism for recruiting macrophages to sites of inflammation and phagocytosis, and intracellular killing of microorganisms. As an accessory cell, the alveolar macrophage is necessary for an effective immune response to develop against either microorganisms or transplantation antigens. Our results indicate that the chemotactic, phagocytic but not the killing capability of alveolar macrophages from lung recipients is impaired. Alveolar macrophages and blood monocytes from lung recipients are also significantly impaired in their support for mitogen and antigen presentation to lymphocytes. Thus, the generation of an effective immune response to a microorganism may be impaired. Alveolar macrophages from lung recipients, however, function as well as those from normal subjects in stimulating lymphocyte proliferation in response to donor antigens (primed lymphocyte test) or unrelated allogeneic antigens (mixed lymphocyte reaction), while their respective blood monocytes function poorly in this regard. Our conclusions are that the antimicrobial functions of the alveolar macrophages are impaired after lung transplantation and this may be one mechanism to explain the unusual susceptibility of the lung allograft to infection. Those functions related to transplant immunity, however, are preserved and indicate that the alveolar macrophage may play a role in allograft rejection.

Adolescent↗
PubMed1990

HLA-class II antigen expression in human heart-lung allografts.

Long-term survival in heart-lung transplantation has ben hindered by the development of bronchiolitis obliterans (OB), which is believed to be a manifestation of chronic rejection of the lung. Since HLA-class II antigens are involved in the rejection response, the distribution of the class II products HLA-DR, HLA-DQ, and HLA-DP were studied in normal lung, and in transplanted lung with and without OB, utilizing frozen-section immunohistochemical techniques. All three allelic products are usually expressed on the epithelial, endothelial, and mesenchymal components of the lung. Sequential transbronchial biopsies from 4 recipients before and concurrent with the diagnosis of OB were stained with serial dilutions of monoclonal antibodies to assess the level of expression of the above class II products. Increased levels of HLA-DR and HLA-DP antigens may be seen on the bronchial and bronchiolar epithelium during OB, but the changes are subtle and complicated by many other variables. Additional studies are needed to confirm these preliminary results.

Bronchiolitis Obliterans↗
PubMedDate not supplied

Monitoring of acute lung rejection and infection by bronchoalveolar lavage and plasma levels of hyaluronic acid in clinical lung transplantation.

Local immunological injury caused by acute lung rejection leads to fibroblast proliferation. Hyaluronate is a product of activated fibroblasts and possibly an indicator of fibroblast proliferation. One hundred thirty-six bronchoalveolar lavage and plasma hyaluronate assays were performed in 57 lung transplant recipients. Pulmonary endothelial cell function was assessed by measuring bronchoalveolar lavage levels of purine nucleoside phosphorylase. Presence of acute cellular rejection was monitored by transbronchial biopsy histologic evaluation and was classified as minimal to mild (acute rejection I, II) and moderate to severe (acute rejection III, IV). Infection was confirmed by bronchoalveolar lavage culture and antibiotic sensitivity. Bronchoalveolar lavage hyaluronate levels in clinically stable recipients were 33.5 +/- 4.69 micrograms/L and were significantly higher than with clinically stable recipients (p = 0.0001), infection (p = 0.008), or mild rejection (p = 0.001). Levels were highest in recipients with diffuse alveolar damage (392.4 +/- 60.6 micrograms/L). Diffuse alveolar damage also resulted in significant elevations of plasma HA as compared with stable recipients (p = 0.001) and mild rejection. We conclude that clinically significant injury to the allograft from rejection or diffuse alveolar damage can be assessed by bronchoalveolar lavage hyaluronate assays and suggest that the source of hyaluronate in these instances are activated fibroblasts.

Acute Disease↗
PubMedDate not supplied

A working formulation for the standardization of nomenclature and for clinical staging of chronic dysfunction in lung allografts. International Society for Heart and Lung Transplantation.

A clinically applicable, standardized method for assessing functional results after lung transplantation is required to evaluate factors that may affect long-term outcome, to permit comparison of results from different centers, and to evaluate results of clinical trials. An ad hoc working group was established under the auspices of the International Society for Heart and Lung Transplantation for the purpose of developing such a clinically applicable system. Chronic allograft dysfunction is often associated with pathologic findings of obliterative bronchiolitis, the cause of which has not been defined. Physiologically, such dysfunction is associated with obstructive airways disease. The group concluded that the forced expiratory volume in 1 second was the most reliable and consistent indicator of graft dysfunction, excluding other identifiable causes. The term bronchiolitis obliterans syndrome was adopted to describe such dysfunction, recognizing that there may or may not be pathologic evidence of bronchiolitis obliterans present. Four stages of bronchiolitis obliterans syndrome were defined, each with two subcategories to indicate whether pathologic evidence of obliterative bronchiolitis had been identified. This working formulation will require reappraisal in the future to reassess its practical application and to make such adjustments as may seem appropriate.

Bronchiolitis Obliterans↗