Assessment of the Th1/Th2 paradigm in whole blood in atopy and asthma. Increased IFN-gamma-producing CD8(+) T cells in asthma.

Atopy is characterized by an immune system that is biased to T helper cell, type 2 (Th2) activation. This condition predisposes to asthma, a disease in which a Th2 activation was found in blood and lungs. However, most blood studies have considered purified cells, which might give an incomplete view of immune reactions. In this study, we assessed in whole blood cultures the Th1/Th2 paradigm in atopy and asthma. Sixty-nine subjects (31 atopic asthmatics, six nonatopic asthmatics, 13 atopic nonasthmatics, and 19 control subjects) were included in this study. Interleukin-4 (IL-4), interferon gamma (IFN-gamma), and IL-12 were assayed in stimulated whole blood culture supernatants by using a flow cytometer microsphere-based assay. Intracellular IL-4 and IFN-gamma were detected in T cells and CD8(+) T cells by flow cytometry. Atopy was characterized by a higher production of IL-4, which was correlated to total IgE levels, and by an impairment of the T-cell capacity to produce IFN-gamma. This impairment was correlated to the number of positive skin tests. In asthma, the overproduction of IL-4 was still found if atopy was present. Unexpectedly, an overproduction of IFN-gamma was found, which was related to an increased capacity of CD8(+) T cells to produce IFN-gamma. The number of IFN-gamma-producing CD8(+) T cells was related to asthma severity, to bronchial hyperresponsiveness, and to blood eosinophilia. In addition, this number was correlated to IL-12 production. These results show that in addition to the well-known Th2 inflammation in asthma, there are IFN-gamma-producing CD8(+) T cells in the blood, possibly controlled by IL-12.

Comparative use of cold blood potassium cardioplegia in coronary bypass patients necessitating long (2.5-6 h) versus short (less than 1.5 h) aortic cross-clamp times.

In symptomatic patients with severe diffuse multivessel coronary disease undergoing bypass surgery, complete revascularization with multiple bypass grafts using saphenous vein and internal mammary conduits, and multiple endarterectomies may be necessary. Such complex surgeries may require long aortic cross-clamp times in excess of 2.5 h. To evaluate the myocardial preservation provided by cold potassium blood cardioplegia, two groups of consecutive patients using nearly similar surgical techniques were compared. Group A consisted of 100 patients who received an average of 3.8 grafts per patient and had a mean aortic cross-clamp time of 66 (range 15-90) min. Group B was comprised of 100 patients who received an average of 9.3 grafts per patient and had a mean cross-clamp time of 187 (range 150-351) min. Operative mortality and perioperative myocardial infarction were low (0-2%) and were not significantly different between the groups. In addition, the postoperative creatine kinase-MB isoenzyme levels, use of pharmacologic and/or mechanical (i.e., intra-aortic balloon) support, and follow-up exercise treadmill tests were not significantly different in the two groups. These findings suggest that cold potassium blood cardioplegia is equally protective of the myocardium during surgical revascularization in patients with short aortic cross-clamp times (less than 1.5 h) as in those with severe diffuse multivessel coronary artery disease requiring long cross-clamp times exceeding 2.5 h and up to 6 h.