Lung Transplant Patients Show a Dissimilar Peripheral B-Cell Subset Ratio Compared With Healthy Controls.

OBJECTIVES: Lung transplant is a last treatment option for patients with end-stage pulmonary disease. Chronic lung allograft dysfunction, which generally manifests as bronchiolitis obliterans syndrome, is a major long-term survival limitation. Bronchiolitis obliterans syndrome is diagnosed when forced expiratory volume in 1 second declines > 20% in the absence of known causes. B cells can either contribute or restrain the development of bronchiolitis obliterans syndrome (eg, via induction of alloimmune antibodies, regulation of cellular immunity, and induction of tolerance). Here, we explored how peripheral B-cell subsets were altered in lung transplant recipients with bronchiolitis obliterans syndrome. MATERIALS AND METHODS: Fresh whole blood samples were analyzed from 42 lung transplant recipients, including 17 with bronchiolitis obliterans syndrome; samples from these groups were compared with 10 age-matched healthy control samples. B-cell subsets were analyzed using flow cytometry, and relative distributions of subsets were compared. Changes in forced expiratory volume in 1 second were also determined. RESULTS: Absolute B-cell count was significantly increased in transplant recipients with bronchiolitis obliterans syndrome. Transitional (CD24+CD38+) and naïve (CD27-IgD+) B cells were decreased in lung transplant patients, with transitional B cells almost absent in those with bronchiolitis obliterans syndrome. Double-negative (CD27-IgD-) memory B cells were significantly increased (P < .001). No differences were found for plasmablasts (CD38+CD24-) and switched (CD27+IgD-) and non-switched (CD27+IgD+) memory B cells. Correlation analyses showed positive correlations between lung function and naïve B cells in transplant recipients (P = .0245; r = -0.458). CONCLUSIONS: Peripheral B-cell count and subset distribution were altered in lung transplant recipients with and without bronchiolitis obliterans syndrome compared with healthy controls. Transitional and naïve B-cell decreases may be caused by differentiation toward double-negative B-cells, which were increased. The correlation between forced expiratory volume and naïve B cells during follow-up care may be clinically interesting to investigate.

Lung Transplantation Has a Strong Impact on the Distribution and Phenotype of Monocyte Subsets.

BACKGROUND: Lung transplantation (LTx) is a last treatment option for patients with an end-stage pulmonary disease. Chronic lung allograft dysfunction, which generally manifests as bronchiolitis obliterans syndrome (BOS), is a major long-term survival limitation. During injury, inflammation and BOS monocytes are recruited. We determined whether changes in count, subset distribution, and functionality by surface marker expression coincided with BOS development. METHODS: Fresh whole-blood samples were analyzed from 44 LTx patients, including 17 patients diagnosed with BOS, and compared with 10 age-matched healthy controls and 9 sarcoidosis patients as positive controls. Monocytes were quantified and analyzed using flow cytometry. Based on surface marker expression, classical, intermediate, and nonclassical subsets were determined, and functional phenotypes were investigated. RESULTS: The absolute count of monocytes was decreased in LTx and slightly increased in BOS patients. The relative count shifted toward classical monocytes at the expense of nonclassical monocytes in LTx and BOS. Surface marker expression was highest on intermediate monocytes. The expression of both CD36 and CD163 was significantly increased in the LTx and BOS cohort. The difference between the BOS cohort and the LTx cohort was only subtle, with a significant decrease in HLA-DR expression on nonclassical monocytes in BOS. CONCLUSIONS: Monocyte subsets and surface marker expression changed significantly in transplantation patients, while BOS-specific changes were understated. More research is needed to determine whether and how monocytes influence the disease process and how current immunosuppressants affect their normal function in vivo.

Effect of meal temperature on the frequency of gastric myoelectrical activity.

It was hypothesized that the transient post-prandial decrease of the dominant frequency in the electrogastrogram (EGG) is related to the temperature of the meal. In a randomized three-period cross-over design. EGG recordings were made in 10 healthy volunteers. A liquid meal (36 kcal, 300 mL) was ingested at either 4, 37 or 55 degrees C. The changes in the dominant EGG frequency that occurred in the first 25 min postprandial were calculated using running spectrum analysis. After the meal a transient shift in frequency was seen, which was significantly greater after the cold meal than after the other meals (P < 0.001), with a greater decrease in the dominant frequency (4 degrees C: -0.75 [-0.92(-)-0.68], 37 degrees C: -0.34 [-0.51(-)-0.18], 55 degrees C: -0.30 [-0.45(-)-0.12] cpm; P = 0.020) and a longer duration (4 degrees C: 16 [13-19], 37 degrees C: 12 [6-14], 55 degrees C: 5 [3-8] min; P = 0.014). No differences were found between the 37 degrees C and 55 degrees C meals, the power ratios or the number of dysrhythmias. The magnitude of the postprandial shift in frequency of gastric myoelectrical activity depends on the temperature of the meal. Meal temperature should be taken into account in studies on postprandial gastric motility.