Increased Frequency of BK Virus-Specific Polyfunctional CD8+ T Cells Predict Successful Control of BK Viremia After Kidney Transplantation

BACKGROUND

BK virus infection remains an important cause of loss of allograft function after kidney transplantation. We sought to determine whether polyfunctional T cells secreting multiple cytokines simultaneously, which have been shown to be associated with viral control, could be detected early after start of BK viremia, which would provide insight into the mechanism of successful antiviral control.

METHODS

Peripheral blood mononuclear cells collected during episodes of BK viral replication were evaluated by multiparameter flow cytometry after stimulation by overlapping peptide pools of BK virus antigen to determine frequency of CD8+ and CD4+ T cells expressing 1 or more cytokines simultaneously, as well as markers of T-cell activation, exhaustion, and maturation.

RESULTS

BK virus controllers, defined as those with episodes of BK viremia of 3 months or less, had an 11-fold increase in frequency of CD8+ polyfunctional T cells expressing multiple cytokines, as compared with patients with prolonged episodes of BK viremia. Patients with only low level BK viremia expressed low frequencies of polyfunctional T cells. Polyfunctional T cells were predominantly of the effector memory maturation subtype and expressed the cytotoxicity marker CD107a.

CONCLUSIONS

Noninvasive techniques for immune assessment of peripheral blood can provide insight into the mechanism of control of BK virus replication and may allow for future patient risk stratification and customization of immune suppression at the onset of BK viremia.

Co-infections of malaria and soil-transmitted helminths in localities with different levels of urbanisation in the Mount Cameroon region

Malaria co-exists with intestinal helminths and they have different effects on infected individuals. A total of 235 and 208 children from Ekona and Great Soppo respectively of both sexes aged 4–14 years were enrolled into a cross-sectional study.Capillary blood was collected for detection and determination of malaria parasitaemia as well as PCV. Stool samples were collected for quantitative determination of helminth ova by Kato-Katz technique.The prevalence of malaria and helminths was higher in Ekona than Great Soppo. In Great Soppo, Trichuris was the most prevalent helminth than Great Soppo and an association was found between these co-infections. More children were co-infected in Ekona and co-infecting species were Ascaris and Plasmodium falciparum.The prevalence of malaria and intestinal helminths as well as co-infection was lower in Great Soppo than in Ekona, probably due to increased urbanization in Great Soppo than Ekona.

Predictors of between-method differences in cardiac output measurement using thoracic electrical bioimpedance and thermodilution

OBJECTIVES

To evaluate the usefulness of transthoracic electrical bioimpedance in trending changes in cardiac output after cardiac surgery, and to identify predictors of differences between cardiac output measured by thermodilution and transthoracic electrical bioimpedance methods.

DESIGN

Prospective repeated-measures study.

SETTING

University-affiliated tertiary care center.

PATIENTS

Thirty-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement.

INTERVENTIONS

Simultaneous paired cardiac output measurements by transthoracic electrical bioimpedance and thermodilution were made at four time points: within 2 hrs of intensive care unit (ICU) admission; when the patient reached a normothermic temperature; after extubation; and 24 hrs after ICU admission.

MEASUREMENTS AND MAIN RESULTS

Mean measurements by each method over time did not differ, except at ICU admission, when compared by repeated-measures analysis of variance. For each time point, bias and precision between methods were calculated. Bias calculations ranged from 0.02 to 0.21 L/min/m2. Precision calculations ranged from 1.06 to 1.52 L/min/m2. Predictors of between-method differences identified by a multiple regression model of hemodynamic variables were: increased systemic vascular resistance index, decreased mean arterial pressure (MAP), and the presence of atrial or ventricular pacing.

CONCLUSIONS

While mean postoperative cardiac output measurements did not differ by method over time, agreement between transthoracic electrical bioimpedance and thermodilution methods was poor in the immediate postoperative period, with precision calculations indicative of clinically significant differences. Increased systemic vascular resistance index and decreased MAP were predictive of larger between-method differences.