Immune Function Assay (Immunknow) Drop Over First 6 Months After Renal Transplant: A Predictor of Opportunistic Viral Infections?

doi:10.1016/j.transproceed.2014.07.050

Transplantation Proceedings

Volume 46, Issue 7, September 2014, Pages 2220-2223

https://doi.org/10.1016/j.transproceed.2014.07.050 Get rights and content

Abstract

Background

The Immuknow assay (IKA; Cylex) is a T-cell immune function assay that evaluates immunoreactivity in immunocompromised patients. The aim of this study was to analyze IKA values in a cohort of kidney transplantation (KT) recipients to investigate correlations between single–time point low IKA values and their trend over time with cytomegalovirus (CMV) or BK virus (BKV) reactivation.

Methods

A total of 118 adult patients receiving deceased-donor KT were enrolled (55.6 ± 11.9 years old; 79 [66.9%] male). IKA CMV and BKV viremia determinations and were performed at months 1, 3, and 6 after surgery.

Results

Overall, 272 IKA determinations were performed: IKA values significantly decreased from month 1 (422 ± 184 ng/mL) to month 3 (330 ± 159 ng/mL; P < .001) and from month 3 to month 6 (300 ± 128 ng/mL; P = .030). IKA values did not correlate with renal function or viral reactivation at any time. However, patients with either CMV or BKV viremia had a trend to higher IKA values at month 1 and lower IKA values at month 6, even if the difference did not reach a statistical significance (P = .115).

Conclusions

Our study suggests that presence of low immunologic reactivity (IKA <225 ng/mL) is not associated with an increased risk of CMV and BKV reactivation over the 1st 6 months after KT. However, a trend to a more pronounced drop in IKA values over time was observed in patients with viral reactivation. These preliminary results suggests that drop in IKA values within the 1st post-KT months, unlike single–time point immune function assay, may predict the risk of opportunistic viral infections.

Section snippets

Study Population

Patients were eligible for inclusion if they received deceased-donor KT at our center from April 2010 to September 2012, for a total of 118 adult white patients (55.6 ± 11.9 years old; 79 [66.9%] male). All patients received induction therapy (basiliximab, 108/118 [91.5%]; recombinant antithymocyte globulin, 10/118 [8.5%]) and maintenance therapy with tacrolimus, mycophenolate, and steroid (109/118, 92.4%) or low-dose cyclosporine, everolimus, and steroids (8/118, 7.4%); 1 patient received only

Results

Overall, 272 IKA determinations (n = 76 at month 1; n = 95 at month 3; and n = 101 at month 6) were performed in 118 KT patients. IKA values significantly decreased from month 1 to month 3 (P < .001) and from month 3 to month 6 (P = .030). The percentage of patients with IKA values <225 ng/mL was 15.8% (12/76) at month 1, 27.4% (26/95) at month 3, and 25.7% (26/101) at month 6 (P = .167, for trend; P = .061, comparing month 1 vs months 3 and 6). Mean serum creatinine levels were 1.70 ±

Discussion

This preliminary analysis shows that a trend of decreasing IKA values over time appears to be more pronounced in patients with CMV or BKV reactivation, although the difference is not statistically significant (P = .1). In contrast, absolute spot IKA values are not associated with either viral reactivation or renal function level in this cohort. This observation, if confirmed in larger prospective studies, can contribute to shedding light on the correct use and interpretation of IKA testing and

References (16)

N.M. Heikal et al.
Immune function surveillance: association with rejection, infection and cardiac allograft vasculopathy
Transplant Proc
(2013)
H.H. Moon et al.
Can immune function assay predict infection or recovery?
Transplant Proc
(2012)
de Paolis et al.
“Immuknow” to measurement of cell mediated immunity in renal transplant recipients undergoing short-term evaluation
Transplant Proc
(2011)
D.R. Post et al.
Assessing relative risks of infection and rejection: a meta-analysis using an immune function assay
Transplantation
(2006)
A. Zeevi et al.
Cylex Immuknow cell function assay
Methods Mol Biol
(2013)
J.A. Fishman
Infection in solid organ transplant recipients
N Engl J Med
(2007)
A. Gautman et al.
Cell mediated immunity and post transplant viral infections—role of a functional immune assay to titrate immunesuppression
Int Immunopharmacol
(2006)
H.S. Te et al.
Use of immune function test in monitoring immunosuppression in liver transplant recipients
Clin Transplant
(2012)

There are more references available in the full text version of this article.

Cited by (11)

Lymphocyte function based on IFN-γ secretion assay may be a promising indicator for assessing different immune status in renal transplant recipients
2021, Clinica Chimica Acta
Citation Excerpt :
Obviously, although some studies have suggested that cytokines in immune cells can reflect the function of lymphocytes and the overall immune network systematically [38], it is not completely true to say that cytokines detection lacking complete investigation is the best tool in assessing the immune system network of recipients [39]. IFN-γ participates in activation, proliferation, and effect of T cells and promotes graft vascular disease as a pro-inflammatory cytokine usually [21,38,40]. Since IFN-γ is secreted by a variety of lymphocytes, our previous study created a convenient method to simultaneously detect IFN-γ secretion by CD4+, CD8+ T cells, and NK cells by stimulating whole blood with PMA+/ionomycin for 4 h.
Immunological monitoring plays a crucial role in organ recipients for allowing tailoring of immunosuppression. However, there is still a paucity of promising indicators for detecting immune status in recipients.
We conducted a prospective study to characterize the immune status by detecting dynamically lymphocyte subsets and function (represented by the abilities to secrete IFN-γ) in the first 6 months posttransplant in renal recipients. Participants were classified into an immune stable group, infected group, and rejected group.
In the stable group, our study suggested that the counts and function of CD4+ T, CD8+ T, and NK lymphocytes decreased to their nadir at week 2, and thereafter these indicators were gradually restored. The counts exceeded pre-operative levels, whereas function did not reach the pre-transplant levels by 6 months. We demonstrated that function of lymphocytes was considerably decreased in infected recipients compared with the stable group when infection occurred. By contrast, the function of lymphocytes was obviously increased at the point of rejection. Receiver operating characteristic (ROC) analysis in the combination of subsets and function of lymphocytes presented a superior clinical value with an area under the curve (AUC) of 0.903 in the diagnosis of infected receivers, and IFN-γ+CD8+ T cells% is the highest indicator with the auROC curve of 0.862. Another ROC analysis confirmed that IFN-γ+CD4 T cells% presented a preferable diagnostic value with an area of 0.887 for rejected recipients.
In conclusion, the ability of lymphocyte subsets secreting IFN-γ may provide a promising assessment of immune status in recipients and allow timely modifying immunosuppression.
Monitoring cellular immune function of renal transplant recipients based on adenosine triphosphate (ATP) production by mitogen-induced CD4+ T helper cells
2018, Biomedicine and Pharmacotherapy
Citation Excerpt :
Interestingly, similar differences were observed in iATP values between SGF patients and those who developed ARE or infection during the one-month follow-up after the test. These observations are in line with previous reports [15,16,20]. Sanchez-Velasco et al. for instance, showed that the iATP concentration of CD4+ T cells in RTRs with infection was significantly less than those without infection [16].
Maintaining the balance between over- and under-immunosuppression has a critical role for successful immunosuppressive therapy after renal transplantation. We studied the predictive value of our functional immune assay, which works based on adenosine triphosphate (ATP) levels, in determining risk of infection and rejection among renal transplant recipients (RTRs). A total of 65 RTRs with less than 1 month (RTRL1) and 48 RTRs with more than 6 months (RTRM6) of post-transplant time, and 56 healthy individuals were included. Upon lymphocyte activation by phytohemagglutinin (PHA), CD4+ T cells were separated using magnetic beads (Dynabeads), the intracellular ATP (iATP) concentrations were measured by luciferin-luciferase reaction, and compared within and between the groups. Activated CD4+ cells iATP production directly correlated with post-transplant time (r = 0.32, P = 0.011). The iATP levels were significantly lower in both RTRL1 and RTRM6 groups compared to control (P < 0.001), and in the RTRL1 group compared to the RTRM6 (P < 0.05). The iATP concentrations were significantly lower in patients who suffered from infection versus the RTRs with stable graft function (SGF). However, the iATP levels were higher in those with allograft rejection episode (ARE). Our optimization experiments showed that best iATP levels cutoffs were 472.5 and 572.5 ng/ml for predicting risk of ARE, and 218.5 and 300.5 ng/ml for predicting risk of developing infection in RTRL1 and RTRM6 patients, respectively. iATP levels measured by immune function assay might be a promising predictive tool for identifying RTRs who are at risk of developing infection or allograft rejection.
An optimized protocol for adenosine triphosphate quantification in T lymphocytes of lymphopenic patients
2016, Journal of Immunological Methods
Citation Excerpt :
Lower ATP values have been associated with infections, when higher ATP concentrations correlated with a higher risk of graft rejection (Kowalski et al., 2006). Repeated measurements of ATP production by CD4 + lymphocytes, rather than absolute values, have been proposed to predict adverse events (Quaglia et al., 2014). However, whether the low ATP responses measured during infectious episodes reflect inadequate over-dosage of immunosuppressive drugs or sepsis-induced immunosuppression remains unclear (Bhorade et al., 2008).
In several clinical contexts, the measurement of ATP concentration in T lymphocytes has been proposed as a biomarker of immune status, predictive of secondary infections. However, the use of such biomarker in lymphopenic patients requires some adaptations in the ATP dosage protocol. We used blood from healthy volunteers to determine the optimal experimental settings. We investigated technical aspects such as the type of anticoagulant for blood sampling, the effect of freeze and thaw cycles, the reagent and sample mixing sequence, and the optimal dilution buffer. We also shortened the incubation time to 8 h, and even showed that a 30 min incubation may be sufficient. To evaluate the ATP rise upon lymphocyte activation, the optimal dose of stimulant was defined to be 4 μg/mL of phytohaemagglutinin. Lastly, we determined that the number of T cells needed for this measurement was as low as 50,000, which is compatible with the existing lymphopenia in clinical settings. This optimized protocol appears ready to be assessed in lymphopenic patients to further investigate the interconnection between T lymphocyte metabolism and impaired phenotype and functions.
Approaches for monitoring of non virus-specific and virus-specific T-cell response in solid organ transplantation and their clinical applications
2015, Journal of Clinical Virology
Citation Excerpt :
Of note, a large-scale single-center study in KTR failed to show an association between single time point ImmuKnow measurements and the episodes of OI in the subsequent 90 days [18]. In other studies, the trend of the ImmuKnow values over time during the first year post-transplant was suggested to more reliably reflect the risk of BKV infection [19] or HCMV and BKV infections [20]. Overall, ImmuKnow results should be interpreted with caution keeping in mind that the assay provides a nonspecific estimate of T-cell function.
Opportunistic viral infections are still a major complication following solid organ transplantation. Immune monitoring may allow the identification of patients at risk of infection and, eventually, the modulation of immunosuppressive strategies. Immune monitoring can be performed using virus-specific and non virus-specific assays. This article describes and summarizes the pros and cons of the different technical approaches. Among the assays based on non virus-specific antigens, the enumeration of T-cell subsets, the quantification of cytokines and chemokines and the quantification of intracellular adenosine triphosphate following mitogen stimulation are described and their clinical applications to determine the risk for viral infection are discussed. In addition, current specific methods available for monitoring viral-specific T-cell responses are summarized, such as peptide-MHC multimer staining, intracellular cytokine staining, enzyme-linked immunospot and virus-specific IFN-γ ELISA assays, and their clinical applications to determine the individual risk for opportunistic viral infections with human cytomegalovirus, Epstein-Barr virus and polyoma BK virus are discussed. The standardization of the procedure, the choice of the antigen(s) and the criteria to define cut-off values for positive responses are needed for some of these approaches before their implementation in the clinic. Nevertheless, immune monitoring combined with virological monitoring in transplant recipients is increasingly regarded as a helpful tool to identify patients at risk of infection as well as to assess treatment efficacy.
Serological response in lung transplant recipients after two doses of sars-cov-2 mrna vaccines
2021, Vaccines
BK virus and pathophysiology of associated diseases
2019, Virologie

View all citing articles on Scopus

View full text

37th Congress of the Italian Transplantation SocietyRenal transplantationImmune Function Assay (Immunknow) Drop Over First 6 Months After Renal Transplant: A Predictor of Opportunistic Viral Infections?

Abstract

Background

Methods

Results

Conclusions

Section snippets

Study Population

Results

Discussion

Transplant Proc

Transplant Proc

Transplant Proc

Assessing relative risks of infection and rejection: a meta-analysis using an immune function assay

Transplantation

Cylex Immuknow cell function assay

Methods Mol Biol

Infection in solid organ transplant recipients

N Engl J Med

Cell mediated immunity and post transplant viral infections—role of a functional immune assay to titrate immunesuppression

Int Immunopharmacol

Use of immune function test in monitoring immunosuppression in liver transplant recipients

Clin Transplant

37th Congress of the Italian Transplantation Society
Renal transplantation
Immune Function Assay (Immunknow) Drop Over First 6 Months After Renal Transplant: A Predictor of Opportunistic Viral Infections?