Screening of mortality in transplant patients using an assay for immune function

Abstract

Background So far, the ImmuKnow Immune Cell Function Assay (Cylex, Inc., Columbia, MD, USA) has been used to assess risks of infection and rejection in transplant patients. We hypothesized that the ImmuKnow assay might be used for mortality screening in transplant patients overall. Methods In the period of February 2007 to December 2009, at the Uppsala University Hospital, 362 patients who received either kidney, kidney + pancreas, kidney + islet cells, liver or liver + kidney allografts were randomly screened using the ImmuKnow assay. All causes of mortality were compared between two groups: patients with at least one ImmuKnow assay below 175 ng/mL and patients with all ImmuKnow assays from 175 ng/mL and above. Subsequently, the frequency of rejection within thirty days of the ImmuKnow assay was compared between these two groups. Results The study included 1031 ImmuKnow assays obtained from the 362 patients. A total of 111 patients had at least one ImmuKnow below 175 ng/mL and 251 patients had all their ImmuKnow assays from 175 ng/mL and above. By January 31st 2010, 16 of 111 patients (14.4%) with at least one ImmuKnow assay below 175 ng/mL were deceased, compared to 13 of 251 patients (5.2%) with all ImmuKnow assays from 175 ng/mL and above ( p = 0.0053, Fisher's exact test). There was no difference in the frequency of rejection between the two groups (19.8% versus 17.5%, p = 0.66). Conclusions In addition to assessing relative risks of infection and rejection in transplant patients, the ImmuKnow assay may be used to identify patients with increased risk of short-term mortality. Transplant patients being highly overimmunosuppressed as assessed by the ImmuKnow assay do not seem to have a lower risk of short-term rejection.