Letter to the Editor
To the Editor:
Although the circulating leucocytes could be filtered during the ex vivo organ perfusion (EVOP), the main source of the inflammatory cytokines seems to be the resident leucocytes rather than the circulating cells; accordingly, there is no significant difference between the results of EVOP with or without leucocytic filtration.1 As the levels of the inflammatory cytokines determine the prognosis of the procedures of EVOP and the solid organ transplants,2 it is important to focus on the attenuation of their production.
Many studies documented the ratio between interleukin (IL) 6 and IL10 as a key player in the prognosis of the inflammatory conditions. A high IL6/IL10 ratio after transplantation is associated with primary lung graft dysfunction and 20-fold increased relative risk of mortality.3
Although the ratio between IL6 and IL10 serves as a reliable marker for the transplant prognosis, the levels of those cytokines are currently measured either during EVOP (representing the levels following donor’s death and the experience of the ischemic-reperfusion injury [IRI]) or following transplantation (the levels in the recipient’s blood), which does not save the precious time and costs, and risks the patient’s life.
As the main source of the graft cytokines is the resident leucocytes, a prior assessment of the mutations/polymorphisms associated with increased production/function of IL6 and or decreased production/function of IL10 (in addition to any other relevant genetic markers of inflammation, such as TNFα) in the leucocytes of the donor can provide valuable information about the suitability of the potential donor.
Accordingly, clinical studies should be conducted to evaluate the genetic profile of the genes of interest and their association with the success rates of the transplant procedures, as well as the frequencies of complications or graft failure following transplantation. This could be of great value in order to, at least, mark the future grafts as a “relatively high risk,” which would indicate the application of special immunomodulatory interventions, such as EVOP.
A strip assay for genotyping the IL6 and IL10 genes in the leucocytes of a blood sample could be performed by the decision-making for being a future organ donor, in order to assess whether the future grafts have the potential of an increased IL6/IL10 ratio in response to IRI and death.
The technique consists of the following steps:
- A blood sample is to be collected.
- Leukocytes are to be separated using a suitable protocol or technique.
- DNA from leukocytes is to be extracted.
- Polymerase chain reaction (PCR) and simultaneous labeling by fluorescent-labeled highly specific primers for all known IL6 and IL10 mutations and polymorphisms, provided that each mutation or polymorphism has a specific fluorescence color.
- Polymerase chain reaction products are then to be hybridized to the test strip.
- The test strip has the various known genotypic sequences of IL6 and IL10, which are highly complementary to the PCR products, fixed on it.
- The fixed genotypes on the test strip are colorless.
- When the fluorescent-labeled PCR products hybridize with the complementary genotypes, the others are washed out, so that, only the fixed colors can be seen and identified on the test strip under the fluorescent microscope.
Mohamed S. A. Mohamed
Faculty of General Medicine
University of Cologne
1. Luc JG, Aboelnazar NS, Himmat S, et alA leukocyte filter does not provide further benefit during ex vivo lung perfusion. ASAIO J 2017.5: 672–678,
2. Andreasson AS, Karamanou DM, Gillespie CS, et alProfiling inflammation and tissue injury markers in perfusate and bronchoalveolar lavage fluid during human ex vivo lung perfusion. Eur J Cardiothorac Surg 2017.51: 577–586,
3. Kaneda H, Waddell TK, de Perrot M, et alPre-implantation multiple cytokine mRNA expression analysis of donor lung grafts predicts survival after lung transplantation in humans. Am J Transplant 2006.6: 544–551,