A preliminary study of tracking B-cell kinetics in patients with lung transplantation by monitoring kappa-deleting recombination excision circles

Background: This study aims to evaluate humoral immune system response by measuring copy numbers of kappa-deleting recombination excision circles (KREC) gene segment from B lymphocytes in patients with lung transplantation. Methods: B etween S eptember 2015 a nd N ovember 2016, a total of 11 patients (8 males, 3 females; mean age: 45.4±12.0 years; range, 23 to 59 years) who underwent lung transplantation with different primary indications were included. The copy numbers of KREC gene segment were quantified using real-time polymerase chain reaction method in peripheral blood samples collected pre and post-transplantation. The samples of the patients were compared with the KREC levels in deoxyribonucleic acid extracted from blood samples of healthy children. Results: There was no significant change in KREC levels between pre and post-operation (p=0.594 and p=0.657), although the median values indicated that the highest increase in the KREC levels (7×10⁵- 12×10⁵; 85-170) was on Day 7 of transplantation. There was a positive correlation between the KREC levels (mL in blood) and lymphocytes at 24 h after transplantation (p=0.043) and between KREC copies per 10⁶ of blood and age on Day 7. Conclusion: Our preliminary results suggest that KREC l evels a s an indicator of B lymphocyte production are elevated after lung transplantation. A prognostic algorithm by tracking B cell kinetics after post-transplantation for long-term follow-up can be developed following the confirmation of these preliminary results with more patient samples.