Assessment of extracorporeal photopheresis related cell damage

Extracorporeal photochemotherapy (ECP) is emphasized chiefly as it has a high safety profile. However, the genotoxic effects of ECP are not known. This experimental study aimed to assess the potential genotoxic impact of ECP treatment by the AKLIDES system, a new generation standardized and automated evaluation method.

Buffy coats were obtained from the blood of 26 healthy volunteers, and ECP was applied to 2 j/cm2 UV-A for two hours. After the DNA isolation procedure, all slides were stained with DAPI to visualize lymphocytes, FITC for visualization of damage foci marker (γH2AX), and APC for visualization of repair foci marker (53BP1). With the AKLIDES imaging system, all parameters were evaluated.

Median damage marker Foci γ-H2AX before and after ECP were 11.42 and 18.65 arbitrary units, respectively (p = 0.153). Median repair marker foci 53BP1 (repair biomarker) before and after ECP were measured as 4.17 and 6.7 arbitrary units. The difference was also not statistically significant (p = 0.088). Although 58 % of cells were affected by ECP irradiation, as shown by FITC fluorescent staining, no statistical difference was found in any genotoxicity parameters.

We found an increase in the foci γ-H2AX parameter, one of the objective indicators of DNA breaks, and an increase in the foci 53BP1 parameter, which indicates the post-damage repair mechanisms after ECP. However, further in vitro, and in vivo studies are needed with large sample volumes to demonstrate the significance.