Introduction: Damage to a cell and the loss of integrity of its cell membrane leads to the release of endogenous immunogenic molecules, which together are classified as “damage-associated molecular patterns” (DAMPs). Cell-free DNA (cf-DNA) released from nucleosomes may serve as a procoagulant cofactor and may be an important mediator of immunomodulatory and proinflammatory effects associated with blood transfusion. Objectives: To assess the levels of cf-DNA in supernatants of stored red cell components and the effect of leukoreduction and gamma irradiation on the release of cf-DNA during storage. Methods: This is a prospective cohort study on 99 stored red cell components, randomly divided into three groups – buffy coat (BC)-depleted, leuko-filtered (LP), and irradiated (IR) packed red blood cells. Red cell supernatants were drawn over a period of 21 days at three different time points (day 0, 7, and 21) from the study units. cf-DNA extraction was done and quantified by a bench top fluorometer. Change in cf-DNA content, rate of change (μg/day), and percent change were estimated and compared across different groups. Results: cf-DNA content increased (p = 0.000) with storage duration in the BC (median = 238.66 μg, interquartile range [IQR] = 168.42 on day 21 vs. median = 9.44 μg, IQR = 5.23 on day 0) and IR groups (p = 0.000) (median = 245.55 μg, IQR = 253.88 on day 21 vs. median = 7.07 μg, IQR = 13.58 on day 0), while there was a decreasing trend (p = 0.032) in the LP group (median = 4.55 μg, IQR = 10.73 on day 21 vs. median = 8.66 μg, IQR = 6.56 on day 0). The median rate of change in cf-DNA content (11.13 μg/day) and percent change in cf-DNA content (median = 4,106.16%) was highest in the IR group. Conclusions: Stored red cell components contain significant amount of cf-DNA. Release of cf-DNA is further aggravated by irradiation while leukoreduction leads to a decrease in cf-DNA content.
Comparison of UV spectrometry and fluorometry-based methods for quantification of cell-free DNA in red cell components