Leucocytosis in critically ill patients is not always a sign of infection!

Background

We observed a post-transfusion (PT) leucocytosis in several ICU patients, without showing other signs of sepsis. To prevent unnecessary investigations prompted by leucocytosis, and to understand the phenomenon, a prospective study was conducted.

Methods

Forty-five non-septic patients receiving a non-filtrated packed cells (NFPC) had a complete blood count (CBC) pre, and 2, 4, 6, 12 and 24 hours PT. Eleven patients multiply transfused, were randomly given NFPC or prestorage filtrated packed cells (PFPC), and CBC taken as above. IL-8, a leucocytes-chemoattractant, was measured in NFPC and PFPC stored for 1, 2, 3 and 4 weeks and in 16 NFPC just pre transfusion.

Results

White blood cell count (WBC) (× 10⁹/l) significantly increased 2 hours PT (19.5 ± 7.0 vs 14.3 ± 4.8 at baseline) (P < 0.05), and returned to baseline in 24 hours. In patients requiring more than one PC, WBC significantly increased 2 hours PT of a NFPC compared to baseline (24.2 ± 7.8 vs 16.8 ± 4.7) (P < 0.05), while when the same patients received PFPC, there was no such increase (14.9 ± 5.2 vs 13.9 ± 5.4). There was no change in IL-8 levels in PFPC stored for 1, 2, 3 and 4 weeks (mean 54 pg/ml) while there was a significant increase in IL-8 levels in NFPC (61, 59, 161, and 745 pg/ml, respectively). IL-8 levels were significantly higher in NFPC given to patients developing leucocytosis compared to patients who did not develop leucocytosis (408.4 ± 202 vs 70.4 ± 54.1 pg/ml) (P < 0.05).

Conclusions

Transfusion of packed cells may cause an acute and transient leucocytosis in critically ill non-septic patients. Leucocytosis occurred after transfusion of NFPC but not after transfusion of PFPC. We suggest that IL-8 may contribute to this phenomenon.