Acute and transient decrease in neutrophil count in transfusion-related acute lung injury: cases at one hospital

Transfusion-related acute lung injury (TRALI) is a rare but serious complication of blood transfusion. The syndrome is characterized by new acute lung injury developing during or within 6 hours of blood transfusion.

The study design was observational in nature.

All three cases of TRALI were associated with acute but transient decrease in the white blood cell (WBC) count. Implicated donors had HLA antibodies that matched the recipients' HLA antigens. The implicated units were a plateletpheresis in one case and fresh frozen plasma units in the other two. All implicated donors were multiparous women. The implicated antibody specificities were anti-HLA Class I and Class II in one case and anti-HLA Class II in the other two cases. Interestingly, patient neutrophil counts decreased by 80 to 90 percent in all three cases, including the two cases associated with HLA Class II antibodies.

An acute and transient decrease in WBC count may be a previously underrecognized feature of TRALI. A drop in the neutrophil count can occur even when the implicated antibodies have specificities to HLA Class II antigens, although they are expressed only on stimulated neutrophils. Based on the observations in these cases, it is recommended that a complete blood count and differential be obtained when TRALI is suspected. Further investigations into the mechanisms of the decrease in circulating neutrophils that is associated with infusion of HLA Class II antibody may yield new insights into the mechanism of TRALI.