Therapeutic leukapheresis with severe pertussis: evaluating efficacy, feasibility, and safety

Severe pertussis with hyperleukocytosis (WBC ≥ 50 × 10⁹/L) carries high mortality in infants. While exchange transfusion (ET) is a commonly recommended intervention, it is resource-intensive and non-selective. Therapeutic leukapheresis (TL) offers targeted leukoreduction but lacks robust pediatric evaluation in pertussis. We assessed TL's efficacy, safety, and feasibility compared to ET.

This retrospective analysis enrolled children aged ≤ 4 years hospitalized with severe pertussis from Jan 1st 2024 to May 31st 2024. Patients were stratified into three groups: 4 patients underwent TL alone (Primary TL), 4 patients received ET alone (ET Only), and 6 patients received both (Salvage TL) due to refractory disease. We compared clinical characteristics, hematological responses, resource utilization, and survival outcomes.

Primary TL reduced median WBC counts from 50.6 to 24.8×109/L. ET Only reduced WBC from 43.0 to 25.6×109/L. In the Salvage TL group, TL succeeded in lowering WBC counts (median reduction 56.4%) where prior ET had failed. Resource utilization differed markedly: ET required substantial blood products (median 2.75 U RBCs, 200 mL plasma), whereas Primary TL utilized a fixed 1.5 U RBC volume for circuit priming to prevent dilutional anemia, with no plasma consumption (p=0.02). Post-treatment platelet (PLT) counts were comparable between Primary TL and ET groups (p=1.000). Although two deaths (20% of total TL procedures) occurred, both were in the Salvage group (33.3% mortality). The Primary TL group had a 0% mortality rate, identical to the ET Only group.

TL demonstrates robust leukoreduction efficiency and significant blood resource conservation compared to ET. Safety outcomes for Primary TL were equivalent to ET. Mortality was driven by refractory disease in salvage cases. TL represents a viable, blood-sparing alternative for severe pertussis.