126 - PREVALENCE AND ASSOCIATED FACTORS FOR CYTOPENIAS WITH ACUTE KAWASAKI DISEASE

Background: Cytopenias are sometimes observed in patients with acute KD, and may be related to inflammation, concomitant infection, treatment and other factors.

Methods: Patients assessed at the Hospital for Sick Children, Toronto, for acute KD from 1995 to 2023 were included if results from a complete blood count assessment were available. The lower limit for age/sex-related normal values for hematologic cell lines was taken from the SickKids CALIPER Project (caliper.research.sickkids.ca). We determined the prevalence, and associations with demographics, clinical and laboratory features, treatment and CA outcomes.

Results: Of 1549 eligible patients, 773 (50%) were cytopenic in at least one cell line at presentation, including WBC for 5.4%, neutrophils 3.9%, lymphocytes 28.3%, platelets 14.6% and RBCs for 37.7%, with 7 patients cytopenic in all 5 cell lines. For demographics, RBC cytopenia and lymphopenia were associated with younger age, with RBC cytopenia less prevalent for males, and few associations with ethnicity. Patients with WBC cytopenia and thrombocytopenia had few KD criteria, with cytopenia for each of all 5 cell lines associated with a greater likelihood of shock, ICU admission and inotropes (FIGURE). Lymphopenia and thrombocytopenia were associated with a greater likelihood of concomitant infection. WBC cytopenia and neutropenia were associated with lower levels of inflammatory markers, with RBC cytopenia and lymphopenia associated with higher levels. Treatment with both IV and oral steroids were associated with cytopenia for each of all 5 cell lines. Greater CA involvement was associated with lymphopenia only.

Conclusions: Cytopenias are prevalent at presentation and vary across cell lines, with few associations with patient demographics. However, cytopenia in any cell line was associated with a greater likelihood of severe presentation. Concomitant infection had limited associations, and variable associations with inflammatory markers. The presence of cytopenias was associated with greater immunomodulatory therapy, perhaps another indicator of greater disease severity. Nonetheless, cytopenias other than lymphopenia were not associated with greater CA involvement, despite more severe disease.