Disease severity of children with hereditary spherocytosis predicts the clinical course of aplastic crisis.

Transient aplastic crisis (TAC) is a known complication of hereditary spherocytosis (HS), typically triggered by parvovirus-B19. However, in children with HS, the occurrence, clinical course and predictors of TAC severity remain incompletely defined. We aimed to characterize the clinical and hematologic features of TAC and to identify factors associated with its severity. We conducted a single-center retrospective cohort study of children with HS, analyzing clinical presentation, laboratory parameters, and outcomes. Associations between baseline disease severity and TAC course were assessed using correlation analyses and multivariable logistic regression. We studied 123 children with HS of whom 61 (49.6%) experienced TAC (median age 6.6 years, interquartile range (IQR) 4.56-8.18). Pancytopenia was observed in 28 (50.9%) of 55 patients with complete data and was associated with a lower mean nadir hemoglobin level (5.3 ± 1.0 vs. 5.9 ± 0.8g/dL, p = 0.009) and a higher transfusion requirement (median 2, IQR 1.8-2 vs. 1, IQR 1-2 units, p < 0.001). Acute parvovirus-B19 infection was confirmed in 94.4% of those tested. Lower baseline hemoglobin (ρ = - 0.26, p = 0.039) and higher baseline reticulocyte percentage (ρ = 0.52, p < 0.001) correlated with greater transfusion requirements. Baseline HS characteristics were more severe in patients who developed pancytopenia during TAC. In multivariable analysis, higher baseline reticulocyte percentage and older age at crisis were independently associated with greater TAC severity. All the patients achieved complete hematologic recovery.

conclusionTAC-related pancytopenia is common in children with HS. Baseline hemolytic severity is associated with a more severe clinical course of TAC, supporting risk-adapted monitoring and management during aplastic crisis. WHAT IS KNOWN: • Transient aplastic crisis (TAC) is a recognized complication of hereditary spherocytosis, most commonly triggered by parvovirus-B19. • TAC is classically described as pure red cell aplasia but may be accompanied by additional cytopenias. WHAT IS NEW: • In the largest pediatric cohort to date, pancytopenia occurred in about half of TAC events and was associated with increased transfusion requirements. • Baseline hemolytic severity predicted the clinical course of TAC, including pancytopenia and transfusion requirements, supporting risk-adapted monitoring.