Can Dialyser Reactions Lead to Raised WBC Counts?
Yes, dialyser reactions can cause transient leukopenia (decreased WBC) rather than leukocytosis (raised WBC), though the inflammatory response to dialysis membranes can be associated with elevated neutrophil counts over time in hemodialysis patients.
Acute Dialyser Reactions and WBC Changes
Type A and Type B Reactions
Dialyser reactions are classified into two categories with distinct WBC patterns 1:
- Type A (hypersensitivity reactions): Occur in approximately 4 per 100,000 patients and can cause acute leukopenia, thrombocytopenia, and oxygen desaturation 1
- Type B (nonspecific reactions): Occur in 3-5% of patients with similar hematologic changes 1
Acute Leukopenia During Dialysis
The immediate response to dialyser exposure typically involves leukopenia, not leukocytosis 1. This occurs through:
- Complement activation via the alternate pathway when blood contacts dialysis membranes 2
- Pulmonary leukostasis: White blood cells become sequestered in the pulmonary circulation during the initial phase of dialysis 1
- Granulocyte dysfunction: Impairment of phagocytosis, adhesion, and reactive oxygen species formation 2
Chronic Inflammatory Response and Elevated WBC
Long-term Hemodialysis Effects
While acute reactions cause leukopenia, chronic hemodialysis is associated with elevated WBC counts through persistent inflammation 2:
- Neutrophil counts correlate with mortality: Two large studies of 7,719 and 25,661 hemodialysis patients demonstrated a direct association between elevated neutrophil counts and increased mortality 2
- Chronic inflammation markers: Elevated C-reactive protein, IL-6, and other inflammatory biomarkers are common in dialysis patients and correlate with WBC elevation 2
Mechanisms of Chronic WBC Elevation
The sustained inflammatory state in dialysis patients results from 2:
- Membrane biocompatibility issues: Unmodified cellulose membranes activate complement more than synthetic membranes, promoting cytokine production 2
- Endotoxin passage: Certain membranes allow pyrogens from contaminated dialysate to enter the bloodstream, stimulating peripheral blood mononuclear cells 2
- Persistent inflammatory triggers: Clotted access grafts, failed kidney grafts, and recurrent infections contribute to chronic inflammation 2
Clinical Interpretation
Timing Matters
The WBC response depends on when you measure 1, 3:
- During/immediately after dialysis: Expect transient leukopenia from sequestration and complement activation
- Between dialysis sessions: Chronically elevated WBC (mean 6.4 ± 1.8 × 10³/µL in maintenance hemodialysis patients) reflects ongoing inflammation 3
Prognostic Significance
Elevated WBC in hemodialysis patients predicts poor outcomes 3:
- All-cause mortality: Hazard ratio 1.228 per unit increase in WBC (95% CI: 1.095-1.378)
- Cardiovascular mortality: Hazard ratio 1.242 (95% CI: 1.046-1.475)
- Infection-related mortality: Hazard ratio 1.252 (95% CI: 1.066-1.470)
Common Pitfalls
Don't Confuse Acute vs. Chronic Responses
- Acute dialyser reactions cause leukopenia with dyspnea and burning sensations 1
- Chronic dialysis-related inflammation causes leukocytosis between treatments 3
Membrane Selection Matters
- Synthetic membranes (polysulfone, polyacrylonitrile, polyamide) cause less complement activation than unmodified cellulose membranes 2
- High-flux synthetic membranes paradoxically allow less endotoxin passage despite larger pore size 2
Rule Out Other Causes
Before attributing elevated WBC to dialysis-related inflammation, exclude 4:
- Infection: Most common cause of leukocytosis in any patient
- Medications: Corticosteroids, lithium, beta agonists
- Physical/emotional stress: Can elevate WBC independent of dialysis
- Primary bone marrow disorders: Suspect if WBC >100,000/mm³ or concurrent red cell/platelet abnormalities