Non-Deletional HbH Disease (--/αTα): When On-Demand Transfusion Has Not Restored Target Haemoglobin
This protocol applies to patients with the non-deletional form of Haemoglobin H disease (genotype --/αTα)
in whom on-demand transfusion therapy has failed to reliably maintain the target haemoglobin level.
Clinical Scenario
Non-deletional HbH disease (--/αTα) presents with a diverse clinical course;
however, symptoms are generally more severe than those seen in deletional forms of HbH disease.
Patients in this sub-group have a persistent, severe phenotype requiring escalation of transfusion support.
Previous Treatment — Failure Condition
The prior approach was on-demand transfusion of leucocyte-depleted red blood cells,
administered when haemoglobin fell below 70 g/L or in the presence of symptomatic anaemia,
with the goal of restoring haemoglobin to 80–90 g/L. This protocol is indicated when
that haemoglobin target is not reliably achieved or sustained on the on-demand strategy.
Next-Line Approach
For patients with a persistent severe phenotype where on-demand transfusions are insufficient,
a scheduled (regular) transfusion regimen is recommended as the next step —
with the clinical goal of maintaining pre-transfusion haemoglobin at 80–90 g/L.
The complete protocol, including scheduling intervals, monitoring parameters, and decision thresholds,
is available in the full regimen below.
References
- Clinical phenotypes are diverse among affected individuals with non-deletional haemoglobin H (HbH) disease (--/αTα).
- Clinical symptoms of non-deletional HbH are generally more severe than those of deletional forms.
- A transfusion regimen is recommended for those patients with a persistent score of ≥4 (severe phenotype) over a period of 3 to 6 months.
- Once initiated, blood transfusions should be scheduled, usually every 3 to 6 weeks, with pre-transfusion haemoglobin aimed at a slightly lower level (80–90 g/L) in comparison to that aimed for β-TM.
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