Long-term administration of high-dose deferoxamine 2 days per week in thalassemic patients.

OBJECTIVE: Compliance with parenteral administration of deferoxamine is often poor in thalassemic patients with iron overload. We tested the efficacy and tolerance of the drug at high dosage 2 d per week for 24 months in two adult thalassemic patients with permanently high serum ferritin using a portable pump and an implanted chamber. METHODS: Deferoxamine was administered using a pressure-operated portable pump through an implanted chamber. The patients were infused over 48 h every week with 198 mg/kg/d (patient 1) and 170 mg/kg/d (patient 2). Serum ferritin levels were measured at regular intervals. RESULTS: Serum ferritin decreased progressively from 2967 to 457 microg/L in patient 1 and from 6476 to 1951 microg/L in patient 2. Compliance and tolerance to treatment were excellent in the two patients. CONCLUSION: Intravenous administration of high-dose deferoxamine over 48 h per week using a portable pump and implanted chamber improved compliance in two thalassemic adult patients, resulting in a significant decrease in iron overload. We suggest that high-dose chelation therapy should be assessed in selected groups of iron-overload thalassemic patients receiving regular blood transfusions.

[Prevention of sickle cell crises with multiple phlebotomies]. / Prévention des crises douloureuses drépanocytaires par saignées itératives.

OBJECTIVES: Sickle cell disease patients suffering from frequent painful crises were submitted to phlebotomies in order to reduce hospitalization days due to pain, through hemoglobin (Hb) level reduction and iron deficiency in patients with an hemoglobin level equal to or above 9.5 g/dL. PATIENTS: Seven sickle cell disease patients (four SC, three SS), aged four to 24 years, were submitted to sequential phlebotomies during periods from 18 months to four years. METHODS: The number of hospitalization days for crises was considered. The volumes and frequencies of phlebotomies were adjusted according to the patients ages, the hemoglobin concentrations and the serum ferritin levels. RESULTS: One hundred and forty-four hospitalization days were recorded in the seven patients in the year preceding the treatment. During the study period, the annual numbers of hospitalization days were respectively 20, five, six and one. Mean hemoglobin concentration was 10.7 g/dL before phlebotomies and 8.8 to 9.2 g/dL during the four years of treatment. Mean corpuscular volume, mean corpuscular hemoglobin concentration and serum ferritin were also reduced. The volume of phlebotomies was 116 to 39 mL/kg/year according to the patients. COMMENTS AND CONCLUSION: The striking decrease of the number of hospitalization days for all the patients suggests a closed relationship between therapy and clinical improvement. The mechanism of this effect is probably multifactorial: a) the concentration of Hb level is known to influence the blood viscosity and its decrease always improved rheology in sickle cell disease patients; b) the mean corpuscular hemoglobin concentration is a critical factor concerning the HbS molecule polymerization in sickle cell disease, and its slight reduction may have an important biological effect. We observed these two biological modifications in our patients and suggest that they mediate the clinical effects. The iron deficiency induced by phlebotomies has no evident deleterious consequence either on height and weight in the children or on intellectual performance in any patients.

Bordetella holmesii isolated from a patient with sickle cell anemia: analysis and comparison with other Bordetella holmesii isolates.

OBJECTIVES: To analyze a Bordetella holmesii isolate from a patient with sickle cell anemia and to compare it with other B. holmesii strains and isolates and with strains of B. pertussis and B. bronchiseptica, two well-characterized species of the Bordetella genus. METHODS: The bacteriological characteristics and proteins produced by the B. holmesii isolate and the reference strain (ATCC 51541) were analyzed and compared with those of B. pertussis and B. bronchiseptica using sera from patients infected with B. pertussis, B. bronchiseptica or B. holmesii. RESULTS: The bacteriological characteristics of the B. holmesii isolate studied here were similar to those of the B. holmesii reference strain and other isolates. Some of the proteins produced by B. holmesii isolates were similar to those produced by B. pertussis and B. bronchiseptica, but none of these proteins was similar to the toxins and adhesins involved in the pathogenicity of B. pertussis and B. bronchiseptica. The phenotypic diversity of the proteins produced by B. holmesii isolates and the reference strain was striking. CONCLUSIONS: Our results suggest that either, the expression of B. holmesii proteins is regulated as in B. pertussis and B. bronchiseptica, with the B. holmesii strain exhibiting different phases, or the proteins produced in B. holmesii are different.