Management of obstructive sleep apnoea in children with modified monobloc appliances

AIM

This was to investigate the effect of the use of an orthodontic appliance in the treatment of obstructive sleep apnoea (OSA) in children using polysomnographic variables.

METHODS

10 boys and 10 girls with OSA aged between 4 to 8 years, referred from an otolaryngology clinic because of sleep apnoea, wore modified monobloc devices nightly for 6 months. Polysomnography was used for each patient for baseline diagnosis of OSA and also for post therapy assessment.

RESULTS

The median obstructive apnoea- hypopnoea index decreased after 6 months of therapy with oral appliances. The mean (+/-SD) number of episodes of OSA was 7.88+/-1.81 before treatment and 3.66+/-6.80 after 6 months (p<0.001).

CONCLUSIONS

The modified monobloc appliance is suggested for use in children with OSA and may be an effective therapeutic alternative in children with mild to moderate OSA.

Frequency of donor cytotoxic T cell precursors does not correlate with occurrence of acute graft-versus-host disease in children transplanted using unrelated donors

Bone marrow transplantation (BMT) from unrelated volunteers is frequently associated with both increased incidence and increased severity of acute graft-versus-host disease (GVHD). In the last years, it has been suggested that the analysis of the frequency of cytotoxic T lymphocyte precursors (CTLp) of unrelated HLA-matched donors can be used to detect disparity for HLA class I antigens and as a predictive test for development of severe GVHD. In this report, we summarized our experience regarding 20 pediatric patients affected by various hematological disorders, receiving allogeneic BMT from unrelated donors. HLA class I and II antigens of donor/recipient pairs were determined by means of serological typing, whereas molecular typing of HLA-class II antigens of patients and their potential donors was performed using PCR-SSP and PCR-fingerprinting techniques. CTLp values, estimated using limiting dilution analysis, were high (range, 1:7000-1:40,000) in 9 of 20 patients, while the other 11 children had low or undetectable levels (< 1:100,000) of CTL precursors. CTLp frequency was compared with the incidence and severity of GVHD observed after BMT. Our data demonstrate that the frequency of donor CTLp does not statistically correlate either with the occurrence of clinically significant acute GVHD or with disparity for HLA-class II molecular typing between donor and recipient. In particular, 4 of the 10 evaluable patients with an undetectable CTLp frequency developed grade IV, III, II, and IV acute GVHD, respectively. Although the limited number of subjects studied does not allow us to draw any firm conclusion, our data suggest a certain caution in considering this test suitable for the selection of potential donors.

Recombinant human G-CSF-mobilized peripheral blood stem cells for second allogeneic transplant after bone marrow graft rejection in children

Two children affected by severe aplastic anaemia and sickle cell anaemia rejected the allogeneic bone marrow transplantation from an HLA-matched unrelated volunteer and an HLA-identical sibling, respectively. In both cases a second transplant using granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood stem cells (PBSC) was performed. Donors were the HLA-haploidentical mother and the same HLA-identical sibling who was employed for the first marrow allograft, respectively. Treatment with G-CSF and PBSC collection were well tolerated. Both patients had engraftment of donor haemopoiesis and did not experience severe graft-versus-host disease. These cases confirm that PBSC transplant should be considered as a feasible treatment to reverse graft failure in paediatric patients.

Use of recombinant human granulocyte colony-stimulating factor in children given allogeneic bone marrow transplantation for acute or chronic leukemia

The role of recombinant human granulocyte colony-stimulating factor (rHuG-CSF) in myeloid recovery of children given an allogeneic bone marrow transplant (BMT) from an HLA-identical sibling for acute leukemia was evaluated in a retrospectively historically controlled study, involving 20 consecutive treated patients and 30 historical controls. In order to investigate the efficacy of rHuG-CSF in patients given a matched unrelated BMT with methotrexate as part of graft-versus-host disease (GVHD) prophylaxis, we also analyzed the kinetics of engraftment in eight further children with acute or chronic leukemia, transplanted using a volunteer donor. Patients were treated with 5 micrograms/kg/day of rHuG-CSF by 1-h intravenous infusion from day +5 until the absolute neutrophil count (ANC) was > or = 2 x 10(9)/l. No adverse effect related to treatment was observed in any patients. Children transplanted from an HLA-identical sibling and treated with rHuG-CSF reached an ANC count greater than 0.5 x 10(9)/l, 1 x 10(9)/l and of 2 x 10(9)/l in a significantly shorter time than the control group (day +9, +10 and +12, vs day +15, +22 and +29, respectively). An accelerated granulocyte production was also observed in patients receiving an unrelated transplant after a GVHD prophylaxis schedule including methotrexate, the median time to neutrophil recovery above 0.5 x 10(9)/l, 1 x 10(9)/l and 2 x 10(9)/l being +14, +15 and +17 days, respectively. In comparison to historical controls, all rHuG-CSF-treated patients had fewer days of fever, of antibiotic therapy and, only for children with HLA-compatible siblings, of hospitalization, whereas in the three groups the duration and severity of mucositis were comparable. No difference between the rHuG-CSF-treated patients and the historical controls given BMT from HLA-identical sibling was seen with regard to incidence of acute or chronic GVHD, relapse rate and actuarial event-free survival at day +100 and 1 year after transplantation. Our data suggest that in children given allogeneic BMT for acute or chronic leukemia, rHuG-CSF reduces duration of neutropenia, without increasing the rate of relapse or the incidence and severity of GVHD.

Juvenile chronic myelogenous leukemia: in vitro characterization before and after allogeneic bone marrow transplantation

In previously published studies on patients with juvenile chronic myelogenous leukemia (JCML), excessive proliferation of malignant monocyte-macrophage elements and impaired growth of normal hematopoietic progenitors were demonstrated. A selective hypersentivity of granulocyte-macrophage progenitors (CFU-GM) to granulocyte-macrophage colony stimulating factor (GM-CSF) seems to represent the main pathogenetic mechanism. Allogeneic bone marrow transplantation (BMT) has been demonstrated to be the only curative strategy for patients with JCML. In this study, we evaluated the growth of peripheral blood hematopoietic progenitors in semisolid cultures in two children with JCML before and after allogeneic BMT. Serum levels of GM-CSF, interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) were also assessed. IL-1-beta, GM-CSF and TNF-alpha serum levels of the patients before and after BMT did not differ significantly from those obtained in 45 healthy controls. After marrow transplant, the engraftment of donor hematopoietic stem cell was associated with the disappearance of both pretransplant GM-CSF hypersensitivity and CFU-GM spontaneous growth. The inhibitory effect on the growth of normal hematopoietic progenitors also resolved. This confirms that the substitution of the pathological hematopoietic progenitors represents the basis for the curvative effect of allogeneic BMT in the treatment of JCML, abolishing both the excessive responsiveness of JCML progenitor cells even to very low concentrations of GM-CSF and the growth-inhibitory effect on normal hematopoiesis.

Busulfan, cyclophosphamide and melphalan as conditioning regimen for bone marrow transplantation in children with myelodysplastic syndromes

As typical disorders of the elderly, myelodysplastic syndromes (MDSs) are relatively unusual in childhood. Nevertheless, up to 17% of cases of pediatric acute myeloid leukemia may have a preleukemic phase. In young patients, the goal of treatment is eradication of the preleukemic malignant clone and reconstitution of normal hematopoiesis. Allogeneic bone marrow transplantation (BMT) has proved to be capable of this, but the optimal conditioning treatment to achieve eradication remains to be defined. Between May 1989 and June 1993, eight consecutive pediatric patients with MDS received a marrow transplant from an HLA-identical, mixed lymphocyte culture (MLC) non-reactive sibling. Diagnosis at time of presentation was refractory anemia with excess of blasts (RAEB) in two patients, RAEB in transformation (RAEB-t) in three, and juvenile chronic myelogenous leukemia (JCML, the pediatric counterpart of adult chronic myelomonocytic leukemia) in the remaining three children. Conditioning regimen consisted of busulfan, cyclophosphamide and melphalan, three alkylating agents potentially capable of killing also dormant preleukemic stem cells. The preparative regimen was very well tolerated, and all patients engrafted promptly. Six out of eight patients (75%) are alive and well with a median observation time of 20 months (range 8-34 months). Serial karyotype monitoring and molecular analyses have demonstrated a full chimerism of donor cells and the complete disappearance of trisomy 8 detected before transplant in three cases. All surviving patients have a Karnofsky score of 100%. One boy, affected by RAEB-t with monosomy 7 resistant to treatment with low-dose ara-C, relapsed 11 months after BMT, evolved in AML and died from progressive leukemia. Another patient with RAEB died on day +95 after BMT due to interstitial pneumonia of unclear etiology. This study confirms that allogeneic BMT is the treatment of choice in pediatric patients with MDS, and suggests that the employed conditioning regimen is a safe and effective means for eradicating the preleukemic malignant clone. Particularly noteworthy is that the three children with JCML obtained a complete remission and one of them is now a long-term survivor.

Use of recombinant human erythropoietin after bone marrow transplantation in pediatric patients with acute leukemia: effect on erythroid repopulation in autologous versus allogeneic transplants

We carried out a pilot study on the use of recombinant human erythropoietin (rHuEPO) in children undergoing allogeneic or mafosfamide-purged autologous BMT for ALL or AML. rHuEPO was administered intravenously at a dose of 75 U/kg/day for 30 days after transplant. Ten rHuEPO-treated patients receiving allogeneic BMT and 10 given autologous BMT were compared with 15 allogeneic and 10 autologous historical controls. Endogenous EPO production was appropriate for the degree of anemia after autologous BMT. In these patients, rHuEPO did not accelerate erythroid repopulation and did not modify transfusion requirements. With allogeneic BMT, erythroid marrow activity increased faster in patients given rHuEPO than in controls and resulted in higher red cell production, the mean reticulocyte count on day +30 being 187 +/- 51 x 10(9)/l in treated patients versus 107 +/- 63 x 10(9)/l in controls (p < 0.01). The total number of RBC units administered was 1.7 +/- 1.3 in the rHuEPO group versus 5.1 +/- 3.0 in the control group (p < 0.001). The total number of platelet transfusions was 4.0 +/- 2.3 for patients given allogeneic BMT and receiving rHuEPO versus 8.4 +/- 6.8 for historical controls (p < 0.05) whereas it was similar in rHuEPO-treated and control autologous BMT patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Translocation (8;21) in two cases of refractory anemia with excess of blasts in transformation

We report two cases of refractory anemia with excess of blasts in transformation (RAEB-T) with the translocation (8;21), which is frequent in ANLL but not in myelodysplastic syndromes (MDS). A review of such cases leads us to conclude that myeloproliferative disorders characterized by the t(8;21) may be preceded by an MDS phase.

Recombinant human granulocyte-macrophage colony stimulating factor (rHuGM-CSF) in cyclic neutropenia

We describe the case of a 12-year-old boy affected by cyclic neutropenia, at high risk of developing life-threatening infections, treated with recombinant human granulocyte-macrophage colony stimulating factor (rHuGM-CSF). The drug was effective in reducing the severity of neutropenia and infectious complications in our patient. It was administered for brief periods of time, in contrast to the daily continuous administration reported for rHuG-CSF. Therefore, more extensive studies must be performed to identify the most effective time schedule for the drug. In vitro studies of hemopoietic progenitor cells were useful, in this case, to predict treatment response.

Factors leading to the appearance, after BMT, of cytotoxic antibodies against T, B and activated T lymphocytes: critical appraisal

In order to investigate the role of lymphocytotoxic antibodies, acquired after allogeneic and autologus bone marrow transplantation, we studied 309 sera from 42 transplanted patients (16 adults and 26 children). We tried to correlate antibody elicitation towards T, B and activated T lymphocytes with the following parameters: genetic (recipient's and donor's sex, HLA profile), clinical (recipient's primary disease, GvHD, transplant outcome) and technical (bone marrow purging, auto-or allotransplant). There is evidence that anti-T and -B cytotoxic antibodies appear earlier than anti-activated T antibodies. Anti-HLA specific antibodies seem to be produced by the transfusional stimulus: they appear early after BMT and wane after the first year. Humoral responsiveness seems to be age related (adults are more responsive than children) and conditioned by GvHD (the level of cytotoxic antibodies decreases when GvHD is prevented by bone marrow purging). The level of cytotoxicity is significantly lower in the sera of autotransplanted patients compared with the allotransplanted ones. It appears that anti-activated T antibodies are produced by cell activation at different times in adults and children: in adults this occurs during GVHD and in children during the relapse of disease.

[Fluorometric method for the assay of IgG produced in lymphocyte cultures]

We have studied the IgG secreted in a system of CML. Microquantity of IgG (30-3000 micrograms/ml) of culture was determined using a fluorometric method based on the determination of the fluorescence derived by immune-complex IgG-FITC labeled goat Anti-human antibody to IgG covalently coupled to hydrophilic beads. This techniques has showed a good sensibility and accuracy.