Bone marrow transplantation for T-B- severe combined immunodeficiency disease in Athabascan-speaking native Americans

A distinct form of autosomal recessive T-B- severe combined immunodeficiency disease occurs with a high frequency among Athabascan-speaking Native Americans (SCIDA), including Navajo and Apache Indians from the southwestern US and Dene Indians from the Canadian Northwest Territories. The SCIDA gene has been linked to markers on chromosome 10p although its identity and role in the pathogenesis of this disease are unknown. We report our experience in treating 18 Navajo and Dene children with SCIDA between 1984 and 1999; 16 underwent bone marrow transplants (BMT). All children were symptomatic within 2 months of birth, had the T-B- NK(+)SCID phenotype and 67% presented with oral and/or genital ulcers. Three children had evidence of maternal engraftment prior to transplant. Two children died shortly after diagnosis. Three children required more than one BMT and 12 are alive with T cell reconstitution at a median follow-up of 7 years. Three children developed normal B cell immunity, two of whom received ablative conditioning therapy with either radiation or busulfan. Three of the four children who died received therapy with either radiation or busulfan and two of eight long-term survivors who were also recipients of cytotoxic chemotherapy have failed to develop secondary teeth. These results demonstrate the efficacy of BMT in treating infants with this distinct form of SCID, although B cell reconstitution remains a problem even with HLA-matched donors. Without conditioning, T cell engraftment is likely when closely HLA-matched donors are used. With T cell depletion of haplocompatible marrow, conditioning with immunosuppressive therapy may be necessary; however, children with SCIDA who were treated with intensive immunosuppressive and myeloablative therapy had a poor outcome.

Extracutaneous Sweet syndrome involving the gastrointestinal tract in a patient with Fanconi anemia

Acute febrile neutrophilic dermatosis, or Sweet syndrome, is a cutaneous eruption characterized clinically by the appearance of painful red plaques and nodules and histologically by an intense dermal neutrophilic infiltrate. Extracutaneous manifestations are rare. We report a patient in whom otherwise typical cutaneous Sweet syndrome was accompanied by an extracutaneous manifestation in the ileum.

Comparative genomic hybridization in pediatric acute lymphoblastic leukemia

Comparative genomic hybridization (CGH) was used to clarify the chromosomal status of 15 patients diagnosed with childhood acute lymphoblastic leukemia (ALL). Bone marrow samples from 10 of the 15 patients were selected because no metaphases were obtained for cytogenetic analysis. Three patients with normal trypsin and giemsa banding (GTG) karyotypes were also studied by CGH to determine whether significant abnormalities might have been missed by banding analysis, and samples from an additional 2 patients with hyperdiploidy were also included. Seven of the 10 patients with failed GTG banding analysis were found to be chromosomally abnormal by CGH; 2 out of 3 patients with normal GTG band karyotypes were abnormal, indicating that the metaphases available for karyotyping were not malignant cells, and that CGH analysis of hyperdiploid samples provided more accurate resolution than karyotyping alone. The prognostic value of chromosomal aberrations detected by CGII and the efficiency of the technique suggest a central role for CGH in routine clinical cytogenetics.

Oral and genital ulceration: a unique presentation of immunodeficiency in Athabascan-speaking American Indian children with severe combined immunodeficiency

BACKGROUND

Oral and genital ulcerations have been previously reported in 3 Navajo children diagnosed with severe combined immunodeficiency disease with T- and B-cell lymphopenia (T-B(-)-SCID).

OBJECTIVE

To evaluate the occurrence of oral and genital ulcerations in 12 Athabascan-speaking American Indians with a diagnosis of T-B(-)-SCID (SCIDA group) and to compare their occurrence in non-Athabascan-speaking children with SCID (control group). We also observed the course of these ulcerations in response to bone marrow transplantation (BMT).

DESIGN

Retrospective survey of the medical records of patients with SCID admitted from December 1, 1986, through July 31, 1995.

SETTING

Pediatric Bone Marrow Transplantation Division at a university hospital.

PATIENTS

Twelve children in the SCIDA group and 21 in the control group. All patients had virtual absence of T- and B-cell numbers and function at time of diagnosis.

RESULTS

Oral and/or genital ulcers developed as a presenting feature of the SCIDA group. These ulcerations were not observed in the 21 controls. All patients underwent BMT. Of the 10 patients with oral and/or genital ulcerations, 3 had poor T-cell reconstitution after BMT, with recurrences of ulcers requiring additional BMTs.

CONCLUSIONS

Oral and/or genital ulcerations are common in Athabascan-speaking American Indian children with T-B(-)-SCID but are not seen in non-Athabascan-speaking children with SCID. Thus, oral and/or genital ulceration appears to be an important, distinctive finding, and often a presenting feature of immunodeficiency in Athabascan-speaking American Indian children with SCID. Bone marrow transplantation with successful T-cell engraftment appears to be curative in the resolution of the ulcers, with recurrences only in patients who had poor T-cell reconstitution.

Dose reduction of chemotherapeutic agents after weight loss

The aim of dose reduction of chemotherapeutic agents following weight loss is to avoid excessive toxicity while maintaining an equivalent therapeutic effect. Several methods of calculating this dose reduction are currently in use, including dose reduction in proportion to the reduction in body surface area (BSA) or the amount of weight lost and no dose reduction unless significant toxicity occurs. Each of these methods results in the administration of a different dose and therefore different drug exposure, as measured by the area under the time versus concentration curve (AUC). We have used pharmacokinetic modeling software and normative data on the pharmacokinetics of high-dose methotrexate to determine the change in AUC resulting from dose reduction by each of the methods cited for patients with weight loss. Dose reduction in proportion to the reduction in weight results in the same AUC and therefore equivalent drug exposure as before weight loss. In contrast, the more common practice of dose reduction in proportion to the decrease in BSA (as determined by recalculating BSA) results in a higher AUC than before weight loss. This results in increased drug exposure and potentially increased toxicity, which may be avoided if dose reduction is carried out in proportion to the decrease in weight rather than in BSA. The same principles are applicable to other drugs, particularly those associated with dose-dependent toxicity.

Bone marrow transplantation for inherited diseases

Allogeneic bone marrow transplantation has been used successfully for the treatment of a variety of inherited diseases. The goal of transplantation in this setting is to provide a sufficient degree of sustained marrow engraftment to allow longterm amelioration of the inherited disease phenotype. Many factors influence the likelihood of achieving this goal, including donor availability, conditioning regimen, marrow processing, and the nature and extent of progression of the disease. For many inherited diseases early diagnosis is imperative because the outcome of transplantation is more favorable when performed prior to the development of significant organ damage from the disease, its complications, or treatment. Although the results of bone marrow transplantation are good for some inherited diseases and are improving for others, significant problems remain such as donor availability, conditioning regimen toxicity, graft failure, and graft-versus-host disease. This review describes some of the unique features of bone marrow transplantation for inherited diseases and discusses recent advances in this area.

Maternal mosaicism for a novel interleukin-2 receptor gamma-chain mutation causing X-linked severe combined immunodeficiency in a Navajo kindred

X-linked severe combined immunodeficiency disease (SCID) results from mutations of IL2RG, the gene encoding the interleukin-2 receptor gamma chain, also known as the common gamma chain (gamma c). A distinct form of autosomal recessive SCID occurs at an increased frequency among the Navajo Native American population. The disease gene responsible for autosomal Navajo SCID remains to be determined. We report the occurrence of X-linked SCID in a Navajo Native American kindred with two affected brothers. X-linked SCID was suggested by the presence of circulating B cells and the absence of surface gamma c expression in a cell line derived from an affected male. A C-to-T transition was demonstrated in exon 5 of the IL2RG gene, resulting in the substitution of tryptophan for arginine at position 224. This change was not present in the peripheral blood lymphocytes of the mother, thus proving the occurrence of a new mutation in the maternal germline. This report underscores the importance of establishing a specific genetic diagnosis for SCID cases and illustrates the inherent difficulties in providing genetic counseling in cases involving mosaicism.

Genetic analysis and functional characterization of prothrombins Corpus Christi (Arg382-Cys), Dhahran (Arg271-His), and hypoprothrombinemia

The structural abnormalities and functional characteristics of dysfunctional prothrombin variants in two new kindreds have been determined. Prothrombin Corpus Christi (family 1) was purified and found to have markedly reduced fibrinogen clotting activity, yet normal amidolytic and near-normal platelet aggregating activity. A transition (C to T) at nucleotide position 8885, present in the heterozygous form in affected family members, resulted in the substitution of Cys for Arg 382. This substitution results in the loss of a positive charge within the fibrinogen-binding exosite of thrombin, thus accounting for the observed functional defect. A heterozygous C to T transition was also present at position 19994 in other family members with a hypoprothrombinemic phenotype. This mutation results in the replacement of Gln 541 (CAA) by a premature stop codon (TAA). Prothrombin Dhahran (family 2) was found to have markedly reduced fibrinogen clotting activity, but normal amidolytic activity. Affected family members were found to have a G to A transition at nucleotide position 7312 resulting in the substitution of His for Arg 271. This substitution results in the abolition of a factor Xa cleavage site, yielding meizothrombin rather than thrombin, on activation of prothrombin Dhahran by factor Xa. All but one of the above mutations occur at CpG dinucleotides, thus further supporting the observation of a high incidence of CpG transitions in hereditary dysprothrombinemia. The significant bleeding tendencies of individuals homozygous for prothrombin Dhahran (prothrombin clotting activity 5% to 7%) contrast sharply with the absence of significant chronic bleeding in the proband expressing prothrombin Corpus Christi (prothrombin clotting activity 2%). Our findings underscore the capacity of thrombin to contribute to clinical hemostasis by mechanisms other than its fibrinogen clotting activity.

Yield of positive blood cultures in pediatric oncology patients by a new method of blood culture collection

BACKGROUND

The optimal number of blood cultures and the volume of blood for pediatric blood cultures have not been defined. In 1990 such criteria were established at our institution. We retrospectively reviewed records of all pediatric oncology patients who were admitted for febrile episodes in 1989 and in 1991 and 1992 to determine whether there was an increase in the detection of bacteremia and fungemia.

METHODS

Blood was drawn via venipuncture and central intravascular catheters and inoculated into the designated blood culture bottles. Each patient had a minimum of two separate blood draws, i.e. two separate cultures; the volume was determined by the patient's weight. In all cases < 1% of the patient's blood volume was drawn per culture. Patients' records were reviewed regarding type of malignancy, chemotherapy and neutropenia.

RESULTS

The rate of bacteremic patients increased from 12% (13 of 113) in 1989 to 22% (27 of 123) in 1991. This increase continued through 1992 with 23% (27 of 118) of patients having positive blood cultures. Gram-positive bacteria predominated throughout the study period.

CONCLUSIONS

Although factors such as more aggressive chemotherapy or a different spectrum of malignant diseases may contribute to the statistically significant increase in identification of bacteremic patients, a standardized method of blood culture collection is merited. The consistent volumes of blood per culture and the minimum of two cultures per febrile episode follow the principles of blood culture collection established for adults. The same principles should apply to pediatric patients.

Successful treatment of intrathecal methotrexate overdose by using ventriculolumbar perfusion and intrathecal instillation of carboxypeptidase G2

Prompt and appropriate management measures are critical in order to achieve a favorable outcome after a major overdose of intrathecally (IT) administered methotrexate (MTX). Published information available to guide clinicians in the immediate management of this medical emergency is scant. Herein we describe a 6-year-old boy with acute lymphoblastic leukemia who received an inadvertent overdose of 600 mg of IT administered MTX instead of the intended dose of 12 mg. Severe acute neurotoxicity developed rapidly. Lumbar puncture and drainage of 15 mL of cerebrospinal fluid 2 hours after administration resulted in removal of 32% of the administered drug. Ventriculolumbar perfusion with 240 mL of warmed isotonic saline through ventricular and lumbar catheters for 3 hours resulted in removal of a total of 90% of the drug within 8 1/2 hours after administration. IT administration of 2,000 U of carboxypeptidase G2 (CPDG2), an enzyme that inactivates MTX, resulted in a further 150-fold reduction in cerebrospinal fluid MTX concentration. The patient experienced complete recovery. To our knowledge, this is the first reported case of the use of IT instillation of CPDG2 for the treatment of an overdose of IT administered MTX in a human, and it is only the second reported favorable outcome after an IT overdose of more than 500 mg of MTX. Minor IT overdoses of MTX can be managed by immediate lumbar drainage alone. Major overdoses may also necessitate prompt ventriculolumbar perfusion, IT instillation of CPDG2, and further supportive measures for a successful outcome after this infrequent but potentially catastrophic event.

Aromatase expression in human germinomas with possible biological effects

Gonadal aromatase expression has been demonstrated in human Leydig, granulosa, and thecal cells, but never in human germ cells. In an attempt to explain the unique occurrence of isosexual precocious puberty in a young girl with a hCG-secreting suprasellar germinoma, we demonstrated the presence of aromatase expression in the germ cell component of this tumor. Immunohistochemical staining for P450-aromatase and hCG using a peroxidase-labeled streptaviden-biotin technique was performed on tumor specimens from the above patient and from four other subjects with central nervous system germinoma. Cytoplasmic aromatase staining was present in the germinoma cells of four of five cases of central nervous system germinoma studied. Staining was absent in the lymphocytic element within the tumor and in negative control tissues. The demonstration of aromatase activity in the malignant element of human germinomas indicates that aromatase expression can occur in human germ cells after malignant transformation. This parallels the finding that the transformation of Sertoli cells to sex cord tumor with annular tubules in Peutz Jeghers syndrome is associated with the induction of marked aromatase expression and systemic estrogen effect. We propose that tumor aromatase played a similar role in the unique occurrence of isosexual precocity in a girl with a suprasellar germinoma.

Successful resection of thoracic aortic aneurysms in Wiskott-Aldrich syndrome

A 23-year-old man with Wiskott-Aldrich syndrome, chronic aortitis, and severe aneurysmal dilatation of the thoracic aorta successfully underwent two-stage graft replacement of the ascending and descending thoracic aorta. Nine years postoperatively, he is asymptomatic and employed full time.

Variation in the practice of dose reduction of chemotherapeutic agents after weight loss or amputation

PURPOSE

Dose reduction of chemotherapeutic agents in response to weight loss or amputation is important in avoiding excessive therapy-related toxicity. Several methods of calculating this dose reduction are currently in use, including dose reduction in proportion to (a) the reduction in body surface area (BSA), (b) the amount of weight lost, and (c) no dose reduction unless toxicity is observed. Each of these methods results in the administration of a different dose, and few guidelines exist as to the preferred method.

METHODS

We conducted a survey of a large group of pediatric oncologists, pediatric oncology nurses, and data managers to determine the methods of dose reduction currently in use for patients (a) with weight loss, (b) after amputation, and (c) with further weight loss after amputation.

RESULTS

Responses were obtained from 237 of 294 individuals surveyed (80.6%). The most popular method was to dose reduce in proportion to the reduction in BSA in patients with weight loss alone (88%), amputees (60%), and amputees with ongoing weight loss (66%). Other methods were chosen by 7%, 31%, and 24% of participants in each of these clinical settings, respectively.

CONCLUSION

The chosen methods result in a discrepancy of administered doses of up to 37%. Our results highlight the need for the standardization of practice, and the determination of the optimal method of dose reduction after weight loss or amputation.

Aqueous vasopressin infusion during chemotherapy in patients with diabetes insipidus

BACKGROUND

Patients who have suprasellar germinomas in childhood often present with central diabetes insipidus (CDI). The authors investigated the use of aqueous vasopressin (AVP) by continuous infusion to control the fluid and electrolyte balance in germinoma patients with CDI during aggressive fluid hydration as a part of a preirradiation chemotherapy protocol.

METHODS

Three patients with suprasellar germinomas and CDI were treated with four courses of preirradiation chemotherapy. Two patients were treated with a continuous AVP infusion at an initial rate of 0.08-0.10 mU/kg per hour during hydration. Fluid intake, urine output, body weight, urine specific gravity, and serum electrolyte concentrations were monitored closely, and the infusion rate was adjusted accordingly.

RESULTS

Very low dose AVP infusion controlled fluid balance while allowing appropriate diuresis during chemotherapy. Fluid intake and output were markedly less in the AVP-treated patients (3.8 L/m2 per day) than in the untreated patient (20 L/m2 per day).

CONCLUSIONS

The use of very low dose AVP infusion at an initial rate of 0.08-0.10 mU/kg per hour during hydration therapy allowed easily titratable control of fluid and electrolyte balance in the patients studied and avoided the complications associated with desmopressin acetate antidiuresis or withholding antidiuretic treatment altogether.

Successful hemostasis during a major orthopedic operation by using recombinant activated factor VII in a patient with severe hemophilia A and a potent inhibitor

The treatment of bleeding episodes and the provision of perioperative hemostasis in patients with hemophilia in whom coagulation factor inhibitors have developed are a major therapeutic challenge because ordinary replacement therapy is usually ineffective. Herein we report the use of recombinant activated factor VII (rFVIIa) in providing successful hemostasis in a patient with hemophilia A and a high-titer inhibitor to factor VIII during a major orthopedic operation. rFVIIa (102 micrograms/kg) was administered intravenously every 2 to 3 hours for a total of 9 days. No excessive bleeding occurred intraoperatively or postoperatively, and no adverse effects attributable to rFVIIa were observed. This surgical procedure probably represented a greater hemostatic challenge than any previously reported operation in which rFVIIa was used. Thus, this article adds considerably to the growing body of literature that suggests the safety and efficacy of rFVIIa in providing perioperative hemostasis and treating severe bleeding episodes in patients with hemophilia and inhibitors refractory to other treatment modalities.

Tilt-table testing and oral metoprolol therapy in young patients with unexplained syncope

OBJECTIVE

Tilt-table testing is useful for investigating unexplained syncope in pediatric patients. No data are available on the use of intravenous metoprolol during testing to identify children who might respond to subsequent oral beta-adrenergic blockade or on the efficacy and safety of such oral therapy.

DESIGN

To provide these data, we obtained follow-up information on 27 consecutive pediatric patients who had tilt-table testing for unexplained syncope.

RESULTS

Nineteen patients (70%) had positive test results with or without isoproterenol infusion. All these patients had negative test results after intravenous infusion of metoprolol and subsequently were treated with oral metoprolol. Taking oral metoprolol therapy alone, 9 (47%) of the 19 patients were asymptomatic, 8 (42%) reported a decreased frequency of syncopal episodes, and 2 (11%) had unchanged or more frequent episodes. The mean dosage of metoprolol required to prevent symptoms was 1.5 mg/kg per day. Mild side effects were reported by 6 (32%) of the 19 patients. Six patients (32%) required additional medications.

CONCLUSIONS

We conclude that metoprolol is safe and effective for the treatment of most cases of neurocardiogenic syncope in children and that this response cannot be predicted accurately by the use of intravenous metoprolol during testing.

Estimating the predictive value of a diagnostic test. How to prevent misleading or confusing results

The diagnostic process consists of a series of steps in which the estimated probability of particular disease is increased or decreased until either treatment can be instituted or the diagnosis excluded. The history and physical exam play an important role. If a therapeutic decision cannot confidently be made on clinical grounds alone, a diagnostic test may confirm or exclude a diagnosis or clearly indicate the need for further testing. An inappropriately chosen test or misinterpreted test result, however, may mislead the clinician and possibly harm the patient or simply be wasteful. Estimating the predictive values of a diagnostic test will help to avoid these pitfalls. This article shows the clinician a simplified way to do this.

Cessation of unsuccessful pediatric resuscitation--how long is too long?

Emergency teams asked to provide cardiopulmonary resuscitation for pediatric patients often consist of nurses and physicians from various pediatric and nonpediatric specialties. Team members should agree on the timing of termination of unsuccessful resuscitative efforts; however, no firm guidelines about such timing have been established. The purposes of this study were to determine (1) whether a consensus exists among health-care professionals about the optimal duration of unsuccessful resuscitation for pediatric patients and (2) whether attitudes are influenced by individual case prognosis, medical specialty, level of training, or certification in pediatric advanced life support (PALS). By random selection, 140 physicians, nurses, and medical students were asked to specify the duration that they would continue unsuccessful resuscitative efforts for each of two hypothetical cases: one patient with a good prognosis for survival and one with a poor prognosis. Although no clear consensus existed, all groups of health-care providers chose significantly briefer durations of resuscitation for the case with a poorer prognosis (P < 0.01). The specified durations of resuscitation were briefer for those who had PALS certification than for those who did not and for pediatricians than for nonpediatric physicians (P < 0.01). Furthermore, PALS certification (P < 0.01) and pediatric specialty (P < 0.05) contributed as independent variables in influencing the study participants' attitudes about duration of resuscitation, whereas level of training did not. We conclude that no consensus exists among the groups studied on the optimal duration of unsuccessful resuscitative efforts in pediatric patients. We speculate that the opinions might be more uniform if resuscitation of pediatric patients was provided primarily by pediatricians or PALS-certified physicians.

Umbilical morphology: normal values for neonatal periumbilical skin length

Malformations of the umbilicus are a feature of many dysmorphic syndromes including Rieger syndrome, Robinow syndrome, and Aarskog syndrome. The characteristic umbilical malformation in Rieger syndrome consists of redundant periumbilical skin which extends along the cord for an excessive distance. Although the measurement of umbilical skin length plays an important role in the neonatal diagnosis of Rieger syndrome, normal values for this measurement in healthy neonates have not been established. Umbilical skin length was measured in 104 healthy neonates. The length to which the umbilical skin extended along the cranial aspect of cord (mean 11.53 mm, SD 3.58) was significantly longer than the umbilical skin length along the caudal aspect (mean 8.71 mm, SD 2.89) (P less than .05). Multiple regression analysis revealed a significant association between age and umbilical skin length. Birth weight, length, and gestational age were not significantly associated with umbilical skin length when adjusted for the other three variables. No significant differences in umbilical skin length were observed between male and female groups. The above normal values should aid in the neonatal diagnosis of Rieger syndrome, and furthermore it is recommended that cranial umbilical skin length measurement be included in the examination of the dysmorphic child.