Mosaicism in sporadic neurofibromatosis 2 patients

More than half of neurofibromatosis 2 (NF2) patients represent de novo mutations which could have occurred at either pre-zygotic or post- zygotic stages. A post-zygotic mutation can result in mosaicism. In four sporadic NF2 patients, we found NF2 mutations in only a portion of corresponding leukocytes. In two other sporadic patients, no mutations were found in leukocytes but constitutional NF2 mutations were suggested by identical mutations in different tumors from each patient. We screened leukocyte DNA from a total of 16 inherited and 91 sporadic NF2 patients, and found NF2 mutations in 13 (81%) of the former and in 46 (51%) of the latter cases. The 30% difference in the rate of detection of mutations ( P = 0.051) might be partially explained by mosaicism in a portion of sporadic NF2 patients who carry the mutations in such a fashion that their leukocytes are unaffected. Among sporadic cases, we found mutations more frequently in patients with severe phenotypes (59%) than in patients with mild phenotypes (23%) (difference of 36%, P = 0.007). Mosaicism might be more common in the latter patient group since small populations of mutation-bearing cells can in some cases result in mild phenotypes and can also lead to difficulties in identifying mutations. No mutations were found in eight patients suspected of having NF2. Mosaicism with an extremely small population of affected cells may explain the incomplete phenotypes in some of these patients and the lack of mutations in their leukocytes. These findings suggest that mosaicism is relatively common in NF2 and may have important implications for diagnosis, prognosis and genetic counseling.      

Defective co-stimulation and impaired Th1 development in tumor necrosis factor/lymphotoxin-alpha double-deficient mice infected with Candida albicans

To define the immunological functions of tumor necrosis factor (TNF) in Candida albicans infection, TNF/lymphotoxin (LT)-alpha double-deficient mice were assessed for susceptibility to systemic or gastrointestinal infection and parameters of innate and adaptive Th immunity. When compared to wild-type mice, TNF/LT-alpha-deficient mice were more susceptible to either type of infection caused by virulent or low- virulence C. albicans cells. Susceptibility to infection correlated with impaired development of protective Th1 responses, in spite of the production of bioactive IL-12. The occurrence of predominant Th2 responses was associated with both impaired antifungal effector functions of neutrophils and a defective expression of co-stimulatory molecules on macrophages. All functions were improved upon administration of recombinant TNF-alpha, also resulting in increased resistance to infection. These findings indicate that the protective effect of TNF-alpha in candidiasis relies on the induction of antifungal Th1 responses, possibly occurring through stimulation of antifungal effector functions and co-stimulatory activities of phagocytic cells.      

Epileptic spasms without hypsarrhythmia in infancy and childhood: tonic spasms as a seizure type

Epileptic spasms were defined by the International League Against Epilepsy Task Force on Classification and Terminology in 2001 as a specific seizure type. Epileptic spasms without hypsarrhythmia have been described in some series of patients, occurring either in infancy or childhood. More prolonged epileptic spasms without hypsarrhythmia were previously defined as a different seizure type, and referred to as “tonic spasm seizures”. Here, we present a 5‐year‐old boy who started having epileptic spasms without hypsarrhythmia at 8 months of age, effectively treated with oxcarbazepine. With the withdrawal of medication, epileptic spasms returned. Video‐EEG monitoring revealed high‐voltage slow waves superimposed by low‐voltage fast activity, followed by an electrodecremental phase and a burst of asymmetric fast activity, time‐locked to clinical tonic spasm seizures. Brain MRI showed left temporal atrophy with temporal pole grey/white matter junction blurring and ictal PET‐CT showed left basal frontal hypermetabolism. Seizures were refractory to several AEDs and vigabatrin was introduced with seizure cessation. Despite efforts to classify epileptic spasms, these are still considered as part of the group of unknown seizure types. In some cases, a focal origin has been suggested, leading to the term “periodic spasms” and “focal spasms”. In this case, epileptic spasms without hypsarrhythmia, associated with tonic spasms, may be a variant of focal spasms and might be considered as an epileptic syndrome. [Published with video sequence]     

Refining and using Lotus 1-2-3, Part 2. Using Lotus 1-2-3 to assist with indicator monitors

Spreadsheet database tables provide accuracy and flexibility for analysis of indicator monitors and afford substantial time savings. The ease of data rearrangement allows for better detection of patterns, more accurate comparisons against accepted threshold values, and enhances the laboratorian's ability to make recommendations.     

Evaluation of PvuII and XbaI polymorphisms in the estrogen receptor alpha gene (ESR1) in relation to menstrual cycle timing and reproductive parameters in post-menopausal women

Objective: To evaluate the association of −397T>C and −351A>G single nucleotide polymorphisms (SNPs) – also called PvuII and XbaI, respectively – located on estrogen receptor alpha (ERS1) gene with age at menarche, menopause onset, fertility and miscarriage in a population of post-menopausal women. Study design: Cross-sectional study with 273 healthy, high miscegenated, post-menopausal women (mean age of 63.1 ± 9.7 years old). Subjects were genotyped for PvuII and XbaI SNPs by PCR-RFLP and confirmed by automatic sequencing. Reproduction informations (age at menarche, age at menopause, number of pregnancies, fertility rate and miscarriages) were obtained by retrospective study using a questionnaire. Result(s): Age at menarche, menopause onset, number of pregnancies, total fertility rate, and parity did not seem to be influenced by any of the studied genotypes (chi-square, p > 0.05). However, women carrying the xx genotype showed a 44% higher chance of miscarriage, whereas this value did not trespass 16% for any other genotype analyzed. It has been also observed a higher occurrence of miscarriage in association with combined xxpp genotype of ERS1 gene (chi-square, p < 0.01). Conclusion(s): The present data indicate that the studied SNPs on ERS1 gene do not influence the menstrual cycle timing and parity but there is a strong relationship between the xx ERS1 SNP genotype and the incidence of miscarriage in the post-menopausal population analyzed.     

Allogeneic transplantation following a reduced-intensity conditioning regimen in relapsed/refractory peripheral T-cell lymphomas: long-term remissions and response to donor lymphocyte infusions support the role of a graft-versus-lymphoma effect

Rescue chemotherapy or autologous stem cell transplantation (autoSCT) gives disappointing results in relapsed peripheral T-cell lymphomas (PTCLs). We have retrospectively evaluated the long-term outcome of 52 patients receiving allogeneic SCT for relapsed disease. Histologies were PTCL-not-otherwise specified (n=23), anaplastic large-cell lymphoma (n=11), angioimmunoblastic T-cell lymphomas (n=9) and rare subtypes (n=9). Patients were allografted from related siblings (n=33, 64%) or alternative donors (n=13 (25%) from unrelated and 6 (11%) from haploidentical family donors), following reduced-intensity conditioning (RIC) regimens including thiotepa, fludarabine and cyclophosphamide. Most of the patients had chemosensitive disease (n=39, 75%) and 27 (52%) failed a previous autoSCT. At a median follow-up of 67 months, 27 of 52 patients were found to be alive (52%) and 25 (48%) were dead (n=19 disease progression, n=6 non-relapse mortality (NRM)). The cumulative incidence (CI) of NRM was 12% at 5 years. Extensive chronic graft-versus-host disease increased the risk of NRM (33% versus 8%, P=0.04). The CI of relapse was 49% at 5 years, influenced by disease status at the time of allografting (P=0.0009) and treatment lines (P=0.007). Five-year overall survival and progression-free survival (PFS) were 50% (95% CI, 36 - 63%) and 40% (95% CI, 27 - 53%), respectively. The current PFS was 44% (95% CI, 30-57%). In all, 8 out of 12 patients (66%) who received donor-lymphocytes infusions for disease progression had a response. At multivariable analysis, refractory disease and age over 45 years were independent adverse prognostic factors. RIC allogeneic SCT is an effective salvage treatment with a better outcome for younger patients with chemosensitive disease.     

Unequal crossing-over: a common basis of single alpha-globin genes in Asians and American blacks with hemoglobin-H disease

The alpha-globin genes of five black Americans, two Chinese, and five Filipinos with HbH disease (an alpha-thalassemia state in which there is a single functional alpha gene) were analyzed by restriction endonuclease techniques. All subjects were found to have one chromosome 16, lacking both alpha genes, and another containing a single alpha gene (--/-alpha). Restriction endonuclease patterns of the DNA obtained from all 12 subjects were identical and compatible with unequal crossing-over as the mechanism of origin of the single alpha gene in these individuals.     

Hemoglobin E trait reexamined: a cause of microcytosis and erythrocytosis

The current Indochinese resettlement program in the United States has resulted in an increase in the number of persons with hemoglobin E trait. American physicians should be aware of the hematologic expressions of this innocuous condition. The hematologic manifestations of 21 persons with hemoglobin E trait were evaluated. The subjects were of Tai-dam, Vietnamese, Chinese, Laotian, and European origin. These studies showed uniform hematologic manifestations in hemoglobin E trait, characterized by slight microcytosis, by morphologic features resembling those of thalassemia minor, and often by increased erythrocyte count. Hemoglobin instability also was confirmed.     

Antibodies to myeloid precursor cells in autoimmune neutropenia

Antibodies to mature blood neutrophils and to bone marrow myeloid cells have been described in the sera of some patients with apparent autoimmune neutropenia. To further explore the prevalence and specificities of antibodies to myeloid precursor cells, we evaluated sera from 148 patients with suspected autoimmune neutropenia for the presence of antibodies to neutrophils, to cultured myeloid cell lines, and to highly purified bone marrow myeloid progenitor cells. Using an immunofluorescence flow cytometric assay, we identified IgG antibodies in 42 (28%) of these sera that bound specifically to K562 cells, a multilineage cell line originally derived from a patient with chronic myelogenous leukemia. Twenty-two (15%) of the sera also contained IgG antibodies that bound specifically to the primitive myelomonocytic leukemia cell line KG1a. Twenty-five (17%) of the sera had IgG antibodies to myeloid cell lines in the absence of antibodies to mature neutrophils. There was a trend toward more severe neutropenia in patients with antibodies to K562 cells, without antineutrophil antibodies. In further studies, antibodies from 12 sera bound to mononuclear CD34+ cells that had been purified from normal human bone marrow by an immunomagnetic separation procedure. Moreover, two of these sera suppressed the growth of granulocyte-macrophage colony- forming units (CFU-GM) in methylcellulose cultures. The presence of antibodies to primitive hematopoietic cells in the sera of some patients with suspected immune neutropenia suggests that these antibodies may have a role in the pathogenesis of the neutropenia observed.