Further delineation of the KBG syndrome caused by ANKRD11 aberrations

Loss-of-function variants in ANKRD11 were identified as the cause of KBG syndrome, an autosomal dominant syndrome with specific dental, neurobehavioural, craniofacial and skeletal anomalies. We present the largest cohort of KBG syndrome cases confirmed by ANKRD11 variants reported so far, consisting of 20 patients from 13 families. Sixteen patients were molecularly diagnosed by Sanger sequencing of ANKRD11, one familial case and three sporadic patients were diagnosed through whole-exome sequencing and one patient was identified through genomewide array analysis. All patients were evaluated by a clinical geneticist. Detailed orofacial phenotyping, including orthodontic evaluation, intra-oral photographs and orthopantomograms, was performed in 10 patients and revealed besides the hallmark feature of macrodontia of central upper incisors, several additional dental anomalies as oligodontia, talon cusps and macrodontia of other teeth. Three-dimensional (3D) stereophotogrammetry was performed in 14 patients and 3D analysis of patients compared with controls showed consistent facial dysmorphisms comprising a bulbous nasal tip, upturned nose with a broad base and a round or triangular face. Many patients exhibited neurobehavioural problems, such as autism spectrum disorder or hyperactivity. One-third of patients presented with (conductive) hearing loss. Congenital heart defects, velopharyngeal insufficiency and hip anomalies were less frequent. On the basis of our observations, we recommend cardiac assessment in children and regular hearing tests in all individuals with a molecular diagnosis of KBG syndrome. As ANKRD11 is a relatively common gene in which sequence variants have been identified in individuals with neurodevelopmental disorders, it seems an important contributor to the aetiology of both sporadic and familial cases.     

Clonal dysregulation of the antibody response to tetanus-toxoid after bone marrow transplantation

After bone marrow transplantation (BMT), a prolonged dysregulation of humoral immunity can be observed. In the present study, we investigated whether this is reflected in an abnormal production of specific antibodies (Ab) to the T-cell-dependent recall antigen tetanus-toxoid (TT). The study group consisted of children receiving transplants of an unmodified allogeneic graft and of adults receiving either a T-cell- depleted allogeneic or an unmodified autologous BM graft. Findings were compared with those in healthy controls. In pediatric graft recipients, who were routinely revaccinated early after BMT, the Ab response was quantitatively superior to that in adult graft recipients who did not receive early revaccination. In the majority of graft recipients, the time period after vaccination required to reach the peak level of antibodies was prolonged and the number of responding TT-specific B- cell clones was markedly decreased in comparison with controls. In controls, a low frequency of dominant B-cell clones may produce low quantities of homogeneous Ab components (H-Ab) against a heterogeneous background. However, in BM graft recipients, "overshooting" of Ab production by separate B-cell clones was observed, resulting in the development of H-Ab at a relatively high concentration. These abnormalities were present up to 10 years after BMT, irrespective of either the age of the recipient, the modulation of the graft, or the vaccination schedule used. It is hypothesized that the dysregulated Ab production is the consequence of activation of a restricted number of resting memory B cells, present in germinal centers, repopulating gradually after BMT. Our data show that routine revaccination early after BMT improves the humoral immune response. However, because of a clonally dysregulated Ab production, long-lasting qualitative defects may be present even after normalization of Ab titers.     

Antiidiotypic IgG crossreactive with Rh alloantibodies in red cell autoimmunity

IgG autoantibodies eluted from RBCs of antiglobulin positive normal blood donors contained at least two antibody populations, an IgG autoantibody (Ab 1), and an IgG population (Ab 2) that agglutinated RBCs coated with some Rh(D) alloantibodies. Eight of 24 autoantibody eluates tested agglutinated 3 of 10 anti-Rh(D) sensitized RBCs. The agglutinating activity was inhibited specifically by preincubation of the autoantibody eluate with the reactive anti-D. The reaction did not require the Fc domain of the anti-Rh(D), since autoantibody eluates agglutinated RBCs coated with F(ab')2 prepared from the reactive anti-D sera. These findings indicate that the RBCs of some antiglobulin- positive blood donors contain an immunoglobulin auto-antiidiotype (Ab 2) against the RBC autoantibody (Ab 1) which is demonstrable through its cross-reactivity with selected Rh(D) alloantibodies. Identification of auto-antiidiotypes in RBC autoimmunity lends support to the idiotype- antiidiotype network hypothesis of immune regulation and is consistent with the bizarre and complex serology of autoimmune hemolytic anemia. The absence of clinical hemolysis in antiglobulin-positive normal blood donors suggests that immunoglobulin idiotype-antiidiotype interactions may play a role in modulating the effects of RBC autoimmunity.     

Hemostatic plug formation in normal and von Willebrand pigs: the effect of the administration of cryoprecipitate and a monoclonal antibody to Willebrand factor

Hemostatic plug (HP) formation was investigated in the ear bleeding time incision in normal and von Willebrand pigs. HP volume was calculated by integrating the areas of serial sections. In normal pigs (n = 11), platelets immediately formed a layer on the surface of the cut channel. Platelet aggregates formed at the ends of transected vessels and gradually enlarged. Finally, all transected vessels were occluded by HP and bleeding stopped. In contrast, large HPs were formed in the incision in von Willebrand's disease (vWD) pigs (n = 4); these HPs did not cover the ends of the transected vessels, which continued to bleed, allowing the formation of large hemostatically ineffective platelet aggregates in the incision. Canals traversed these HPs, and bleeding from the open vessels may have continued through them. After infusion of cryoprecipitate into a vWD pig, the bleeding time shortened, and the morphological findings of the HPs were similar to those of normal pigs. In normal pigs (n = 3) infused with an anti- Willebrand factor monoclonal antibody, which prolonged the bleeding time, a large HP formed in the incision, similar to that observed in the vWD pig. The volume of the normal and vWD HPs increased with time. These in vivo findings suggest that Willebrand factor is involved in the localization of the HP to the damaged vessel and may also play a role in platelet-platelet interaction. A computerized morphometric technique was used for measuring the volume of the hemostatic plugs and the distance of sequential points on the perimeter of the HP from the center of selected bleeding vessels.     

The major histocompatibility complex region marked by HSP70-1 and HSP70- 2 variants is associated with clozapine-induced agranulocytosis in two different ethnic groups

Genes of the major histocompatibility complex (MHC) have been associated with susceptibility to drug-induced adverse reactions. We previously found that clozapine-induced agranulocytosis (CA) is associated with the HLA-DRB1*0402, DRB4*0101, DQB1*0302, DQA1*0301 haplotype in Ashkenazi Jewish patients and with the HLA-DRB1*1601, DRB5*02, DQB1*0502, DQA1*0102 haplotype in non-Jewish patients. In the present study, we tested the hypothesis that the variants of the heat- shock protein 70 (HSP-70) encoded by the HSP-70 loci located within the MHC region and known to be involved in apoptosis and regulation of cell proliferation could play an important role in molecular mechanisms of CA. First, we analyzed HSP70-2 polymorphism in risk-associated haplotypes from HLA homozygous cells and normal individuals and confirmed that the HSP70-2 9-kb variant was associated invariably with DR4 (HLA-DRB1*0402, DQB1*0302) and DR2 (HLA-DRB1*01601, DQB1*0502, DQA1*0102 and HLA-DRB1*1501, DQB1*0602) haplotypes, which were the haplotypes found increased in Jewish and non-Jewish patients with CA, respectively. The 9.0-kb variant was also found to be associated with HLA-B44, DRB1*0401 and HLA-B44, DRB1*07 haplotypes. Second, in patients with CA (12 Ashkenazi Jewish and 20 non-Jewish patients), HSP70-1 A and HSP70-2 9.0-kb variants were associated with the MHC haplotypes found by us to be markers of susceptibility to CA. The clozapine-treated control group had an excess number of HSP70-1 C and HSP70-2 8.5-kb variants, consistent with genetic resistance to CA associated with those variants. This finding supports our hypothesis that a dominant gene within the MHC region (marked by HSP70-1 and HSP70-2), but not necessarily HLA, is associated with CA in two different ethnic groups.     

Elevated levels of homocysteine predict cardiovascular death, nonfatal myocardial infarction, and symptomatic bypass graft disease at 2-year follow-up following coronary artery bypass surgery

Severe graft disease occurs in patients at a rate of approximately 15% within the first year of coronary artery bypass grafting (CABG). In this study, the authors examined predictors of the combined end point of death, nonfatal myocardial infarction (MI), and bypass graft disease at 2-year follow-up after CABG. One hundred twenty-one consecutive patients were included in this study after informed consent was obtained. In univariate analysis, there was a significantly (P<.05) higher homocysteine level (11.0 ng/mol vs 9.7 ng/mol, P=.04) in patients who met the combined end point vs those who did not. There were no statistically significant differences in the following: low-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and lipoprotein(a) values; age; body mass index; smoking and diabetes status; statin or aspirin use; creatinine level; hematologic markers; left ventricular ejection fraction; number of bypass grafts; and distribution of coronary artery disease. Logistic regression analysis modeling for low-density lipoprotein cholesterol, lipoprotein(a), fibrinogen, and homocysteine showed that homocysteine value (P=.016) was an independent predictor of the primary combined end point.     

A five-drug remission induction regimen with intensive consolidation for adults with acute lymphoblastic leukemia: cancer and leukemia group B study 8811

The goal of this phase II multicenter clinical trial was to evaluate a new intensive chemotherapy program for adults with untreated acute lymphoblastic leukemia (ALL) and to examine prospectively the impact of clinical and biologic characteristics on the outcome. One hundred ninety-seven eligible and evaluable patients (16 to 80 years of age; median, 32 years of age) received cyclophosphamide, daunorubicin, vincristine, prednisone, and L-asparaginase; 167 patients (85%) achieved a complete remission (CR), 13 (7%) had refractory disease, and 17 (9%) died during induction. A higher CR rate was observed in younger patients (94% for those < 30 years old, 85% for those 30 to 59 years old, and 39% for those > or = 60 years old, P < .001) and in those who had a mediastinal mass (100%) or blasts with a T-cell immunophenotype. Eighty percent of B-lineage and 97% of T-cell ALL patients achieved a CR (P = .01). The coexpression of myeloid antigens did not affect the response rate or duration. Seventy percent of those with cytogenetic or molecular evidence of the Philadelphia (Ph) chromosome and 84% of those without such evidence achieved a CR (P = .11). Patients in remission received multiagent consolidation treatment, central nervous system prophylaxis, late intensification, and maintenance chemotherapy for a total of 24 months. After a median follow-up time of 43 months, the median survival for all 197 patients is 36 months; the median remission duration for the 167 CR patients is 29 months. Favorable pretreatment characteristics relative to remission duration or survival are younger age, the presence of a mediastinal mass or lymphadenopathy, a white blood cell count (WBC) less than 30,000/microL, L1 morphology, T or TMy immunophenotype, and the absence of the Ph chromosome. The estimates of the proportion surviving at 3 years are 69% for patients less than 30 years old, 39% for those 30 to 59 years old, 89% for those who had a mediastinal mass, 59% with WBC less than 30,000/microL, 63% with L1 morphology, 69% for T or TMy antigen expression, and 62% for those who lack the Ph chromosome. Fifteen patients (8%) had no unfavorable prognostic factors and have an estimated probability of survival at 5 years of 100% (95% confidence interval, 77% to 100%). This intensive chemotherapy regimen produces a high remission rate and a high proportion of durable remissions in adults with ALL.     

High-dose intravenous gammaglobulin in alloimmunized platelet transfusion recipients

High-dose intravenous gammaglobulin (polyvalent immunoglobulin G) has been shown to be of benefit in some patients with immune thrombocytopenic purpura (ITP), possibly by producing reticuloendothelial system blockade. We studied this approach in patients refractory to random donor platelet transfusion using an IV IgG preparation manufactured by the Swiss Red Cross. Eleven adult patients with acute leukemia received either 0.4 g IgG/kg/d intravenously X five days (four patients) or 0.6 g/kg/d X five days (seven patients). All patients had high levels of lymphocytotoxic antibody and poor responses to random donor platelets. Except for mild headaches in two patients, there were no side effects related to the IgG infusions. All patients had significant elevations of serum IgG on the day after completion of treatment. Either random donor or partially HLA-matched platelet transfusions were administered the day after and, in some cases, during the IgG therapy. No patient had an improvement in one hour posttransfusion platelet count increments. Two additional patients received pooled platelet concentrates incubated for 30 minutes at 37 degrees C with IgG at a final concentration of 3 g% prior to transfusions. These results indicate that high-dose IgG, an extremely expensive treatment, cannot be recommended for alloimmunized adults with leukemia.