The KMT2A recombinome of acute leukemias in 2023.

Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2A gene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2A gene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5'-KMT2A, two patients had a 5'-KMT2A deletion, and one ETV6::RUNX1 patient had an KMT2A insertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2A recombinome in acute leukemia patients. Besides the scientific gain of information, genomic breakpoint sequences of these patients were used to monitor minimal residual disease (MRD). Thus, this work may be directly translated from the bench to the bedside of patients and meet the clinical needs to improve patient survival.

The MLL recombinome of acute leukemias in 2017.

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients.

The MLL recombinome of acute leukemias in 2013.

Chromosomal rearrangements of the human MLL (mixed lineage leukemia) gene are associated with high-risk infant, pediatric, adult and therapy-induced acute leukemias. We used long-distance inverse-polymerase chain reaction to characterize the chromosomal rearrangement of individual acute leukemia patients. We present data of the molecular characterization of 1590 MLL-rearranged biopsy samples obtained from acute leukemia patients. The precise localization of genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and novel TPGs identified. All patients were classified according to their gender (852 females and 745 males), age at diagnosis (558 infant, 416 pediatric and 616 adult leukemia patients) and other clinical criteria. Combined data of our study and recently published data revealed a total of 121 different MLL rearrangements, of which 79 TPGs are now characterized at the molecular level. However, only seven rearrangements seem to be predominantly associated with illegitimate recombinations of the MLL gene (≈ 90%): AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, ELL, partial tandem duplications (MLL PTDs) and MLLT4/AF6, respectively. The MLL breakpoint distributions for all clinical relevant subtypes (gender, disease type, age at diagnosis, reciprocal, complex and therapy-induced translocations) are presented. Finally, we present the extending network of reciprocal MLL fusions deriving from complex rearrangements.

An unusual cytogenetic rearrangement originating from two different abnormalities in chromosome 6 in a child with acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is usually associated with a favorable outcome, but about 10% of patients tend to relapse. The genetic hallmark of APL is a balanced translocation involving chromosomes 15 and 17, and the PML-RARa gene fusion is found in more than 90% of these cases. Other chromosomal abnormalities are commonly found in APL, but their clinical significance has yet to be determined. Here we report a case of childhood APL that was studied by conventional cytogenetics along with molecular cytogenetic techniques. The patient showed a complex karyotype with an unusual cytogenetic rearrangement originating from two different abnormalities in a single chromosome 6. Our case is an exceptional example of a cryptic cytogenetic anomaly in APL and underscores the importance of detailed genetic characterization.

Avaliação fisiológica e comportamental de cães utilizados em terapia assistida por animais (TAA) / Phyisiological and behavioral assessment in dogs used in Animal-Assisted Therapy (AAT)

Realizou-se a observação comportamental de nove cães terapeutas (oito da raça Labrador Retriever e um Golden Retriever), dosaram-se cortisol sérico e salivar, aferiram-se a temperatura retal, a pressão arterial sistólica e as frequências cardíaca e respiratória nos seguintes momentos: M0 (média de três avaliações do cão em repouso) e em M1, M2 e M3 (imediatamente antes, imediatamente após e decorridas 24h das atividades de terapia assistida por animais - TAA), respectivamente. Não houve diferença significativa quanto às características estudadas (P>0,05), exceto pela temperatura, que foi mais elevada em M1 e M2 do que em M0 (P=0,009). A avaliação comportamental, realizada de maneira descritiva, não apresentou alteração negativa. Houve diferença significativa quanto à concentração de cortisol sérico entre os momentos M1 e M3 (P=0,071), e não ocorreu diferença da concentração do cortisol salivar entre os quatro momentos (P=0,746). As alterações observadas foram atribuídas à contenção e à manipulação dos animais e não desencadearam desconforto físico ou estresse dignos de nota em cães.

Behavioral observation of nine therapist dogs (eight Labrador Retrievers and one Golden Retriever) was performed and serum and salivar cortisol dosage, rectal temperature, systolic blood pressure and heart and respiratory rates were measured and evaluated at the following moments: M0 (average of three evaluations of the dog at rest) and M1, M2 e M3 (immediately before, at the end and 24 hours after the AAT activities, respectively). There was no significant difference in the parameters between the moments (P>0.05) except for temperature, which was higher in M1 and M2 than M0 (P=0.009). The behavioral assessment was conducted in a descriptive way and didn't present a negative effect. There was significant difference when comparing the serum cortisol levels between M1 and M3 (P=0.0712). There wasn't asignificant difference in salivary cortisol levels when comparing the values of the four moments (P=0.7458). The observed alterations are probably related to the containment and handling of animals, demonstrating that the therapy doesn't have a negative effect on dogs.

Identification of a de novo inv dup(X)(pter--> q22) by multicolor banding in a girl with Turner syndrome.

We report on a 23-year-old girl with short stature, short and wide neck, low posterior hairline, hypogonadism, underdeveloped breasts, infantile uterus, ovaries not visualized, and primary amenorrhea. Cytogenetic G-banding analysis revealed a mosaic karyotype of 46,X,dup(X)(q22)[35]/45,X[15], confirming the clinical suspicion of Turner syndrome. Molecular cytogenetics using a multicolor banding probe set for the X-chromosome characterized an inverted dup(X). The karyotype of the patient was therefore interpreted as 46,X,inv dup(X) (pter --> q22::q22 --> pter). This patient had a mosaic Turner syndrome with a cell line comprising partial trisomy Xpter to Xq22 and partial monosomy Xq22 to Xqter.

An in vitro model to study the effect of antibodies and cell receptor analogues on meningococcal adhrence to human oroepithelial cells

We have investigated different experimental schedules to achieve adherence of Neisseria meningitidis group B to cultured and buccal epithelial cells (BEC) and the effect of antibodies and receptor analogues on bacterial adherence. No adherence of meningococcus was observed when HeLa, HEp-2 or KB cells were used, but high rates of adherence to BEC occurred. The effect of antibodies on bacterial adherence was studied in assays carried out in the presence of saliva and serum collected from convalescing children with meningococcal meningitis and children vaccinated with VAMENGOC B-C. Both saliva and serum from the convalescent patients inhibited the adherence of meningococci, but saliva and serum from vaccinated children did not, corroborating our previous data of a poor antibody response induced by this vaccine. Human colostrum did not affect meningococcal adherence despite the presence of antibodies to N. meningitidis detected by ELISA. Inhibition of adherence by sera from an immunized horse, rabbits and mice, as well as by cell receptor analogues (outer-membrane complex and purified polysaccharide C), was observed. Our results show that up to now BEC continue to be the best cells to study meningococcal adherence and the effect of adherence inhibitors.

Estudos cromossômicos em indivíduos portadores de retardo mental e atraso psicomotor / Chromosomal investigation in mentally handicapped and psychomotor retardation patients

O retardo mental é uma característica comum aos pacientes que buscam o Serviço de Genética Médica, apresentando heterogeneidade clínica e etiológica. Neste trabalho, estudos cromossômicos foram realizados em 30 indivíduos portadores de retardo mental e atraso psicomotor. Verificamos que 40 por cento dos indivíduos investigados apresentaram anomalias cromossômicas. Nos demais casos (60 por cento) o cariótipo foi normal. Este estudo reforça a importância da investigaçåo citogenética em indivíduos portadores de retardo mental e atraso psicomotor rastreando aberraçöes cromosssômicas numéricas ou estruturais e auxiliando no diagnóstico, prognóstico e aconselhamento gewnético das famílias

Estudos cromossomicos em individuos portadores de retardo mental e atraso psicomotor

O retardo mental e uma caracteristica comum aos pacientes que buscam o Servico de Genetica Medica, apresentando heterogeneidade clinica e etiologica. Neste trabalho, estudos cromossomicos foram realizados em 30 individuos portadores de retardo mental e atraso psicomotor: Verificamos que 40 por cento dos individuos investigados apresentaram anomalias cromossomicas. Nos demais casos (60 por cento) o cariotipo foi normal. Este estudo reforca a importancia da investigacao citogenetica em individuos portadores de retardo mental e atraso psicomotor rastreando aberracoes cromossomicas numericas ou estruturais e auxiliando no diagnostico e Aconselhamento Genetico das familias.

Inhibition of enteropathogenic Escherichia coli adhesion to HeLa cells by serum of infants with diarrhea and by cord serum

We have studied the effect of serum from infants with diarrhea and of cord serum on the localized adherence of enteropathogenic Escherichia coli (EPEC) to HeLa cells. Serum samples from 16 infants with diarrhea due to EPEC of serotypes O55:H6, O111: H-, O111:H2, O119:H6 and O142:H6 were used. The adherence ability of EPEC strains belonging to serotypes identical to (homologous) or different from (heterologous) those isolated from the infants' feces was highly inhibited by samples of infant serum collected both during the acute phase of the illness and upon discharge from the hospital. These data confirm the development of antibodies against EPEC adhesins and the cross-reaction between different EPEC serotypes. Cord serum inhibited the localized adherence of EPEC strains at different levels according to the serotype of the strain studied. These results suggest that the placental transfer of adhesin-related antibodies does not protect the newborn against EPEC infections, since half of our patients were less than 30 days old

Inhibition of enteropathogenic Escherichia coli adherence to Hela cells by immune rabbit sera

We have studied the effect of immune rabbit sera on the localized (LA) and diffuse (DA) adherence to Hela cells of 10 enteropathogenic Escherichia coli (EPEC) strains belonging to serogroups 055, 086, 0111, 0119, and 0142. Anti-La1 serum, obtained by rabbit immunization with an E. coli strain harboring a cloned DNA fragment from an EPEC LA plasmid, strongly inhibited the adherence of all serogroups but one (0142). Similar results were obtained with anti-LA2 serum, which is anti-0111 serum absorbed with a non-adherence 0111:H-EPEC strain. In contrast, non-absorbed anti-055 and anti-0111 sera showed an inhibitory effect mainly on the adherence of homologous strains. Except for one experiment diffuse adherence was not inhibited by any antiserum used. The inhibitory effect of immune sera on localized adhere3nce does not seem to be correlated with plasmid curing sinceadherence plasmid pMS49 proved to be stable a after treatment with anti-055 and anti-0111 sera. The cross-inhibition of adherence by anti-LA sera suggests that localized adherence-related adhesions of the 0.55, 0.86, 0111, and 0119 strains share similar antigens

Stability and expression of enteropathogenic Escherichia coli adherence plasmid pMS49 in the presence of human colostrum

Adhesion of enteropathogenic Escherichia coli (EPEC) to HeLa cells is inhibited by human colostrum. In the present study we investigated the effect of colostrum on the stability of pMS49, an EPEC adherence plasmid coding for localized adhesion and ampicillin (Ap) resistance. The plasmid was highly stable after serial passage of bacterial cultures in Tryptic Soy Broth containing 67%, 50%, 10% (v/v) or no human colostrum. A few variants (0.4%) with a low adherence were observed regardless of the treatment given. Human colostrum did not enhance their emergence. No bactericidal or bacteriostatic effect of colostrum was observed under the experimental conditions used. A specific process regulating plasmid expression is supposed to occur in EPRC strains, giving rise to variants with a lower concentration of the outher-membrane adherence-related protein and consequently lower adherence ability. This process seems to also occur for Ap-resistance genes coded in the same plasmid