Case report: A familial B-acute lymphoblastic leukemia associated with a new germline pathogenic variant in PAX5. The first report in Mexico.

B-cell acute lymphoblastic leukemia (B-ALL) is one of the most common childhood cancers worldwide. Although most cases are sporadic, some familial forms, inherited as autosomal dominant traits with incomplete penetrance, have been described over the last few years. Germline pathogenic variants in transcription factors such as PAX5, IKZF1, and ETV6 have been identified as causal in familial forms. The proband was a 7-year-old Mexican girl diagnosed with high-risk B-ALL at five years and 11 months of age. Family history showed that the proband's mother had high-risk B-ALL at 16 months of age. She received chemotherapy and was discharged at nine years of age without any evidence of recurrence of leukemia. The proband's father was outside the family nucleus, but no history of leukemia or cancer was present up to the last contact with the mother. We performed exome sequencing on the proband and the proband's mother and identified the PAX5 variant NM_016734.3:c.963del: p.(Ala322LeufsTer11), located in the transactivation domain of the PAX5 protein. The variant was classified as probably pathogenic according to the ACMG criteria. To the best of our knowledge, this is the first Mexican family with an inherited increased risk of childhood B-ALL caused by a novel germline pathogenic variant of PAX5. Identifying individuals with a hereditary predisposition to cancer is essential for modern oncological practice. Individuals at high risk of leukemia would benefit from hematopoietic stem cell transplantation, but family members carrying the pathogenic variant should be excluded as hematopoietic stem cell donors.

[Inflammatory indexes during remission induction of pediatric acute leukemia]. / Índices inflamatorios durante la inducción a la remisión de leucemia aguda pediátrica.

Background: Inflammatory indexes can reflect the severity of serious diseases such as acute leukemia (AL), which is why they can predict mortality. Objective: To evaluate the prognostic value of mortality of inflammatory indexes during the remission induction stage in patients with pediatric AL. Material and methods: Observational, longitudinal, analytical and retrolective study. Patients aged 0 to 17 years, with a recent and confirmed diagnosis of AL, who had basal (at diagnosis, before the start of treatment) and final (at the end of remission induction, or, in the cases of death, during the period prior to this outcome) complete blood count were included. Results: We included 78 patients, 67 with acute lymphoblastic leukemia (ALL), and 11 with acute myeloblastic leukemia (AML), with 11 and 2 deaths, respectively. Regarding ALL, no index showed significant cut-off points to distinguish deaths. Concerning AML, the indices whose cut-off points distinguished the patients who died in the basal measurement, were the monocyte-lymphocyte ratio (MLR) ≥ 3.11 (sensitivity [Se] 100%, specificity [Sp] 66.67%, AUC 0.8333, p 0.03), and, at the final measurement, the neutrophil-lymphocyte ratio (NLR) ≥ 1.30 and MLR ≥ 0.57 (both with Se 100% and Sp 88.89%, AUC 1.0, p < 0.00001) and systemic immune index (SII) ≥ 246612 (Se 100%, Sp 88.89%, AUC 0.9444, p < 0.0001). With bivariate analysis, only the latter demonstrated an increase in the risk of mortality (p = 0.02). Conclusions: The basal MLR and the final NLR, MLR and SII are prognostic inflammatory indices of mortality in patients with AML undergoing remission induction.

Introducción: los índices inflamatorios pueden reflejar la severidad de padecimientos graves como la leucemia aguda (LA), con lo que pueden predecir la mortalidad. Objetivo: evaluar el valor pronóstico de mortalidad de los índices inflamatorios durante la etapa de inducción a la remisión en pacientes con LA pediátrica. Material y métodos: estudio observacional, longitudinal, analítico y retrolectivo. Se incluyeron pacientes de 0 a 17 años, con diagnóstico reciente y confirmado de LA, que contaron con citometría hemática basal (al diagnóstico, antes del inicio de tratamiento) y final (al término de la inducción a la remisión o en los casos de defunción, en el periodo previo a este desenlace). Resultados: incluimos 78 pacientes, 67 con leucemia linfoblástica aguda (LLA) y 11 con leucemia mieloblástica aguda (LMA), con 11 y 2 defunciones, respectivamente. En la LLA ningún índice mostró puntos de corte significativos para distinguir muertes. En la LMA, los índices cuyos puntos de corte distinguieron a los pacientes que fallecieron en la medición basal fueron el índice monocito linfocito (IML) ≥ 3.11 (sensibilidad [S] 100%, especificidad [E] 66.67%, AUC 0.8333, p 0.03) y en la medición final, el índice neutrófilo linfocito (INL) ≥ 1.30 y el IML ≥ 0.57 (ambos con S 100% y E 88.89%, AUC 1.0, p < 0.00001) y el índice inmunosistémico (IIS) ≥ 246612 (S 100%, E 88.89%, AUC 0.9444, p < 0.0001). Con análisis bivariado solo este último mostró incremento del riesgo de mortalidad (p = 0.02). Conclusiones: el IML basal y el INL, IML e IIS finales son índices inflamatorios pronósticos de mortalidad en pacientes con LMA en inducción a la remisión.

Infections and risk factors for infection-related mortality after pediatric allogeneic hematopoietic stem cell transplantation in Mexico: A single center retrospective study.

OBJECTIVE: To identify the type of infections and risk factors for infection-related mortality (IRM) after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: Retrospective cohort study of patients <16 years of age treated in 2010-2019 was conducted. Unadjusted hazard ratios (HR) and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CIs) were estimated using Cox regression. Cumulative incidence was calculated. RESULTS: Data for 99 pediatric patients were analyzed. The myeloablative conditioning was the most used regimen (78.8%) and the hematopoietic stem cell source was predominantly peripheral blood (80.8%). Primary graft failure occurred in 19.2% of patients. Frequency of acute graft-versus-host disease was 46.5%. Total of 136 infectious events was recorded, the most common of which were bacterial (76.4%) followed by viral infection (15.5%) and then fungal infection (8.1%). The best predictors for infection subtypes where the following: a) for bacterial infection (the age groups of 10.1-15 years: aHR = 3.33; 95% CI: 1.62-6.85 and. >15 years: aHR = 3.34; 95% CI: 1.18-9.45); b) for viral infection (graft versus host disease: aHR = 5.36; 95% CI: 1.62-17.68), however, for fungal infection statistically significant predictors were not identified. Related mortality was 30% (n = 12). Increased risk for infection-related mortality was observed in patients with unrelated donor and umbilical cord stem cells recipients (HR = 3.12; 95% CI: 1.00-9.85). CONCLUSIONS: Frequencies of infections and infection-related mortality appear to be similar to those reported. Unrelated donors and stem cells from umbilical cord recipients were associated with a high risk of mortality.

Analysis of a Novel Mexican Variant of the HBB Gene Associated with ß-Thalassemia Using Bioinformatic Tools.

We present a study performed on 54 unrelated subjects, with and without thalassemic features. Two primer pairs were proposed to perform Sanger sequencing of the complete HBB gene. The bioinformatic analysis was performed taking advantage of the availability of free online tools. In the sample, we found 11 variants, 10 reported, and one novel. Among the variants found, six are clinically important: three encode a premature stop codon [codon 39 (C>T) (HBB: c.118C>T); IVS-II-1 (G>A) (HBB: c.315+1G>A), and one not reported], a double substitution within the same allele [Hb Borås (HBB: c.266T>G) and Hb Santa Giusta Sardegna (HBB: c.282T>C)], and one whose pathogenicity is not yet defined [Hb Fannin-Lubbock I (HBB: c.359G>A)]. Even though the variants Hb Borås and Hb Santa Giusta Sardegna have been described, there is no report of their combined occurrence on the same allele, which could cause hemolytic anemia. Although the p.Leu88Arg and p.Cys93Trp variants do not alter the final length of the protein, the bioinformatic results suggest that there are differences in the tertiary structure of ß-globin genes, mainly affecting helices E and F, being the motifs of interaction with the heme group. The novel variant is a 4 bp insertion that modifies the open reading frame, changing the last amino acid residue and causing a premature stop codon (HBB: c.291-294insGCAC). The variant was associated with ß-thalassemia (ß-thal). Bioinformatic analysis made it possible to predict the consequences that the new variant of the HBB gene caused on the ß-globin tertiary structure.

Variable Expression of Notch1 and Pax5 in Classical Hodgkin Lymphoma and Infection with Epstein-Barr in Pediatric Patients.

NOTCH1 and PAX5 participate in the proliferation and differentiation of B and T lymphocytes. Their expression can be modified by activation of NOTCH1, induced by the Epstein-Barr (EBV) viral proteins identified as LMP1 and LMP2. To identify whether PAX5, NOTCH1, and EBV latency genes participate in the oncogenic process of pediatric patients with classical Hodgkin lymphoma (cHL), the present study aimed to identify the variable expression of NOTCH1 among disease subtypes and to assess its effect on PAX5 expression. A total of 41 paraffin-embedded tissues from Mexican pediatric patients with cHL were analyzed. The expression of CD30, CD20, NOTCH1, PAX5, and LMP1 was evaluated by immunohistochemistry and immunofluorescence. EBV detection was performed by in situ hybridization. Out of all cases, 78% (32/41) of the cHL cases were EBV positive. NOTCH1 expression was detected in 78.1% (25/32) of EBV-positive cases, nodular sclerosis being the most frequent subtype (11/25, 44%). In cases where the expression of both genes was identified, double immunofluorescence assays were conducted, finding no colocalization. We found that Reed-Sternberg cells had aberrant expression compared to their cells of origin (B lymphocytes) due to the molecular mechanisms involved in the loss of expression of PAX5 and that the identification of NOTCH1 could be considered as a candidate diagnostic/prognostic marker and a therapeutic target in pediatric cHL.

[Molecular identification of Hemoglobin D Punjab in cases detected in two families]. / Identificación molecular de la hemoglobina D Punjab en dos familias.

BACKGROUND: Hemoglobin D Punjab is the world most common variant hemoglobin D; in Mexico there are reports of isolated cases. Our goal is to present the clinical and molecular study in two families with HbD Punjab. The objective was to submit molecular diagnosis of two families with Hb D Punjab and clinical features. CLINICAL CASE: Family 1: neonate with maternal history of HbS carrier. Father and sister with natural variants for the evaluated mutations, mother, brother and index case were heterozygous for HbD Punjab. Family 2: neonate with positive neonatal screening for detection of abnormal hemoglobins. Mother and index case were heterozygous for HbD Punjab, homozygous for HFE H63D, and Gilbert's syndrome UGT1A1*28 heterozygous. Father heterozygous for HFE H63D and sister homozygous for such mutation. The study of two families for HbD Punjab, HbS, ß-thalassemia, HFE and Gilbert syndrome was performed by real time PCR. CONCLUSION: The molecular identification of HbD Punjab is an accessible methodological proposal that can adequately distinguish carriers subjects; through this method two additional cases, one initially identified as HbS.

Introducción: la hemoglobina D Punjab (HbD Punjab) es la variante mundial más frecuente de hemoglobina D. En México se tienen reportes de casos aislados. El objetivo es presentar el diagnóstico molecular de dos familias con HbD Punjab y sus características clínicas. Casos clínicos: familia 1: neonato cuya madre era portadora de HbS. El padre y la hermana tenían variante natural para las mutaciones evaluadas, madre, hermano y caso índice heterocigotos para HbD Punjab. Familia 2: neonato con tamiz neonatal positivo para la detección de hemoglobinas anormales. Madre y caso índice fueron heterocigotos para HbD Punjab, homocigotos para HFE H63, y heterocigotos para síndrome de Gilbert UGT1A1*28. Padre, heterocigoto para HFE H63D, y hermana homocigoto para dicha mutación. El estudio de las dos familias para HbD Punjab, HbS, beta-talasemia, HFE y síndrome de Gilbert se hizo mediante PCR en tiempo real. Conclusión: la identificación molecular de la HbD Punjab es una propuesta metodológica accesible y permite diferenciar adecuadamente a los portadores. A través de esta metodología se identificaron dos casos adicionales en nuestro país, uno de ellos identificado inicialmente como HbS.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: response to HLH-04 treatment protocol / Linfohistiocitosis hemofagocítica asociada con el virus de Epstein-Barr: respuesta al tratamiento con el protocolo HLH-04

Abstract Introduction: Hemophagocytic syndrome, macrophage activation syndrome, reactive histiocytosis or hemophagocytic lymphohistiocytosis (HLH) represent a group of diseases whose common thread is reactive or neoplastic mononuclear phagocytic system cells and dendritic cell proliferation. Clinical case: We present a case of an HLH probably associated with Epstein-Barr virus (EBV) in a 4-year-old male patient treated with HLH-04 protocol. Viral etiology in HLH is well accepted. In this case, clinical picture of HLH was assumed secondary to EBV infection because IgM serology at the time of clinical presentation was the only positive factor in the viral panel. Conclusions: Diagnosis of HLH is the critical first step to successful treatment. The earlier it is identified, the less the tissue damage and reduced risk of multiple organ failure, which favors treatment response.

Resumen Introducción: El síndrome hemofagocítico, síndrome de activación de macrófagos, histiocitosis reactiva o linfohistiocitosis hemofagocítica (HLH) representan un grupo de enfermedades cuyo factor común es la proliferación reactiva o neoplásica de las células mononucleares fagocíticas y del sistema de células dendríticas. Caso clínico: Se presenta un caso de HLH sugestivo de tener una asociación con el virus del Epstein Barr (VEB) de un paciente masculino de 4 años de edad, tratado con el protocolo HLH-04. La etiología viral en HLH es reconocida. En este caso se asumió un cuadro de HLH secundario a una infección por VEB, ya que la serología de IgM en el momento de la presentación clínica fue la única positiva en el panel viral. Conclusiones: El diagnóstico de la HLH es el primer paso crítico para el éxito del tratamiento. Entre más temprano se identifique, existe menor daño tisular y menor riesgo de falla orgánica múltiple, lo que favorece la respuesta al tratamiento.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: response to HLH-04 treatment protocol.

INTRODUCTION: Hemophagocytic syndrome, macrophage activation syndrome, reactive histiocytosis or hemophagocytic lymphohistiocytosis (HLH) represent a group of diseases whose common thread is reactive or neoplastic mononuclear phagocytic system cells and dendritic cell proliferation. CLINICAL CASE: We present a case of an HLH probably associated with Epstein-Barr virus (EBV) in a 4-year-old male patient treated with HLH-04 protocol. Viral etiology in HLH is well accepted. In this case, clinical picture of HLH was assumed secondary to EBV infection because IgM serology at the time of clinical presentation was the only positive factor in the viral panel. CONCLUSIONS: Diagnosis of HLH is the critical first step to successful treatment. The earlier it is identified, the less the tissue damage and reduced risk of multiple organ failure, which favors treatment response.

Survival of Mexican Children with Acute Lymphoblastic Leukaemia under Treatment with the Protocol from the Dana-Farber Cancer Institute 00-01.

Our aim in this paper is to describe the results of treatment of acute lymphoblastic leukaemia (ALL) in Mexican children treated from 2006 to 2010 under the protocol from the Dana-Farber Cancer Institute (DFCI) 00-01. The children were younger than 16 years of age and had a diagnosis of ALL de novo. The patients were classified as standard risk if they were 1-9.9 years old and had a leucocyte count <50 × 10(9)/L, precursor B cell immunophenotype, no mediastinal mass, CSF free of blasts, and a good response to prednisone. The rest of the patients were defined as high risk. Of a total of 302 children, 51.7% were at high risk. The global survival rate was 63.9%, and the event-free survival rate was 52.3% after an average follow-up of 3.9 years. The percentages of patients who died were 7% on induction and 14.2% in complete remission; death was associated mainly with infection (21.5%). The relapse rate was 26.2%. The main factor associated with the occurrence of an event was a leucocyte count >100 × 10(9)/L. The poor outcomes were associated with toxic death during induction, complete remission, and relapse. These factors remain the main obstacles to the success of this treatment in our population.