The Interplay of Cesarean-Section Delivery and First-Birth Order as Risk Factors in Acute Lymphoblastic Leukemia.

BACKGROUND: Childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) has been associated with early-life exposures, including birth by cesarean section (C-section), and a deficit of social exposure (first child). These exposures as proxies for microbiome acquisition in infancy are essential to prime the immune system and restrain later dysregulated immune responses that can trigger ALL in susceptible individuals. We tested risk factors pertaining to immune stimulation that may impact BCP-ALL development. METHODS: Cases comprised 1,126 children (0-12 years) with ALL (BCP-ALL: 78.5%) from the EMiLI study group in Brazil (2002-2020). Age- and sex-matched controls (n = 2,252) were randomly selected from healthy children whose mothers participated in the National Placental and Umbilical Cord Blood Bank donation. Multiple logistic regression was run fitted and adjusted for selected covariates models. RESULTS: C-section delivery was associated with increased risk for ALL [odds ratio (OR) ALL: 1.10; 95% confidence intervals (CI), 1.04-1.15; ORBCP-ALL: 1.09; 95% CI, 1.03-1.14], as well as being the firstborn child. Interaction analysis showed a significant effect of first birth on the observed C-section associations (P < 0.0001). Indeed, high-risk children, namely, firstborn children delivered via C-section were at increased risk for ALL (OR: 2.33; 95% CI, 2.40-4.84) compared with non-first, vaginally born children. An increased risk was found for firstborn children delivered by C-section and non-breastfed with ALL (ORALL: 2.32; 95% CI, 1.27-4.24; ORBCP-ALL: 2.37; 95% CI, 1.18-4.76). CONCLUSIONS: Our observations are in accord with the prediction that exposures determining microbiome composition and adrenal pathway in infancy contribute to the risk of BCP-ALL. IMPACT: These findings encourage the exploration of potential preventive interventions. See related commentary by Wiemels and Gallant, p. 292.

Interaction between birth characteristics and CRHR1, MC2R, NR3C1, GLCCI1 variants in the childhood lymphoblastic leukemia risk.

Background: The incidence rate of childhood acute lymphoblastic leukemia (ALL) differs worldwide, and the interplay between hemostasis actors and the maladaptive responses to environmental exposures has been explored. It has been proposed that endogenous cortisol, induced by different triggers, would eliminate pre-leukemic clones originated in utero. Herein, we tested if the interaction between CRHR1rs242941 C>A, MC2Rrs1893219 A>G, NR3C1rs41423247 G>C, and GLCCI1rs37972 C>T (players in glucocorticoid secretion) and birth characteristics would be associated with ALL risk. Methods: Children aged <10 years were enrolled within the EMiLI project (period: 2012 to 2020). The study had three steps: (1) observational analysis of birth characteristics (n = 533 cases and 1,603 controls); (2) genotyping to identify single-nucleotide variants (n = 756 cases and 431 controls); and (3) case-only to test gene-environment interactions (n = 402 cases). Genetic syndromes were exclusion criteria. The controls were healthy children. The distribution of the variables was assessed through Pearson's chi-square test. Logistic regression (LR) tests were run fitted and adjusted for selected covariate models to estimate the association risk. Formal interaction analysis was also performed. Genotyping was tested by qPCR with TaqMan probes (NR3C1) or by high-resolution melting (MC2R and GLCCI1). Hardy-Weinberg equilibrium (HWE) was accessed by the chi-square test. The genotype-risk association was tested in co-dominant, dominant, and recessive models. The gene-environment interaction odds ratio (iOR) was assessed in case-only. Results: Low birthweight, C-section, and low maternal schooling were associated with increased risk for ALL, adjOR 2.11, 95% CI, 1.02-4.33; adjOR 1.59, 95% CI, 1.16-2.17; and adjOR 3.78, 95% CI, 2.47-5.83, respectively, in a multiple logistic regression model. MC2R rs1893219 A>G was negatively associated with ALL (AG: OR = 0.68; 95% CI = 0.50-0.94 and GG: OR = 0.60; 95% CI = 0.42-0.85), while for GLCCI1 rs37972 C>T, TT was positively associated with ALL (OR = 1.91; 95% CI = 1.21-3.00). The combination of genotypes for MC2R (AA) and GLCCI1 (TT) increased ALL risk (OR = 2.61; 95% CI = 1.16-5.87). In a multiplicative interaction, MC2R rs1893219 A>G was associated with children whose mothers had less than 9 years of schooling (iOR = 1.99; 95% CI = 1.11-1.55). Conclusion: Our study has demonstrated a significant association between MC2R rs1893219 A>G (reduced risk) and GLCCI1 rs37972 C>T variants (increased risk) and childhood ALL susceptibility. Based on this evidence, genes controlling the HPA axis activity may play a role in leukemogenesis, and further investigation is needed to substantiate our findings.

Validation of the single-platform ISHAGE protocol for enumeration of CD34+ hematopoietic stem cells in umbilical cord blood in a Brazilian center

Abstract Background This study aims to validate the single-platform method for enumeration of CD34+ cells, by comparing the performance of two different commercial kits, as well as to evaluate the efficiency of the AccuriTM C6 cytometer in providing direct counts of absolute cell numbers. Method We evaluated 20 samples from umbilical cord blood (UCB), comparing the two different methodologies for enumeration of CD34+ cells: single and dual-platform. For the assessment of the single-platform, Procount and SCE kits were used, both of which use fluorescent beads as a counting reference to obtain absolute CD34+ cells numbers. Moreover, after the acquisition of samples in flow cytometer AccuriTM C6, following the protocol established for each kit, the number of CD34+ cells was recalculated, considering the cell count provided by the AccuriTM C6. Main Results In our analysis, the results showed a strong correlation between the number of CD34+ cells/μL (r2 = 0.77) when comparing the SCE kit and the current dual-platform method. On the other hand, the comparison between Procount kit and dual-platform results showed a moderate correlation for the number of CD34+/μL cells (r2 = 0.64). Conclusion Our results showed that the AccuriTM C6 flow cytometer can be used safely, applying both the dual and single platform analysis strategy. Considering the ISHAGE protocol-based single-platform approach, as the most appropriate methodology for CD34+ cells enumeration, our results demonstrated that the SCE kit has great potential for national standardization of UCB samples analysis methodology.

Celularidade do sangue de cordão umbilical de gestantes hipertensas: estudo caso-controle / Cellularity of the umbilical cord blood of hypertensive pregnant women: a case control study / Celularidad de la sangre de cordón umbilical de gestantes hipertensas: estudio caso-control

OBJETIVO(S): analisar a relação entre celularidade do sangue do cordão umbilical e placentário de gestantes hipertensas e não hipertensas. MÉTODO: estudo caso-controle, com abordagem quantitativa, amostra de 73 gestantes, no período de março a setembro de 2011. Os dados fazem parte do estudo aprovado pelo Comitê de Ética em Pesquisa sob o protocolo de número 126/10. RESULTADOS: foi concluído que 80% das bolsas de sangue de cordão umbilical e placentário coletados de gestantes com hipertensão arterial apresentaram celularidade ≥5 x 108, quantidade adequada no total de células nucleadas, atendendo aos critérios estabelecidos pela Resolução 56. CONCLUSÃO: os resultados contribuíram para a identificação de fatores que possibilitam a obtenção de um quantitativo adequado de células tronco-hematopoiéticas, resultando no aumento do número de transplantes de células tronco-hematopoiéticas no Brasil.

AIM: To analyze the relationship between the cellularity of placental and umbilical cord blood of hypertensive and non-hypertensive pregnant women. METHOD: This is a case-control study that used a quantitative approach. The sample consists of 73 pregnant women and it was conducted from March to September 2011. The data are part of the study approved by the Research Ethics Committee under protocol number 126/10. RESULTS: It was found that 80% of the Umbilical Cord and placental blood bags collected from pregnant women with hypertension presented cellularity ≥5 x 108. This is the appropriate amount in relation to the totality of nucleated cells, given the criteria established by Resolution 56. CONCLUSION: The results contributed to the identification of factors that make it possible to obtain an adequate number of hematopoietic stem cells, resulting in the increased number of hematopoietic stem cell transplantation in Brazil.

OBJETIVO(S): analizar la relación entre celularidad de la sangre del cordón umbilical y placentario de gestantes hipertensas y no hipertensas. MÉTODO: estudio caso-control, con abordaje cuantitativo, muestra de 73 gestantes, en el período de marzo a septiembre de 2011. Los datos hacen parte del estudio aprobado por el Comité de Ética en Investigación bajo el protocolo de número 126/10. RESULTADOS: fue concluido que 80% de las bolsas de sangre de cordón umbilical y placentario colectados de gestantes con hipertensión arterial presentaron celularidad ≥5 x 108, cantidad adecuada en el total de células nucleadas, atendiendo a los criterios establecidos por la Resolución 56. CONCLUSIÓN: los resultados contribuyeron para la identificación de factores que posibilitan la obtención de un cuantitativo adecuado de células madre-hematopoyéticas, resultando en el aumento del número de trasplantes de células madre-hematopoyéticas en Brasil.

PON1 Q192R polymorphism (rs662) is associated with childhood embryonal tumors.

Genetic susceptibility and environment exposures are associated risk factors in carcinogenesis. Gene polymorphisms that decrease the activity of detoxifying carcinogen substances may modify the effect of exposures. We investigated whether the polymorphisms PON1 rs662 (Q192R), and PON1 rs854560 (L55M) would be associated with embryonal tumors in Brazilian children. Blood samples from 163 children with embryonal tumors and 342 as control group were genotyped by TaqMAN real-time PCR assays. Logistic regression was used to evaluate the association between the polymorphisms of cases and controls groups, adjusted by skin color and age strata. When all tumors were taken together, the presence of the PON1 rs662 (Q192R) variant genotype (RR) was associated with an increased risk of developing embryonal tumors (OR = 2.80, 95 % CI 1.12-7.02). The presence of at least one variant PON1 rs662 R allele increased the risk of developing Wilms´ Tumor although without statistical power. However, it was observed a significant association of PON1 rs662 (Q192R) variant genotype (RR) with retinoblastoma (OR = 4.08, 95 % CI 1.13-14.97), whereas the PON1 rs854560 (L55M) polymorphism was not associated with any tumor. These results indicate that PON1 polymorphisms may have an influence on the risk of developing embryonal tumors.