Neonatal screening for severe combined immunodeficiency in Brazil

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• 作者：Marilia Pyles Patto Kanegae^a ; Lucila Akune Barreiros^a ; Juliana Themudo Lessa Mazzucchelli^b ; Sonia Marchezi Hadachi^c ; Laura Maria de Figueiredo Ferreira Guilhoto^c ; Ana Lú ; cia Acquesta^d ; Isabel Rugue Genov^b ; ^e ; Silvia Maia Holanda^f ; Regina Sumiko Watanabe Di Gesu^g ; Ana Lucia Goulart^b ; Amé ; lia Miyashiro Nunes dos Santos^b ; Newton Bellesi^h ; Beatriz Tavares Costa-Carvalho^b ; Antonio Condino-Neto^a ; ^{condino@icb.usp.br" class="auth_mail" title="E-mail the corresponding author}
• 关键词：SCID ; Neonatal screening ; TRECs ; T lymphocytes ; Combined immunodeficiency ; Primary immunodeficiency
• 刊名：Jornal de Pediatria
• 出版年：2016
• 出版时间：July-August 2016
• 年：2016
• 卷：92
• 期：4
• 页码：374-380
• 全文大小：786 K

文摘

To apply, in Brazil, the T-cell receptor excision circles (TRECs) quantification technique using real-time polymerase chain reaction in newborn screening for severe combined immunodeficiency and assess the feasibility of implementing it on a large scale in Brazil.

Methods

8715 newborn blood samples were collected on filter paper and, after DNA elution, TRECs were quantified by real-time polymerase chain reaction. The cutoff value to determine whether a sample was abnormal was determined by ROC curve analysis, using SSPS.

Results

The concentration of TRECs in 8,682 samples ranged from 2 to 2,181 TRECs/μL of blood, with mean and median of 324 and 259 TRECs/μL, respectively. Forty-nine (0.56%) samples were below the cutoff (30 TRECs/μL) and were reanalyzed. Four (0.05%) samples had abnormal results (between 16 and 29 TRECs/μL). Samples from patients previously identified as having severe combined immunodeficiency or DiGeorge syndrome were used to validate the assay and all of them showed TRECs below the cutoff. Preterm infants had lower levels of TRECs than full-term neonates. The ROC curve showed a cutoff of 26 TRECs/μL, with 100% sensitivity for detecting severe combined immunodeficiency. Using this value, retest and referral rates were 0.43% (37 samples) and 0.03% (3 samples), respectively.

Conclusion

The technique is reliable and can be applied on a large scale after the training of technical teams throughout Brazil.