Objective: To validate the quantification of T-cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs) by real-time polymerase chain reaction (qRT-PCR) for newborn screening of primary immunodeficiencies with defects in T and/or B cells in Brazil.Methods: Blood samples from newborns and controls were collected on filter paper. DNA was extracted and TRECs, and KRECs were quantified by a duplex real-time PCR. The cutoff values were determined by receiver operating characteristic curve analysis using SPSS software (IBM®, Armonk, NY, USA).Results: Around 6,881 samples from newborns were collected and TRECs and KRECs were quantified. The TRECs values ranged between 1 and 1,006 TRECs/µL, with mean and median of 160 and 139 TRECs/µL, respectively. Three samples from patients with severe combined immunodeficiency (SCID) showed TRECs below 4/µL and a patient with DiGeorge syndrome showed undetectable TRECs. KRECs values ranged from 10 to 1,097 KRECs/µL, with mean and median of 130 and 108 KRECs/µL. Four patients with agammaglobulinemia had results below 4 KRECs/µL. The cutoff values were 15 TRECs/µL and 14 KRECs/µL and were established according to the receiver operating characteristic curve analysis, with 100% sensitivity for SCID and agammaglobulinemia detection, respectively.Conclusions: Quantification of TRECs and KRECs was able to diagnose children with T- and/or B-cell lymphopenia in our study, which validated the technique in Brazil and enabled us to implement the newborn screening program for SCID and agammaglobulinemia.

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

The rhesus-human reassortant, tetravalent rotavirus vaccine (RRV-TV) was licensed for routine use in the United States of America but it was recently withdrawn from the market because of its possible association with intussusception as an adverse event. The protective efficacy of 3 doses of RRV-TV, in its lower-titer (4 x 10(4) pfu/dose) formulation, was evaluated according to the nutritional status of infants who participated in a phase III trial in Belém, Northern Brazil. A moderate protection conferred by RRV-TV was related to weight-for-age Z-scores (WAZ) greater than -1 only, with rates of 38% (p = 0.04) and 40% (p = 0.04) for all- and- pure rotavirus diarrhoeal cases, respectively. In addition, there was a trend for greater efficacy (43%, p = 0.05) among infants reaching an height-for-age Z-score (HAZ) of > -1. Taking WAZ, HAZ and weight-for-height Z-score (WHZ) indices 0.05) if both placebo and vaccine groups are compared. There was no significant difference if rates of mixed and pure rotavirus diarrhoeal cases are compared in relation to HAZ, WAZ and weight-for-height Z-score (WHZ) indices. Although a low number of malnourished infants could be identified in the present study, our data show some evidence that malnutrition may interfere with the efficacy of rotavirus vaccines in developing countries.

No abstract

Prospective study of rotavirus infections in Belém, Pará, Brazil: clinical and epidemiological features Resumo Um estudo prospectivo acerca das diarréias agudas foi levado a efeito no período de abril de 1990 a setembro de 1992, com o propósito primário de avaliar a imunogenicidade, inocuidade e eficácia de uma candidata a vacina para rotavírus, tetravalente, recombinante símio-humana ("RRV-TV"), envolvendo 540 crianças habitantes de Belém, Pará, Brasil. Considerando que metade desses indivíduos recebeu placebo, tal investigação ensejou a oportunidade de ampliar-se o conhecimento clínico-epidemiológico das infecções por esses agentes na região. Foram registrados 2.789 episódios de diarréia no período acima citado. Desse total, 86 (3,1%) se revelaram associados a rotavírus, com destaque para o sorotipo 1, que concorreu com 67,9% dos casos em que foi possível proceder-se à sorotipagem. Taxas de diarréia por criança/ano de 5,9 e 0,2 foram relacionadas ao total de episódios e os positivos para rotavírus, respectivamente. Aliás, esses agentes foram detectados isoladamente em 70,9% dos 86 casos em que se denotou positividade. Quanto às associações com outros enteropatógenos, prevaleceram os casos em que se identificaram G. intestinalis e E. coli enteropatogênicas, concorrendo com 7,0% e 11,6% das infecções mistas, respectivamente. As taxas mensais de diarréias ocasionadas por rotavírus variaram de 0,8 a 9,6%, com picos de incidência durante os meses mais secos do ano. Valores médios dos escores clínicos de 9,4 e 5,3 foram demonstrados para os casos positivos e negativos para rotavírus, respectivamente.J. pediatr. (Rio). 1994; 70(4):220-225: rotavírus, clínica, epidemiologia.