Partial remission in Brazilian children and adolescents with type 1 diabetes. Association with a haplotype of class II human leukocyte antigen and synthesis of autoantibodies.

OBJECTIVE: Characterization of partial remission using the insulin dose-adjusted HbA1c (IDAA1c) ≤ 9 definition in a multiethnic Brazilian population of children and adolescents with type 1 diabetes (T1D), in addition with the determination of both Class II HLA genotype and autoantibodies. METHODS: We analyzed the prevalence of partial remission in 51 new-onset T1D patients with a median time follow-up of 13 months from diagnosis. For this study, anti-GAD65, anti-IA2 and HLA class II genotyping were considered. RESULTS: Partial remission occurred in 41.2% of T1D patients until 3 months after diagnosis, mainly in those aged 5-15 years. We have demonstrated a significant increase in the haplotypes of class II HLA DRB1*0301-DQB1*0201 in children and adolescents with a partial remission phase of the disease (42.9% vs 21.7% in non-remitters, P = .0291). This haplotype was also associated with the reduction of anti-IA2 antibodies production. Homozygote DRB1*03-DQB1*0201/DRB1*03-DQB1*0201 children had the lowest prevalence of IA-2A antibodies (P = .0402). However, this association does not correlate with the time of the remission phase. CONCLUSION: Although the number of patients studied was reduced, our data suggested that the association between genetics and decrease in antibody production to certain islet auto-antigen may contribute, at least in part, to the remission phase of T1D.

Two novel HLA-DRB1 alleles, DRB1*11:261 and DRB1*13:286 identified by sequencing in Brazilian individuals.

Two novel HLA alleles DRB1*11:261 and DRB1*13:286 have nonsynonymous mutations in exon 2.

A prospective study on the prevalence and risk factors for neonatal thrombocytopenia and platelet alloimmunization among 9332 unselected Brazilian newborns.

BACKGROUND: Neonatal thrombocytopenia (NT) occurs in 0.5 to 0.9% of unselected Caucasian newborns. However, the prevalence of this complication in other populations is unknown. In this study the prevalence/causes of NT was determined in Brazilian newborns, a population characterized by admixture among Indigenous, Africans, and Caucasians. STUDY DESIGN: A prospective study was carried out in a 3-year period, to determine the prevalence and causes of thrombocytopenia in cord blood samples. Genotyping for HPA 1-5 systems was performed in pairs of mother/neonates with and without thrombocytopenia. All mothers with genotypic mismatches from each group were tested for HPA-specific antibody using the MAIPA technique to identify alloimmunization. RESULTS: Platelet counts <100 x 10(9)/L were detected in 1.5% of 9,332 unselected newborns. In 0.15%, platelet count was <50 x 10(9)/L. Clinically significant bleeding was rare. Underlying diseases were present in 48% of the thrombocytopenic cases. HPA 1-5 system genotype mismatches occurred in 50% of gestations, but did not predict the risk for thrombocytopenia. Notably, mismatched genotypes for HPA-5 were slightly increased in the thrombocytopenic group. The presence of anti-HPA-5b antibodies was observed in 0.05% of unselected pregnancies, but increased to 12% among mothers of neonates with thrombocytopenia and mismatched genotype (N = 51). CONCLUSIONS: Neonatal thrombocytopenia is common among Brazilian newborns at rates comparable with those described among Caucasians. These data suggest that screening for genotypic HPA mismatch, followed by an HPA-specific immunoassay system, particularly for the HPA-5 system, among mothers of newborns with thrombocytopenia in our population would allow the identification of pregnancies at risk of alloimmune thrombocytopenia.

Correlation of IL-6 and IL-10 production following bone marrow transplantation with donor cytokine gene polymorphisms / Correlação da produção de IL-6 e IL-10 seguindo o transplante de medula óssea com os polimorfismos de genes de citocinas do doador

Several candidate gene studies have demonstrated that genetic polymorphisms in cytokine genes contribute to variations in the levels of cytokines produced and this variation may influence the occurrence and severity of complications after stem cell transplantation (HSCT). In this work we compared the serum concentrations of TNF-α, IFN-γ, IL-6, IL-10, and TGF-β1 in 13 recipients following HSCT with the TNF-308, IFNG+874, IL6-174, IL10-1082,-819,-592, and TGFB1+869,+915 polymorphisms. Serum cytokine levels were assessed using commercial ELISA kits for TNF-α, IFN-γ, IL-6, IL-10, and TGF-β1 (BioSource®, Nivelles, Belgium, Europe). Donor/recipient genotypes for these cytokine polymorphisms were analyzed by polymerase chain reaction-sequence-specific primer (PCR-SSP) with the Cytokine Genotyping Primers Kit (One Lambda , Canoga Park, CA, USA). We found correlation between the levels of IL-6 and IL-10 concentrations following HSCT and the IL6-174 and IL10-1082,-819,-592 polymorphisms, but not for other cytokines investigated in this study. Those with genotypes associated with low production of IL-6 and IL-10 produced lower levels of these cytokines than those with genotypes associated with high or intermediate production of these cytokines (P < 0.05).

Estudos de vários genes candidatos têm demonstrado que polimorfismos genéticos em genes de citocinas contribuem com variações nos níveis de citocinas produzidas e esta variação pode influenciar a ocorrência e gravidade de complicações após o transplante de células-tronco hematopoéticas (TCTH). Neste trabalho comparamos as concentrações séricas de TNF-α, IFN-γ, IL-6, IL-10 e TGF-β 1 em 13 receptores seguindo o TCTH com os polimorfismos TNF-308, IFNG+874, IL6-174, IL10-1082,-819,-592 e TGFB1+869,+915. Os níveis séricos de citocinas foram medidos usando-se kits comerciais de ELISA para TNF-α, IFN-γ, IL-6, IL-10 e TGF-β 1 (BioSource®, Nivelles, Belgium, Europe). Os genótipos de doadores/receptores para estes polimorfismos de citocinas foram analisados pela reação em cadeia da polimerase com sequências específicas de primer (PCR-SSP) com o kit Cytokine Genotyping Primers (One Lambda, Canoga Park, CA, USA). Encontramos correlação entre os níveis de IL-6 e IL-10 seguindo o TCTH e os polimorfismos IL6-174 e IL10-1082,-819,-592, mas não para outras citocinas investigadas neste estudo. Aqueles com genótipos relativos à baixa produção de IL-6 e IL-10 produziram mais baixos níveis destas citocinas que aqueles com genótipos relativos à produção alta e/ou intermediária destas citocinas (P < 0,05).