RESUMO
T cell receptor excision circles (TRECs) and kappa-deleting excision circles (KRECs) are DNA fragments potentially indicative of T and B cell development, respectively. Recent thymic emigrants (RTEs) are a subset of peripheral cells that may also represent thymic function. Here, we investigated TREC/KREC copy numbers by quantitative real-time PCR in the peripheral blood of patients with primary immunodeficiencies (PIDs, n = 145) and that of healthy controls (HCs, n = 86) and assessed the correlation between RTEs and TREC copy numbers. We found that TREC copy numbers were significantly lower in children and adults with PIDs (P < .0001 and P < .002, respectively) as compared with their respective age-matched HCs. A moderate correlation was observed between TREC copies and RTE numbers among children with PID (r = .5114, P < .01), whereas no significant correlation was detected between RTE values and TREC content in the HCs (r = .0205, P = .9208). Additionally, we determined TREC and KREC copy numbers in DNA isolated from the Guthrie cards of 200 newborns and showed that this method is applicable to DNA isolated from both peripheral blood samples and dried blood spots, with the two sample types showing comparable TREC and KREC values. We further showed that RTE values are not always reliable markers of T cell output. Although additional confirmatory studies with larger cohorts are needed, our results provide thresholds for TREC/KREC copy numbers for different age groups.
Assuntos
Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Imunodeficiência Combinada Severa/imunologia , Linfócitos T/imunologia , Adolescente , Adulto , Criança , Pré-Escolar , DNA/genética , DNA/imunologia , Feminino , Hematopoese/genética , Hematopoese/imunologia , Humanos , Lactente , Recém-Nascido , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Triagem Neonatal/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Receptores de Antígenos de Linfócitos T/genética , Imunodeficiência Combinada Severa/genética , Adulto JovemRESUMO
BACKGROUND: Heterozygous relatives of ataxia-telangiectasia (AT) patients are at an increased risk for certain AT-related manifestations. We also show that there is an increase of infection frequency in parents of AT patients. Thus, we hypothesized that the parents might exhibit immune alterations similar to their affected children. METHODS: Lymphocyte phenotyping to enumerate T- and B-cell subsets was performed. Functional analyses included in vitro quantified γ-H2AX, poly (ADP-ribose) polymerase (PARP) and caspase-9 proteins. Chromosomal instability was determined by comet assay. RESULTS: We analyzed 20 AT patients (14F/6M), 31 parents (16F/15M), and 35 age-matched healthy controls. The AT patients' parents exhibited low frequency of naive CD4+ T- (n = 14, 45%) and recent thymic emigrants (n = 11, 35%) in comparison with the age-matched healthy donors. Interestingly, parents with low naive T cells also demonstrated high rate of recurrent infections (9/14, 64%). In comparison with age-matched controls, parents who had recurrent infections and low naive T cells showed significantly higher baseline γ-H2AX levels and H2 O2 -induced DNA damage as well as increased cleaved caspase-9 and PARP proteins. CONCLUSION: Parents of AT patients could present with recurrent infections and display cellular defects that mimic AT patients. The observed immunological changes could be associated with increased DNA double-strand breaks.
Assuntos
Ataxia Telangiectasia , Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Humanos , Pais , Fenótipo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Hyper-IgE syndrome (HIES) patients may share many features observed in severe atopic dermatitis (SAD), making a diagnostic dilemma for physicians. Determining clinical and laboratory markers that distinguish both disorders could provide early diagnosis and treatment. We analyzed patients (DOCK8 deficiency:14, STAT3-HIES:10, SAD:10) with early-onset SAD. Recurrent upper respiratory tract infection and pneumonia were significantly frequent in HIES than SAD patients. Characteristic facial appearance, retained primary teeth, skin abscess, newborn rash, and pneumatocele were more predictable for STAT3-HIES, while mucocutaneous candidiasis and Herpes infection were common in DOCK8 deficiency, which were unusual in SAD group. DOCK8-deficient patients had lower CD3+ and CD4+T cells with a senescent phenotype that unique for this form of HIES. Both DOCK8 deficiency and STAT3-HIES patients exhibited reduced switched memory B cells compared to the SAD patients. These clinical and laboratory markers are helpful to differentiate HIES from SAD patients.
