Adriana Rodríguez

Differential reactivity of salivary igA and igG against streptococcus mutans proteins in humans with different caries experience

Dental caries is an infectious disease which still constitutes a public health concern. It begins at an early age and is caused mainly Streptococcus mutans (S. mutans). The aim of this study was to characterize the salivary humor immune response to S. mutans proteins in patients with caries, with history of caries and without caries, in order to determine which S. mutans proteins participate in the immunological response in subjects with different caries experience. Saliva was collected by spontaneous salivation for 5 minutes from 60 subjects aged 18 to 30 years, classified according to their caries experience as: without caries (Group I), with active caries (Group II) and with history of caries (Group III). The antigens derived from S. mutans by sonication were recognized by salivary IgA and IgG by Western Blot. The results showed that all the individuals studied recognized S. mutans proteins with molecular weights in the range of 8 to 191 kDa, with similar recognition profiles for salivary IgA and IgG. Subjects without caries recognized the 29 kDa protein, also known as S. mutans Antigen A, via salivary IgA, differing from patients with caries and history of caries, who recognized it via IgG. The protective response against S. mutans is mediated by IgA. To conclude, a differential response to the 29 kDa protein between study individuals may be indicative of resistance to dental caries and may have a protective role in the induction of IgA antibodies against dental caries, as found in the group without caries, in contrast to subjects with active caries and history of caries.

Differences in Systemic and Skin Migrating-Specific CD4+ T Cells in Papular Urticaria by Flea Bite

Background: Papular urticaria by flea bite is a chronic allergic condition in which clinical improvement may occur at the age of 7 years, thus representing a natural model of acquired immunologic tolerance in humans. The aim of this study was to characterize regulatory cells and specific responses to flea antigens of CD4+ T lymphocytes expressing cutaneous migration markers in patients with papular urticaria caused by flea bite and with different disease evolution times. Methods: Cell populations were characterized by flow cytometry in samples from patients and healthy controls. Specific cell stimulation was performed with a complete flea body extract. The Mann-Whitney U test was used for comparisons. Results: Total dendritic cells were lower in patients than in healthy controls. No quantitative differences were found in CD4 regulatory T cells. CD4+ T cells from patients produced more IL-4, lL-10, IL-17, and IFN-γ. Patients who experienced the onset of symptoms within the first 5 years of age showed a greater percentage of local (cutaneous lymphocyte antigen +) IL-4- and IL-17-producing cells, while patients who experienced the onset of symptoms after the age of 5 years had a higher percentage of systemic (cutaneous lymphocyte antigen –) IL-10-producing cells. Conclusion: Analysis of the cellular immune response against whole flea antigen in patients with papular urticaria by flea bites suggests a possible participation of inflammatory cytokines in the skin reaction (Th17) and a systemic control mechanism (IL-10). This pattern of cytokine production in patients could be a consequence of an impaired dendritic cell population.

Differences in IgE mediated basophil degranulation induced by proteic fractions from whole flea body extract in patients with papular urticaria by flea bite and healthy controls.

BackgroundPapular urticaria by flea bite (PUFB) is a chronic inflammatory disease in children. The aim of this study was to assess the functional activity of IgE to protein fractions from flea body extract, through basophil degranulation in PUFB patients and controls.MethodsBasophil degranulation, measured by overexpression of CD63 surface molecules, was evaluated by flow cytometry in samples from patients and controls. Cell stimulation was performed with three fractions with different molecular weight from flea body extract using a Basotest® modified protocol. Mann–Whitney U-test was used for comparisons.ResultsSpecific IgE from PUFB patients and healthy controls induced basophil degranulation to flea body extract with no significant differences between them (16.2 ± 3.1% vs 13.6 ± 2.8% p = 0.77). However, when flea extract was analyzed in fractions with proteins ranging different molecular weights, significant differences were observed on the response from patients compared with controls to <50 kD (14.9 ± 5.1% vs 9.7 ± 2.1% p = 0.0058) and 50–100 kD proteic fractions (8.3 ± 3.2% vs 2.8 ± 1.6% p = 0.0021).ConclusionIn this study, was established that the differential response by IgE, in PUFB, depends from the molecular weight of the antigens contained in the flea extract. These antigens may be related to 30–35 kD proteins previously described as major allergens.

Expression of IL-10, IL-4 and IFN-γ in active skin lesions of children with papular urticaria

INTRODUCTION Papular urticaria caused by the bites of fleas traditionally has been defined as a chronic allergic disease. However, currently no clear relationship has been described between this pathology and common allergic diseases. OBJECTIVE The expression of IL-10, IL-4 and IFN-γ as markers of effector T cell responses was examined in skin lesions of patients with papular urticaria by flea bite. MATERIALS AND METHODS Fourteen skin lesion biopsies were sampled from children with a clinical diagnosis of papular urticaria by flea bite and were compared with 5 healthy skin biopsies of children with no history of the disease. All children were under 12 years old. RNA was extracted with trizol and the expression levels of cytokines were analyzed by real time PCR technique. RESULTS A wide range in the expression levels of IFN-γ and IL-10 was noted as well as constant low values of IL-4. Three distinct profiles were observed, but which did not correspond to a recognizable pattern among the patients. The samples obtained from healthy tissues showed no expression of any of the cytokines. CONCLUSIONS This is the first characterization of cytokines that mediate the immune response at the site of the skin lesion in children with papular urticaria by flea bite. The data indicated that the local response was mixed and that a single phenotype is not predominant among the patients.

Primary Mediastinal Pure Seminomatous Germ Cell Tumor (Germinoma) as a Rare Cause of Precocious Puberty in a 9 Year-Old Patient

Less than 5%-7% of germ cell tumors are extragonadal, with the central nervous system being the most common location in children, followed by retroperitoneum and mediastinum. Only 10% of mediastinal tumors are malignant and one-third of these are pure seminomas (germinomas). We report the case of a 9-year-old boy with development of secondary sexual characteristics. Beta-human chorionic gonadotropin was elevated and a mediastinal mass was found. Final histology showed a pure seminomatous germ cell tumor. To our knowledge, this is the first report of a boy with precocious puberty secondary to a mediastinal germinoma.