Biomedical subjects
Publications and source records attributed to C Pignata.
DiGeorge anomaly (DGA) represents a heterogeneous entity, which is often sporadic, although familial cases and the association with monosomy 22q11 have been reported. Recently, a few patients with 10p deletion syndrome and immunological and other laboratory findings similar to DGA have been described. We report on an additional case of partial DGA associated with 10p deletion.
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Seventeen paediatric patients with immunodeficiency syndromes (10 with selective IgA deficiency, four with panhypogammaglobulinaemia, and three with selective T cell deficiency) were investigated for bacterial overgrowth of the small intestine and gut permeability to macromolecules. Five of 12 patients showed viable bacterial counts of more than 2 x 10(5)/ml in jejunal fluid. Bacterial overgrowth was also confirmed indirectly by breath hydrogen determination, which was higher than 10 ppm in four of the five patients with positive jejunal culture. Gut permeability to lactulose and L-rhamnose was abnormal in 16 of the 17 immunodeficient patients, who also had higher mean urinary excretion ratios than control subjects-mean (SD) values were 0.216 (0.160) and 0.029 (0.002), respectively. These studies indicate that bacterial overgrowth of the small intestine is a common feature in immunodeficient patients, regardless of the immunological abnormality. Moreover, these patients have an increased gut permeability to macromolecules.
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The effect of short-term immunosuppressive treatment on the percentage of circulating DR-bearing T cells was investigated in 16 children with HBsAg-positive chronic active hepatitis. DR-positive T cells, thought to represent activated T cells, were significantly increased in all patients as compared to 10 age-matched controls [14.5 +/- 4.2% (mean +/- SD) vs. 0.4 +/- 0.1%, p less than 0.001]. Fifty-six percent of patients showed a decrease in the percentage of DR-positive T cells after 72 h of prednisone therapy. A response did not correlate with the presence of HBeAg, anti-HBeAg, or anti-delta antibodies. There was an inverse relationship (r = -0.56; p less than 0.05) between the decrease of the percent of DR-positive T cells during immunosuppression and pretreatment alanine aminotransferase levels. The persistence of high levels of circulating DR-bearing T cells during therapy may represent the immunological counterpart of more severe disease, and of nonresponsiveness to corticosteroids.
Immunoregulatory cells were enumerated in 19 coeliac disease children on a gluten free diet by means of monoclonal antibodies that define total T lymphocytes (T3), helper/inducer T cells (T4), suppressor/cytotoxic T cells (T8) and monocytes (M1), as well as by means of surface receptors for Fc fragments of IgM and IgG (T mu and T gamma, respectively). In addition, suppressor cell function was assessed in 17 coeliac disease patients by examining the ability of concanavalin-A (Con-A)-activated suppressor cells to inhibit autologous cell response to mitogenic stimulus as compared with age-matched controls. No statistically significant differences were found in the percentages of subsets defined by monoclonal antibodies between coeliac disease patients and age-matched controls, whereas coeliac disease patients had a significant decrease of the subpopulation bearing membrane receptor for Fc fragment of IgG. Mean value was 8.5% in coeliac patients versus 13.4% in age-matched controls. In the functional assay, mononuclear cells from 10 out of 17 coeliac disease patients either totally or partially failed to suppress responder cells after Con-A-activation. This defect is not related to HLA-DR status, because no difference was found between patients-HLA-matched and unmatched normal individuals. In this assay, mononuclear cells of three coeliac disease patients with low suppressor activity were able to inhibit responder cells to the same extent as controls, when indomethacin was used to block prostaglandin production in the induction phase of Con-A-activated suppressor cells. Our results suggest that an abnormality in immunoregulation may play a role in the pathogenesis of coeliac disease.
We report the case of an infant with chronic diarrhea and failure to thrive. Campylobacter jejuni was isolated from stools and treatment with erythromycin resulted in eradication of infection and prompt resolution of symptoms. A 22-month-old girl was referred to our University Hospital because of weight loss and chronic diarrhea, which did not respond to repeated dietetic trials that excluded milk, gluten, and other foodstuffs. Microscopic examination of the jejunal biopsy specimen revealed a mild degree of partial mucosal atrophy with inflammatory infiltrates in the lamina propria without any hallmarks of celiac disease. Repeated stool cultures on Butzler medium were positive for C. jejuni. This finding was associated with a high titer of specific serum antibodies. Erythromycin therapy without any other form of therapy led to prompt improvement, and the patient reached her "own" 50th centile as weight/height ratio. The aim of this report is to alert pediatric gastroenterologists of the possibility that Campylobacter may be associated with chronic diarrhea and failure to thrive.
A sensitive radioimmunoassay for IgG gliadin antibodies is described. Serum specimens were added to wells of plastic microtitre plates coated with gliadin. After removal of the unbound material, gliadin antibodies were detected by adding 125I-labelled staphylococcal protein A (125I-SpA). Serum specimens from coeliac patients on a normal diet or on a gluten-free diet were tested, as well as sera from an age-matched control group. Measurements to obtain precise quantitative values were made with gliadin antibody-rich serum as reference standard. High titres of gliadin antibodies were found in 18 out of 19 coeliac patients on a normal diet (95%); in patients on a strict gluten-free diet serum values did not exceed 2 S.D. of the control mean. Due to the high sensitivity of the method a low but detectable amount of gliadin antibody was present in the sera of all controls.
We report the case of a 4 1/2-year-old girl admitted to our Hospital because of repeated tonic convulsions. These attacks were triggered by noxious stimuli as well as by emotional stress. Since patient's history was not typical of idiopathic epilepsy, and several electroencephalograms failed to reveal any abnormality, a cardiac basis for the clinical picture was suspected. Resting electrocardiograms and 48-hour ECG recording showed a prolonged Q-T interval, usually responsible for severe cardiac arrhythmias (e.g., ventricular fibrillation or "torsades de pointe"). In our patient the neurologic paroxysmal symptomatology, wrongly considered as idiopathic epilepsy, should be interpreted being due to the underlying cardiac abnormality.
Immunoregulatory T subsets, defined by monoclonal antibodies, were enumerated in children affected by HBsAg-positive chronic active hepatitis. The helper to suppressor/cytotoxic cells ratio was lower in patients than in age-matched controls. The lower ratio was mainly due to an increase of lymphocytes of the suppressor/cytotoxic phenotype. Helper cells were even fewer in severe chronic hepatitis patients, thereby lowering still further the helper/suppressor ratio. Therapy seemed to influence the ratio in patients affected by moderate active chronic hepatitis, for four of eight children treated with azathioprine and prednisone had a ratio within -1 SD of normal values. The increase of the suppressor/cytotoxic cells in patients affected by chronic hepatitis might be a means for limiting virus-induced cell hyperactivity.
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Colostral lymphocytes were studied using two established T-cell markers: intracytoplasmic alpha-naphtyl-acetate esterase (ANAE) staining and membrane receptors for sheep erythrocytes (E rosettes). ANAE staining allowed counting and identification of T-cell subsets independently of the status of membrane structures and receptors frequently altered in colostral cells. The fact that a sizeable number of colostral lymphocytes had the same phenotype as the majority of mature circulating peripheral blood lymphocytes supports the hypothesis that colostral lymphocytes may play a role in protecting neonates against infections, in transferring immune information to the newborn, or in modulating the immune response via release of soluble factors. A considerable percentage of colostral T lymphocytes are ANAE-negative. This phenotype is similar to that observed among thymocytes.
Suppressor cell function was evaluated in children affected by HBsAg-positive chronic active hepatitis. Circulating concanavalin A- (ConA) precultured lymphocytes failed to suppress the proliferative response of autologous responder cells to a mitogen. In four of eight patients with a failure of ConA-induced suppressor activity, indomethacin added during the induction phase of T suppressor cells abolished the defect, indicating that prostaglandin-producing adherent cells may influence ConA-induced suppressor activity. An inverse relationship between suppressor cell activity and the number of suppressor/cytotoxic subsets defined by the OK T8 monoclonal antibody was found. Our findings strongly support the hypothesis that an abnormality in the immunoregulatory system plays a role in the pathogenesis of HBsAg-related chronic active hepatitis. It is also suggested that non-T regulatory cells are implicated in the immunological abnormality in chronic active hepatitis.