The effect of BCG vaccine at birth on the development of atopy or allergic disease in young children

BACKGROUND

Exposure to infectious diseases may reduce the development of asthma or allergy. In particular, the role of the BCG vaccine in modulating asthma or allergy has been a source of speculation.

OBJECTIVE

To study newborns from 3 international sites to evaluate the prospective effect of BCG vaccine on allergic diseases or atopic development.

METHODS

Infants were enrolled from newborn and well-infant clinics in Thailand, Argentina, and Turkey. The standard BCG vaccine for each country was given at birth. Parents who consented to have their infant included in the protocol completed an allergy family questionnaire. Infants underwent a standard purified protein derivative (PPD) test at 9 to 12 months of age, and the reaction size was measured. At the age of 2 years, the children returned to be studied. Allergy skin tests to common allergens appropriate to location and age were performed, and the parents completed the International Study of Allergy and Asthma in Childhood questionnaire. The PPD reaction size was compared with the presence of atopy and allergy questionnaire responses.

RESULTS

A total of 1,704 infants were studied. Statistical significance was found between a negative PPD response vs any positive PPD response and the risk of having an allergic history at the age of 2 years in Turkey (relative risk, 2.11; 95% confidence interval, 1.25-3.55; P = .005) and Thailand (relative risk, 2.16; 95% confidence interval, 1.18-3.94; P = .02) but not Argentina (relative risk, 1.09; 95% confidence interval, 0.70-1.68; P = .70).

CONCLUSIONS

This study further supports the role of infectious agents in modulating asthma and allergy development.

Accelerated escape from GH autonegative feedback in midpuberty in males: evidence for time-delimited GH-induced somatostatinergic outflow in adolescent boys

A single injected pulse of GH inhibits the time-delayed secretion of GH in the adult by way of central mechanisms that drive somatostatin and repress GHRH outflow. The marked amplification of spontaneous GH pulse amplitude in puberty poses an autoregulatory paradox. We postulated that this disparity might reflect unique relief of GH-induced autonegative feedback during this window of development. The present study contrasts GH autonegative feedback in: 1) normal prepubertal boys (PP) (n = 6; Tanner genital stage I, chronologically aged 8 yr, 9 months to 10 yr, 1 month; median bone age 8.5 yr); 2) longitudinally identified midpubertal boys (MP) (n = 6; Tanner genital stages III/IV, aged 12 yr, 6 months to 15 yr, 6 months; median bone age 15 yr); and 3) healthy young men (YM) (n = 6, aged 18-24 yr; bone age >18 yr). Subjects each underwent four randomly ordered tandem peptide infusions on separate mornings while fasting: i.e. 1) saline/saline infused iv bolus at 0830 h and 1030 h; 2) saline/GHRH (0.3 microg/kg i.v. bolus) at the foregoing times; 3) recombinant human (rh) GH (3 microg/kg as a 6-min square-wave i.v. pulse)/saline; and 4) rhGH and GHRH. To monitor GH autofeedback effects, blood samples were obtained every 10 min for 5.5 h beginning at 0800 h (30 min before GH or saline infusion). Serum GH concentrations were quantitated by ultrasensitive chemiluminometry (threshold 0.005 microg/liter). On the day of successive saline/saline infusion, MP boys maintained higher serum concentrations of: 1) GH ( microg/liter), 2.2 +/- 0.25, compared with PP (0.61 +/- 0.10) or YM (0.88 +/- 0.36) (P = 0.011); 2) IGF-I ( micro g/liter), 493 +/- 49 vs. PP (134 +/- 16) and YM (242 +/- 22) (P < 0.001); 3) T (ng/dl), 524 +/- 58 vs. PP (<20) (P < 0.001); and 4) E2 (pg/ml),19 +/- 3 vs. PP (< 10) (P = 0.030) (mean +/- SEM). Consecutive saline/GHRH infusion elicited comparable peak (absolute maximal) serum GH concentrations (micrograms per liter) in the three study groups, i.e. 18 +/- 5.0 (PP), 9.6 +/- 1.7 (MP), and 14 +/- 5.3 (YM) (each P < 0.01 vs. saline; P = NS cohort effect). Injection of rhGH attenuated subsequent GHRH-stimulated peak serum GH concentrations (micrograms per liter) to 7.8 +/- 1.9 (PP), 5.8 +/- 1.2 (MP), and 4.8 +/- 1.1 (YM) (each P < 0.01 vs. saline; P = NS pubertal effect). GH autofeedback reduced non-GHRH-stimulated (basal) serum GH concentrations by 0.74 +/- 0.28 (PP), 5.7 +/- 1.7 (MP) and 1.4 +/- 0.27 (YM) fold, compared with saline (P = 0.016 for MP vs. PP or YM). In addition to greater fractional autoinhibition, MP boys exhibited markedly accentuated postnadir escape (4.6-fold steeper slope) of suppressed GH concentrations (P < 0.001 vs. PP or YM). Linear regression analysis of data from all 18 subjects revealed that the fasting IGF-I concentration negatively predicted fold-autoinhibition of GHRH-stimulated peak GH release (r = -0.847, P = 0.006) and positively forecast fold-autoinhibition of basal GH release (r = +0.869, P < 0.001). In contrast, the kinetics of rhGH did not differ among the three study cohorts. In summary, boys in midpuberty manifest equivalent responsiveness to exogenous GHRH-stimulated GH secretion; heightened susceptibility to rhGH-induced fractional inhibition of endogenous secretagogue-driven GH release, compared with the prepubertal or adult male; and accelerated recovery of GH output after acute autonegative feedback. This novel tripartite mechanism could engender recurrent high-amplitude GH secretory bursts that mark sex hormone-dependent activation of the human somatotropic axis.

Is serum ECP level helpful in determining discontinuation of inhaled corticosteroid therapy in asthmatic children?

BACKGROUND

Serum eosinophil cationic protein (ECP) has been promoted as a direct marker of eosinophilic inflammation of the airways in patients with asthma. However, its role in monitoring disease activity and management of inhaled corticosteroid (ICS) therapy is not well defined.

METHODS

We determined serum ECP (s-ECP) levels in 95 children (mean +/- SD age, 6.2 +/- 3.9 years) with asthma. At the time of measurements, 34 out of 95 children were symptomatic whereas 61 were in stable condition; and 56 of 95 patients were on maintenance ICS therapy. ICS prophylaxis was withdrawn in 16 of those 56 patients who remained asymptomatic with a dose of 100 micrograms/day of budesonide for 8 weeks. Eight out of these 16 children had to restart ICS therapy within the following 12 weeks, while the remaining 8 children continued to be asymptomatic within the same period.

RESULTS

ECP values and number of patients with a high ECP level (> or = 15 micrograms/L) were significantly higher in the symptomatic group (p = 0.01 and p = 0.006, respectively). Also, ECP levels were significantly lower in the group who achieved clinical remission (n = 16) in which ICS therapy was withdrawn when compared with those who needed to continue ICS prophylaxis. On the other hand, no difference was observed in the comparison of the ECP levels of children who had to restart ICS therapy and those who did not.

CONCLUSION

Our results suggest that, although the determination of s-ECP levels are in accordance with clinical evaluation of disease activity, it is not useful in determining discontinuation of ICS therapy.