An unusual cause of food-induced anaphylaxis in mothers

BACKGROUND

Galacto-oligosaccharides (GOS) are prebiotics added to commercial milk formula of infants and mothers. In recent years, cases of allergy related to GOS in atopic children have been reported in the South East Asian region.

CASE PRESENTATIONS

We describe a series of pregnant (n = 4) and lactating mothers (n = 2) who developed anaphylactic reactions after consumption of maternal milk formula containing GOS. All six subjects had pre-existing atopy and a positive skin prick test to GOS and 5/5 of the subjects who were tested had positive basophil activation tests to GOS. All of the mothers and their babies had normal neonatal outcomes after the reactions.

CONCLUSIONS

The supplementation of GOS into milk and beverages in the Asian region should take into account the rare chance of allergenicity of GOS in the atopic population.

Anaphylaxis to galacto-oligosaccharides--an evaluation in an atopic population in Singapore

Anaphylaxis to galacto-oligosaccharides (GOS), a prebiotic, has been described in atopic patients following its supplementation in commercial milk formula in South-East Asia. The epidemiology of this usual allergy to a carbohydrate is unknown. This study evaluated the prevalence of allergy to two formulations of commercial GOS, Vivinal™ GOS (vGOS) and Oligomate™ , in an atopic cohort. Atopic subjects (n = 487) from two specialist allergy clinics were surveyed via structured questionnaire and underwent skin prick tests to GOS. Subjects with positive skin prick tests to GOS (n = 30, 6.2%) underwent basophil activation tests, and a subset (n = 13) underwent oral challenge tests to both formulations of GOS. Six subjects had positive challenges to vGOS; and none to Oligomate. By extrapolating the BAT and oral challenge results, the prevalence of allergy to vGOS is estimated at up to 3.5% (95% CI 2.2-5.5%) of our atopic population. Our findings show that GOS allergy may be common amongst atopics in Singapore.

Reliability of acute illness dihydrorhodamine-123 testing for chronic granulomatous disease

BACKGROUND

Dihydrorhodamine (DHR) flow cytometric analysis is used to evaluate granulocyte oxidative bursts and is the test of choice for the diagnosis of chronic granulomatous disease (CGD). We present the clinical and DHR test profiles of five subjects assessed during and after acute illness.

METHODS

This was a retrospective report of the findings of five out of a total of one hundred and seventeen patients, whose blood was sent to the laboratory for dihydrorhodamine-123 flow cytometry testing between January 2005 and December 2010. Using whole blood technique and stimulation using phorbol myristate acetate, the results of DHR were expressed as stimulation index and coefficient of variation of histograms of stimulated cells and compared with healthy controls. DHR tests were repeated when the patients had recovered and were clinically well.

RESULTS

These five patients showed abnormal DHR test results during their acute illness, with a stimulation index (SI) lower (p = 0.009) and coefficient of variation (CV) higher (p = 0.009) than controls. The DHR profiles repeated when patients had recovered showed normalization of tests with no significant difference for SI (p = 0.602) and CV (p = 0.917) compared to controls. Wilcoxon Signed Rank tests showed a significant improvement in SI (p = 0.043) and CV (p = 0.043) upon recovery. On follow up, all five patients were well, with no further severe or atypical infections.

CONCLUSIONS

DHR may be transiently abnormal during acute illness, and may therefore not be reliable when assessed during an acute illness. If these subjects had CGD, it would be of a hypomorphic variant that has not previously been described.