Kids with autism, who were born to mothers who had immune conditions during their pregnancy, have more chances to show behavioural and emotional problems, according to a new study.
Results of the UC Davis Health study, published in Translational Psychiatry, examined maternal immune history as a predictor of symptoms in children with autism. The study found that offspring sex may interact with maternal immune conditions to influence outcomes, particularly in terms of a child's cognition.
"We tested the ability of maternal immune history to predict ASD (Autism Spectrum Disorder) symptoms and the possible role that the sex of the offspring plays," said Paul Ashwood, professor of microbiology and immunology and faculty member at the UC Davis MIND Institute.
Maternal immune conditions are caused by a dysfunction of the mother's immune system. They include allergies, asthma, autoimmune diseases, autoinflammatory syndromes and immunological deficiency syndromes.
The researchers enrolled 363 mothers and their children (252 males and 111 females) from the Autism Phenome Project (APP) and Girls with Autism Imaging of Neurodevelopment (GAIN) study at the UC Davis MIND Institute. The median age of the children was three years.
The researchers measured the children's autism severity and assessed a set of behavioural and emotional problems such as aggression and anxiety. They also measured the children's development and cognitive functioning.
The study found that around 27 per cent of the mothers had immune conditions during their pregnancy. Of these mothers, 64 per cent reported a history of asthma, the most common immune condition. Other frequent conditions included Hashimoto's thyroiditis (hypothyroidism), Raynaud's disease (blood circulation disease), alopecia (hair loss), psoriasis (skin disease) and rheumatoid arthritis (joint tissue inflammation).
The study also found that maternal immune conditions are associated with increased behavioural and emotional problems but not reduced cognitive functioning in children with autism.
The difference in boys and girls
According to the Centers for Disease Control and Prevention (CDC), ASD is four times more common among boys than among girls.
"Our study explored whether offspring sex interacts with the presence of maternal immune conditions to influence behavioural outcomes in children. Maternal immune conditions may be one environmental factor, which contributes to the higher male prevalence seen in ASD," said Ashwood.
The study found that a history of maternal immune conditions was more common in male children with ASD (31 per cent) compared to female (18 per cent). Specifically, asthma was twice as common in mothers of male children with ASD than in mothers of female children with ASD.
The study also showed that in cases of ASD where maternal immune conditions are present, female offspring are less likely to be susceptible to adverse cognitive outcomes in response to maternal inflammation than male offspring.
"This critical finding links offspring sex and maternal immune conditions to autism. It provides more evidence that male offspring are at higher risk of adverse outcomes due to maternal immunity activation compared to female offspring," said Ashwood.
