Parents of children newly diagnosed with cancer are a highly distressed and potentially vulnerable group. In the hours and days after learning that their child has a life-threatening illness, parents must make decisions about their child’s treatment, continue to parent the child (and other siblings) and maintain the integrity of their couple relationship and family as they reorganize to accommodate prolonged and intrusive treatments. In order to expand upon the psychological literature documenting parental distress, we studied innate immune function in mothers and fathers in the same family within 2 weeks of learning of their child’s cancer diagnosis. Although the findings are unique and intriguing, the sample size is small and the data must be viewed with caution.
As expected, mothers and fathers of children newly diagnosed with cancer reported elevated levels of acute stress, with about 60% meeting diagnostic criteria for ASD. The sample was consistent with the broader sample from which it was drawn and also consistent in rates of acute stress with other samples of parents of pediatric oncology patients [3
]. These caregivers had higher rates of ASD (62%) than caregivers in a sample of parents of children admitted to the pediatric intensive care unit (32%) [17
]. Despite these elevated levels of self-reported distress, the data did not indicate impaired immune function, as measured by NK cell activity, between caregivers in the study and healthy adults (IRG). It is important to note that healthy adults in the IRG comparison group were not matched with the immunity sample on variables of age or ethnicity. No significant correlations between NK cell count by flow cytometry and function or acute stress were observed for mothers or fathers of these subjects. This differs from reports of inverse relationships between measures of psychosocial distress and immunity [20
]; however, these responses may differ with different stressors [21
]. Parenting a child with a life-threatening illness consists of a series of potentially traumatic acute events (e.g., diagnosis, complications, admissions to the intensive care unit) while at the same time involving ‘chronic’ adaptations to provide the treatments and care necessary for survival. This sequence of events differs from ways in which immune function is typically understood in terms of acuity and chronicity [22
]. It is possible that the chronic nature of caregiving for a child with cancer may impact immunity over time.
One of the most unique aspects of this report is the remarkably strong association between mothers’ and fathers’ immune function within the same family (dyad). The exploration of how immune function between intimate family members may be related is highly novel, but consistent with an understanding of stress responses interpersonally. Immunity has been related to marital conflict when a laboratory task was used to evoke disagreement [23
]. At an individual level, marital conflict was associated with a redistribution of lymphocytes and changes in NK cell activity. More specifically NK cells increased during marital conflict and decreased significantly following the conflict. NK cytotoxicity also increased during the task [23
]. These data were reported for individuals, however, and not dyads. When a child is diagnosed with cancer, multiple family members (especially parents) are exposed to this stressor simultaneously. Their reactions to the potentially traumatic event (diagnosis) and their efforts to cope with it over the subsequent hours, weeks and months are intertwined with the reactions and efforts of other family members. These preliminary data suggest that, even when self-reported responses on psychological measures do not show agreement between spouses, there may be commonalities in immune function responses in family members. The data are intriguing for potential long-term understanding of how stressors may influence parents’ physical and emotional well-being as caregivers for their children with cancer or other potentially life-threatening pediatric conditions.
The small sample size in this study precludes further interpretation or conjecture. Gathering data from all participants concurrently would have strengthened the study design. However, given the uniqueness and challenges of studying immune function in samples exposed to a child-related event, the data are noteworthy and signal the importance of studying immune function across individuals in the same family or another close social group.