Decreased asthma control in older patients with Cytomegalovirus seropositivity

RATIONALE: Cytomegalovirus seropositivity (CMV+) has been associated with poorer clinical outcomes in older patients with several chronic conditions. While the underlying mechanism for this relationship is not fully defined, it likely involves heightened systemic inflammation in combination with a decreased CD4:CD8 ratio usually referred to as the "immune risk profile (IRP)." However, the effect of CMV+ and aging on asthma control has not been studied.

METHODS: The objective of this study was to evaluate the effect of CMV on immune function in young vs. aged asthmatics. Plasma was collected from younger (20-40 years; n=12) and older (>60 years; n=11) inner-city patients with asthma. CMV was detected by ELISA and blood T-helper and T-suppressor (CD4:CD8) ratio measured using flow cytometry. Levels as asthma control were assessed with the Asthma Control Test (ACT).

RESULTS: The aged CMV+ vs. CMV- subjects had a significantly decreased CD4:CD8 ratio (1.15 vs 3.16, p=0.01) and ACT score (13 vs 17, p=0.02). In contrast, the younger CMV+ vs CMV- subjects had a higher CD4:CD8 ratio (3.0 vs 2.2, p=0.02) and no significant differences in ACT scores (16 vs 21, p=0.08). A positive CMV was associated with a 7.7 point reduction in ACT in the aged and a 4.1point reduction in the younger.

CONCLUSIONS: Patients with asthma who are CMV+, older and have decreased CD4:CD8 ratio tend to have worse asthma control. Additional larger studies are needed to validate these preliminary findings, investigate the underlying mechanism and determine if there are clinical benefits to screening older subjects with asthma for CMV.