Eosinophil Mediators in Nasal Washes Obtained during Experimental Infections with Rhinovirus-16 in Subjects with and without Asthma
Monday, March 7, 2016: 2:00 PM
Room 502A (Convention Center)
Evan Rajadhyaksha, BS, , , , , , ,
Rationale:  Rhinovirus (RV) infections frequently cause asthma exacerbations in children and young adults. Mechanisms, including the capacity of RV to stimulate Th2 related responses, remain unclear.

Methods: Twelve subjects (ages 19-33) were inoculated with RV 16 (dose = 300 TCID50). They included 7 allergic-asthmatics (AA; total IgE levels 596-1989 IU/ml), and 5 non-atopic controls without asthma (total IgE levels 5 to 42 IU/ml). Eosinophil mediators (ECP [Phadia AB] and EDN [MBL International Corporation]) were measured by ELISA in nasal washes (NW’s) obtained before and during the infection. The results were analyzed in relation to symptoms.

Results: Both ECP and EDN peaked by day 3, paralleling cold symptoms over the first 4 days of the infection. Cumulative values derived from morning NWs during the first four days were significantly higher among AA subjects than controls (ECP: GM = 416 ng/ml and 16.8 ng/ml, respectively, p < 0.05; EDN: GM = 1320 ng/ml and 260.6 ng/ml, respectively, p < 0.05). Compared to baseline values (determined before inoculation), mediator values in NW's increased 20-fold for ECP and 16.6-fold for EDN by day 3 in the AA subjects. By comparison, ECP and EDN levels increased 2.6-fold and 4.7-fold, respectively, among controls.

Conclusions: The increase in eosinophil mediators (ECP and EDN) in nasal washes after RV inoculation was significantly greater in the allergic asthmatics than controls, but the results indicate that RV may also have the capacity to stimulate a Th2 related eosinophil response in the non-allergic, non-asthmatic host.