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In two double-blind trials, volunteers challenged with rhinovirus were treated with aspirin or placebo. Aspirin treatment did not alter the rates of infection or illness but was associated with a moderate reduction in the frequency or severity of some symptoms. The overall benefit in rhinovirus infection was not statistically significant. Aspirin treatment appeared to cause a highly significant increase in the rate of virus shedding in treated subjects. The increase in virus shedding must be considered an adverse event that could influence the course of the disease in the individual and increase the likelihood of the spread of the infection to contacts.

Populations of peripheral blood leukocytes were enumerated in 15 volunteers challenged by intranasal inoculation with rhinovirus serotype 25. The results demonstrated a significant decrease in total lymphocyte count among infected persons on the third day after challenge with the virus (P less than .01). The change in lymphocyte count was associated with a significant decrease in total T cells, as determined by monoclonal antibodies (both T11+ and T3+, P less than .02), but not in B cells (B7+). Among the subsets of T cells, T4+ (T helper/inducer) and T8+ (T suppressor/cytotoxic) lymphocytes both declined in number, but only the change in the T4+ subset was significant. For each of the lymphocyte populations that decreased significantly (T3+, T11+, and T4+) there was a strong correlation with increased severity of symptoms. Persons who had the greatest decrease in total lymphocyte count also shed virus most frequently. The number of nonlymphocyte leukocytes increased with the severity of the symptoms. These data show that T lymphocytes (particularly the T4+ population) are related to both the progression of infection and the symptoms of the rhinovirus common cold.

Leukocyte populations in the secretions of volunteers challenged by intranasal inoculation with rhinovirus serotype 25 were evaluated by means of flow cytometry. With the light-scatter properties of peripheral blood leukocytes as the standard of reference, significant increases (P less than .05) of both lymphocytes and phagocytes (polymorphonuclear leukocytes plus monocytes) were detected in the nasal secretions of persons infected by the viral challenge. There was a direct correlation of nasopharyngeal symptom severity with both the percentage of lymphocytes (P less than .05) and the percentage of phagocytes (P less than .001). Monoclonal antibodies for specific cell-membrane antigens identified the lymphocytes and phagocytes as leukocytes and also demonstrated the presence of a population of monocytic cells during the phase of maximal symptoms. The panel of monoclonals chosen did not unequivocally identify a lymphocyte population except in the presence of nosebleed. However, the results show that flow cytometry can be used to investigate nasal-secretion cell populations during the rhinovirus common cold.

Enviroxime, an inhibitor of rhinovirus replication, was studied in a double-blind, placebo-controlled trial with 99 volunteers. The efficacy of a nasal-spray formulation of enviroxime was tested as pretreatment or as postchallenge treatment for rhinovirus type 4 infection. In the regimens used, drug administration neither prevented infection nor reduced the frequency of specific colds. The mean concentration of enviroxime in nasal washes (12 h after a dose) differentiated two groups of responders. Those in whom the drug concentration exceeded 100 ng/ml had some benefits, although these were statistically insignificant.