In vivo and in vitro suppression of lymphocyte function in Aspergillus sinusitis

In about 10% of patients who are operated on for chronic sinusitis, an aspergilloma is found in the affected paranasal sinus. In order to detect possible underlying immune defects, 25 patients with aspergillomas were subjected to an immunological screening program. The data obtained were compared with those of patients with non-mycotic chronic sinusitis and healthy controls. Total lymphocyte counts and immunoglobulin levels were normal in both groups with sinusitis. However, leukocyte subset analyses using membrane fluorescence revealed a significant decrease of CD11+ cells (macrophages, monocytes and natural killer-cells) in both types of sinusitis. Furthermore, a markedly enhanced frequency of CD25+ cells (interleukin 2-receptor-bearing cells), was observed in patients with the aspergillomas. Additionally, peripheral blood lymphocytes in both groups of patients showed a significant reduction in the proliferative response to both T- and B-cell mitogens, with the values for the mitogens ConA and PHA being significantly lower in the aspergilloma patients as compared to those with non-mycotic sinusitis. This lack of lymphocyte stimulation in the aspergilloma group was also manifest in skin tests to recall antigens. These first data suggest that there is an immune deficiency in patients with chronic sinusitis caused by Aspergillus fumigatus. Further studies are needed to clarify if this defect is the cause or the result of the mycotic infection.