Using current methods, the diagnosis of coccidioidomycosis may be delayed and prognosis cannot be precisely determined. Measurement of the coccidioidal-specific cellular immune response could result in both earlier diagnosis and give insight into outcome. Ex vivo release of cytokines (CK) after antigen stimulation of whole blood is a relatively simple method to measure the cellular immune response to infection. Because multiple cytokines (CK) can be measured, a complex picture of the cellular immune response may be elicited. We designed a study to study this assay among among patients referred for newly diagnosed coccidioidomycosis.
Patients seen for the first time for the diagnosis of coccidioidomycosis were eligible for enrollment. Those with a diagnosis of coccidioidal meningitis were excluded. After informed consent, 5 mL of blood was collected into sodium heparin and incubated with 20 µg/mL T27K, a coccidioidal antigen preparation, or nothing (control) for 18 hr at 37°C in 5% CO2. The supernatant was collected and frozen at -80°C until assayed using the Luminex® magnetic bead multiplex system that assays 30 CK.
To date, 18 subjects have entered the study. Their median age was 65 years; 17 were male and 11 were white, non-hispanic. Two were on immunosuppressive therapy. In 15 instances, the patients had pulmonary coccidioidomycosis; two had positive serology only; and one had extrathoracic dissemination. The median time from diagnosis to assay was 14 days.
CK data are available for 12 subjects. Among the 30 CK assayed, the mean antigen-stimulated concentration was ≥10-fold above control for 11. These included three T-helper type 1 CK: interferon-γ (IFN-γ), interleukin-2 (IL-2), and tumor necrosis factor-α (TNF-α); four inflammatory CK: GM-CSF, IL-1β, IL-5, IL-6, and IL-13; and three chemokines: monokine induced by IFN-γ (MIG), macrophage inflammatory protein 1α (MIP-1α), and MIP-1β. All subjects demonstrated elevated levels of these CK. CK among the 19 that were not elevated included IL-4, IL-10, IL-12, and IL-17.
There is a robust expression of CK after ex vivo antigen stimulation in recently diagnosed coccidioidomycosis. These could predate the expression of other tests for the diagnosis of coccidioidomycosis. In addition, the pattern of CK expression could yield information about the prognosis of coccidioidomycosis.
C. T. Nguyen, None
D. Pappagianis, None
N. M. Ampel, None