Sensitized Splenocytes Result in Deleterious Cytokine Cascade and Hyperinflammatory Response in Rats withPneumocystisPneumonia despite the Presence of Corticosteroids

Abstract

The immune response to the opportunistic pulmonary pathogen Pneumocystis can have beneficial and harmful effects on the host despite the presence of corticosteroids. We hypothesized that this deleterious hyperinflammatory response is associated with exaggerated cytokine production. The adoptive transfer of at least 10 7 immune splenocytes reduced the cyst count in rats with corticosteroid-induced pneumocystosis. About 18% of these rats developed clinical illness, an increased lung weight/body weight (LW/BW) ratio, and elevated levels of interleukin 1␣ (IL-1␣), IL-1␤, IL-6, tumor necrosis factor alpha, IL-5, IL-10, and gamma interferon in the lungs. This hyperinflammatory reaction was not observed in rats that remained clinically well or in control rats. Thus, in this model, corticosteroids have little effect on the cytokine cascade or other adverse effects of the host immune response to Pneumocystis.

Therapeutic efficacies of chitosan against Pneumocystis pneumonia of immunosuppressed rat

“…Although a rat model of PCP is usually established by subcutaneous injection cortisone acetate (31)(32)(33), we also successfully constructed PCP model by the intramuscular injection immunosuppressant of dexamethasone sodium phosphate. The higher LW/BW ratio was associated with clinical illness and hyperinflammatory reactions in rats with PCP (34). The study results confirmed that chitosan improved the survival rate of PCP rats and significantly increased weight gain in rats.…”