LISBON — Clinically moderate to severe hantavirus infections are invariably characterized by a distinctive pattern of serum lipid changes, reported Dr. Jan Clement at the 12th International Congress on Infectious Diseases.
The size of the lipid perturbations correlates with the severity of the underlying hantavirus infection. And because the lipid changes precede by several days, the deterioration in renal function and worsening thrombocytopenia that mark a serious hantavirus infection, the extent of the lipid abnormalities can be used as an early warning system regarding the viral illness to come, according to Dr. Clement of the Rega Institute for Medical Research at the University of Leuven, Belgium.
This is the first report linking serum lipid changes to the subsequent severity of hantavirus infection, he noted. Although the work was restricted to Belgian hantavirus patients, Dr. Clement has studied numerous cases of the viral infection from disparate areas of the globe and believes the phenomenon occurs worldwide.
He reported on 58 Belgians with serologically confirmed hantavirus infection. Their associated serum lipid changes consisted of a marked reduction in total cholesterol and HDL accompanied by hypertriglyceridemia. Baseline serum lipid levels weren't available for many patients. However, the mean total cholesterol at the peak of the illness was 141 mg/dL, compared with 238 mg/dL after recovery. The perturbation in HDL was even more profound: a mean of 14 mg/dL during the early and peak phases of the illness, compared with 52 mg/dL after recovery. Triglyceride levels rose to a mean of 329 mg/dL during the hantavirus infection, even though some patients experienced anorexia and vomiting, before declining to 199 mg/dL upon recovery, Dr. Clement added at the congress, which was sponsored by the International Society for Infectious Diseases.
There were significant correlations between the extent of hypocholesterolemia and low HDL and the degree of thrombocytopenia and renal impairment. For example, the two patients who developed hantavirus-induced adult respiratory distress syndrome requiring mechanical ventilation had the lowest values of these lipids recorded in the entire study: an average nadir of 53 mg/dL for total cholesterol and 5 mg/dL for HDL. In 38 patients with moderately severe hantavirus infection, defined by a peak serum creatinine in excess of 1.5 mg/dL, the mean nadir total cholesterol was 129 mg/dL. In contrast, total cholesterol bottomed out at a mean of 162 mg/dL in patients with a milder infection (a peak creatinine below 1.5 mg/dL).
The mechanism by which serum lipid changes serve as a predictor of the clinical severity of hantavirus infection is thought to be that the lipid levels provide an indirect measure of proinflammatory cytokine bioactivity, said Dr. Clement.