Increased plasma levels of soluble CD23 in haemorrhagic fever with renal syndrome; relation to virus-specific IgE.

In 15 consecutive patients hospitalized with nephropathia epidemica, a European form of haemorrhagic fever with renal syndrome (HFRS) caused by Puumala virus, plasma concentrations of soluble CD23 (sCD23) and Puumala virus-specific IgE were determined. In the acute phase of illness, 11/15 patients had increased sCD23 levels (> 91 U/ml), whereas in convalescence, values of 8/10 patients were normalized. Maximal sCD23 values were correlated to maximal concentrations of Puumala virus-specific serum IgE (r = 0.597; P = 0.025). The results are compatible with a known ability of sCD23 to augment IgE production.