EFFECT OF IMMUNOSUPPRESSIVE THERAPY ON THE CLINICAL PRESENTATION OF LEGIONELLOSIS

To determine whether the clinical course of legionellosis in patients treated with immunosuppressive agents differs from that seen in other patient groups, data on 52 Finnish patients with legionellosis confirm ed by culture or by the direct immunofluorescent antibody test was rev iewed. Of these patients 44 % were immunosuppressed, 23 % had other un derlying diseases and 33 % had no predisposing conditions. Among those without predisposing conditions, only Legionella pneumophila serogrou p 1 was observed, whereas among the immunosuppressed patients, serogro up 6 dominated. Legionellosis was nosocomial in 73 % of the immunosupp ressed patients and in 33 % of the patients with other underlying dise ases but was travel-associated in 76 % of those without predisposing f actors. The case fatality rate (37 %) was high but was not associated with preceding immunosuppression. These results indicate that although the serogroups and the sources of legionellosis differ in immunosuppr essed patients compared with other groups, the clinical presentation i s not more severe.