Efficacy of oral immunotherapy on respiratory infections in hemodialysis patients: a double-blind, placebo-controlled study

Background: Hemodialysis (HD) patients suffer from several immune defects t hat make them prone to develop bacterial infections, in particular respirat ory tract infections (RTIs). Patients and methods: As previous studies have shown that oral immunotherapy with an immunomodulating bacterial extract ( IBE) is effective against RTIs, we decided to test its efficacy and safety in HD patients during a double-blind placebo-controlled prospective study. 40 HD patients with a documented history of RTIs in the previous year were treated for 24 weeks of the endemic season with one capsule daily of IBE (n = 21) or placebo (PL, n = 19). Clinical examinations, measurements of Mac- 1 and gp150.95 on circulating phagocytes and routine laboratory evaluations were performed at week 0, 4, 12 and 24. Patients were also examined at eac h dialysis session allowing an accurate recording of any infectious episode , its treatment and of any untoward effect. Results: During the last period of the study (weeks 13 - 24), IBE significantly reduced the number of pati ents with RTIs and consequently of antibiotic treatment courses as compared to PL (p = 0.018), whereas no difference was detected between IBE and PL d uring periods I (weeks 0 - 4) and II (weeks 5 - 12). There was no differenc e between IBE and PL for other, non respiratory infections. IBE was associa ted at several time points with an increased expression on phagocytes of ad hesion molecules involved in phagocytosis (Mac-1 and gp150.95). However, th e expression of these molecules was not predictive for the occurrence of RT I. IBE was on the whole as well tolerated as PL, 7 patients presented side effects (5 IBE, 2 PL, NS) which led to drop-out in 4 cases (3 IBE, 1 PL). N o serious side effect was recorded, gastrointestinal upset being the most p revalent type. Conclusion: The results of this study indicate that immunomo dulation with selected bacterial extracts constitutes a promising approach for the prevention of bacterial airway infections in groups at risk, such a s HD patients.