[Immunostimulants in chronic infection]

Bacterial extracts are offered as immunostimulatory drugs for the treatment of recurrent infections. A critical review of their postulated immunological efficacy shows that (a) the postulated immunostimulatory efficacy relies mainly on irrelevant in vitro data; (b) the data are inconsistent and contradictory; (c) the immunological efficacy of bacterial extracts given by mouth is doubtful. In addition to the missing immunological basis, various clinical studies have likewise failed to provide a convincing result. The main argument against the use of bacterial extracts as immunostimulants is, however, a wrong indication, as most patients with recurrent infections do not have an immune deficiency but suffer from recurrent infections because of a damaged barrier function (i.e. altered composition of mucus). In spite of these limitations the use of bacterial extracts as "immunostimulants" can be justified, as side effects are very rare, therapy with an "immunostimulant" is attractive for the patient, and the use of antibiotics might be reduced.