[Secretory IgA. Recent progress].

After a brief introduction on the role of the immune system, the paper illustrates the methods of IgA production and their local protective functions. Those pathologies in which the monitoring of IgA levels plays a diagnostic and prognostic role are also described. In conclusion, the current methods used for the correct evaluation of IgA2 titres are discussed: RIA and competitive immunoenzymatic and immunofluorescent tests, although the latter can only be used on biopsy tissue.