The invention relates to a composition strongly enriched with anti-A and/or anti-B polyclonal immunoglobulins, comprising polyclonal human immunoglobulins, characterised in that at least 80 wt.-% of the polyclonal human immunoglobulins present in the composition are anti-A or anti-B polyclonal human immunoglobulins, for use as a drug, particularly in the treatment of polycythemia and/or autoimmune diseases, and in particular peripheral autoimmune thrombocytopenia.
