[Contribution of immuno-hematology in understanding autoimmune phenomena]

Acquired hemolytic anemia (AHA) can be considered under four aspects: 1) The nature and specificity of involved autoantibodies correspond to weakly differentiated structures of high frequency but normal human blood group antigens. 2) The pathologic role of autoantibody can be experimentally demonstrated by parallel measures of the specific red cell survival. 3) In certain cases of AHA--secondary to infections (Mycoplasma pneumoniae, infectious mononucleosis) or drugs (methyl dopa), or related to tumours (dermoid ovarian cyste, ovary teratoma) or tissue damages (haemorragic rectocolitis)--the relation between a clinical precise circumstance and the production of autoantibody can actually be demonstrated. 4) In idiopathic AHA, in addition to various autoantibodies, an immunological disorder is observed, including the production of allo- and heteroantibodies and, in 50% of the cases, a global deficit in immunoglobulin. 5) On these bases, the nature of autoimmunity is discussed. If specific modifications can explain secondary AHA, they can hardly account for idiopathic AHA. Cellular non-specific anomalies should be considered.