title: Unusual spontaneous cold auto-hemagglutination phenomenon in blood units stored under blood bank condition: A retrospective analysis.
abstract: BACKGROUND
  Cold agglutinins (CA) are benign naturally occurring low titer autoantibodies present in most individuals. Those with moderate strength are found in infections, malignancies or autoimmune conditions with diagnostic importance.
  
  
  OBJECTIVE
  Present report deals with CA that brought spontaneous hemagglutination in blood units stored at 2-6°C.
  
  
  METHODS
  Over 32 months period between July 1993 and December 1995, blood units were inspected for spontaneous cold auto-hemagglutination (SpCA) phenomenon. The plasma from these units was separated and investigated for serological specificity using in house red cell panel and standard serological methods.
  
  
  RESULTS
  Among 51,671 blood units, 112 units showed SpCA phenomenon. A rising trend seen in first half of study period significantly fell in remaining half. Specificities of the antibodies detected include anti-I (27), anti-i (53), anti-Pr (21) with remaining few being undetermined specificity. Absorption of serum using enzyme-treated red cells revealed a presence of anti-Pr among the cases, the two of which with new specificities that reacted preferentially with red cells from either new-born or adults and were tentatively named as anti-Pr(Fetal) and anti-Pr(adult), respectively. While 9 cases showed optimum reaction at neutral pH of 7, 68 (62%) cases reacted at pH 5.8 through 8.0, 28 (26%) cases preferred an acidic pH 5.8 and 4 cases opted an alkaline pH 8. Of 28 cases with antibodies preferentially reacting in acidic medium, 17 (60%) cases were anti-i and 7 (25%) cases were anti-Pr.
  
  
  CONCLUSIONS
  Unique SpCA phenomenon observed in blood units stored under blood bank conditions seems to be due to CA developed in response to vector-borne infectious agents. Majority of the cases displayed their specificities, otherwise are rare to be encountered.
authors.affiliation: Surat Raktadan Kendra and Research Center, Surat, Gujarat, India.
authors.forename: Sanmukh R
authors.initials: SR
authors.lastname: Joshi
authors.affiliation: Surat Raktadan Kendra and Research Center, Surat, Gujarat, India.
authors.forename: Rupal A
authors.initials: RA
authors.lastname: Naik
authors.affiliation: Surat Raktadan Kendra and Research Center, Surat, Gujarat, India.
authors.forename: Snehlata C
authors.initials: SC
authors.lastname: Gupte
keywords: Blood donors; blood group specificities; spontaneous cold agglutinins