A case of haemolytic anaemia caused by cold agglutinins.

Background: Cold agglutinins are IgM autoantibodies, which are often detected incidentally. They are rarely pathogenic. Natural cold autoantibodies occur in titers less than 1:64 measured at 4°C and have no activity at temperature higher than 22°C, However pathogenic cold agglutinins causing haemolysis typically have titers well over 1:1000 and may react at 28-31°C or even upto 37°C (wide thermal amplitude). Case Report: We encountered a case of 62-year-old male presenting to Urology department of our hospital in January 2007 with the complains of recurrent haematuria, symptoms of obstruction in the lower urinary tract and progressive weakness. He was subsequently diagnosed as a case of cold agglutinin causing haemolysis. The case came to notice because of the difficulty in carrying out routine investigations in the laboratory due to repeated agglutination and haemolysis. Investigations: • Complete haemogram, peripheral smear examination and blood grouping was done. All the investigations were done while keeping the blood at 37°C. • Direct and indirect Coombs test. Routine urine microscopy. • Biochemical investigations include total and direct bilirubin AST/ALT, Urea, creatinine and LDH. Results: • Macroscopic agglutination was visible in the blood collection tubes. • Hb was 5.6 g% with normal WBCs and platelets count. Corrected reticulocyte count was raised (5%). • Biochemistry indirect hyper bilirubinaemia, increased LDH, normal AST/ALT and creatinine. • Urine was positive for Hb and haemosiderin and showed no RBC in sediments. • X-ray chest was normal. • The serum of the patient could agglutinate all allo-RBC.s in a titer >1:1000 and at a temperature range from 4 to 37°C. • Coombs test was reported as positive for C3d and agglutinins showed anti-I reactivity. Discussion and Conclusion: • Patient was diagnosed to have primary cold agglutinin disease on the basis of the positive Coombs test against C3d and anti-I reactivity. There was no clinical evidence of any other underlying disease. • Patient was refractory to corticosteroids and subsequently managed by Cyclophosphamide with a good response. The case high lights the need for laboratory personnel to be aware of this condition so the clinician can be alerted about this possibility and timely diagnosis made. [ABSTRACT FROM AUTHOR]