MCQ – 74252

A 56 years old female presented in the month of December with chronic fatigue and cyanosis of nose with blue lips and arthralgia. A peripheral blood smear showed the following image. What is the most likely cause of the findings seen?

A.	Clumps of RBCs due to IgG mediated cold autoimmune hemolytic anemia
B.	Clumps of RBCs due to IgM mediated cold autoimmune hemolytic anemia
C.	RBC lysis due to hemoglobinopathy
D.	Clumps of RBCs due to IgG mediated warm autoimmune hemolytic anemia

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Correct Answer � B Explanation

Ans: B. Clumps of RBCs due to IgM mediated cold autoimmune hemolytic anemia

(Ref: Robbins 9/e p643-644)

Cold Antibody Hemolytic Anemia:

• Antibodies bind with antigens (on RBC) better at temperature lower than 37°C.
• Antibodies are called “reactive antibodies”.
• Usually IgM.
• Rarely IgG antibodies.
• E.g. The Donath Landsteiner antibody of Paroxysmal cold hemoglobinuria.