A 25-year-old female presented in December month with chronic fatigue and cyanosis with bluish lips and arthralgia. Peripheral blood film is shown below. What is the likely cause?

Ans. (a) Cold AIHAThe given figure is of RBC agglutination. The history is suggestive of agglutination occurring in the month of December that is cold induced. Cold Agglutinin Type. This form of immunohemolytic anemia is caused by IgM antibodies that bind red cells avidly at low temperatures (0deg-4degC).