What could possibly cause this PBS finding? Seen in picture: agglutination of RBCs

What could possibly cause this PBS finding? Seen in picture: agglutination of RBCs

• A. Paroxysmal cold hemoglobinuria
• B. Multiple myeloma
• C. Mycoplasma pneumoniae infection
• D. Paroxysmal nocturnal hemoglobinuria

Answer: (C)

RBC agglutination in a saline buffer points to cold-reactive antibodies that bind red cells at lower temperatures and cross-link them, causing clumping. The classic trigger for this pattern is an infection with Mycoplasma pneumoniae, which stimulates production of IgM cold agglutinins against red cell antigens and leads to visible RBC clumping in tests like PBS. Donath-Landsteiner antibodies cause a different hemolysis pattern (intravascular destruction that occurs with temperature changes) and aren’t the typical reason for simple RBC agglutination in saline. Paroxysmal nocturnal hemoglobinuria and multiple myeloma don’t ordinarily produce this specific PBS agglutination pattern. So the finding is most consistent with cold agglutinin disease triggered by Mycoplasma pneumoniae infection.

RBC agglutination in a saline buffer points to cold-reactive antibodies that bind red cells at lower temperatures and cross-link them, causing clumping. The classic trigger for this pattern is an infection with Mycoplasma pneumoniae, which stimulates production of IgM cold agglutinins against red cell antigens and leads to visible RBC clumping in tests like PBS. Donath-Landsteiner antibodies cause a different hemolysis pattern (intravascular destruction that occurs with temperature changes) and aren’t the typical reason for simple RBC agglutination in saline. Paroxysmal nocturnal hemoglobinuria and multiple myeloma don’t ordinarily produce this specific PBS agglutination pattern. So the finding is most consistent with cold agglutinin disease triggered by Mycoplasma pneumoniae infection.