A case has been reported of enterovirus 71 (EV71)-induced autoimmune hemolytic anemia (AIHA), of which cold agglutin disease (CAD) is a form, in a previously healthy Thai boy.

The case, published in Clinical Medicine Insights: Case Reports, notes that hematologic manifestations associated with EV71 infection are very rare.

“Common manifestations of EV71 infection are vesicular eruptions involving oral mucosa, palms and soles (hand foot and mouth disease),” the authors wrote. “This report describes a case of an 11-year-old boy who developed AIHA after EV71 infection.”

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The patient was a previously healthy boy with no remarkable medical history, who presented with high fever, cervical swelling, and dark urine. The examination showed nonpainful bilateral cervical lymphadenopathy and a tender right cervical lymph node. The urinalysis revealed positive 4+ of protein and marked positive for red blood cells, indicating hemoglobinuria and suggesting intravascular hemolysis. His hemoglobin level was 7 g/dL.

The direct Coombs test was positive 2+ for C3c, 4+ for C3d, and negative for immunoglobulin (Ig) G, IgM, and IgA, leading to a diagnosis of AIHA. The authors reported that they could not perform cold agglutinin titer to rule out CAD or cold agglutinin syndrome; therefore, the exact type of AIHA could not be determined.

Read more about CAD etiology

Associated infections were sought to determine the cause of the AIHA. Enterovirus infection was prevalent at that time in Thailand, and the microneutralization test against E71 in serum revealed elevated levels of neutralizing antibody.

The boy was treated with 60 mg of oral prednisolone per day and had 2 units of red blood cells transfused. Intravenous fluids and other symptomatic treatments were also administered. The patient recovered well within a few days, and the prednisolone was gradually tapered over 10 weeks. The authors recommend EV71 infection be considered as a potential cause of infection-induced AIHA in patients presenting with anemia.


Pattanakitsakul P, Sirachainan N, Apiwattanekul, N. Enterovirus 71-induced autoimmune hemolytic anemia in a boy. Clin Med Insights Case Rep. Published online October 17, 2022. doi:10.1177/11795476221132283