A 27-year-old female with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) caused by autoimmune regulator (AIRE) gene mutations, was hospitalized at the National Institutes of Health for routine follow-up of autoimmune pneumonitis. She acutely developed fever (39.9°C), tachycardia (126 beats/minute), and hypotension (58/25 mm Hg) requiring fluid resuscitation and vasopressor support. Laboratory studies revealed leukocytosis (66.4 × 10⁹/L), left shift, metabolic acidosis (pH 7.18), acute renal failure, and shock liver (alanine aminotransferase, 1927 U/L). Peripheral blood smear (panel A; Wright's stain, objective 100×, original magnification ×1000) showed neutrophil toxic granulation (75%; red arrow) consistent with septicemia and Howell-Jolly bodies (2%; black arrow) and echinocytes (14.5%; green arrow) consistent with asplenia. Abdominal computed tomography (panel B) revealed an atrophic spleen. Blood cultures grew Streptococcus pneumoniae, which accounts for ∼50% of septicemia cases in asplenic patients. The patient fully recovered, received vaccination against pneumococcus and other encapsulated microorganisms, and was started on azithromycin prophylaxis due to a prior severe penicillin allergy.

Asplenia occurs during adolescence and early adulthood in ∼15% of patients affected by APECED and is thought to be secondary to a splenic autoimmune attack by autoreactive T cells that escape thymic clonal deletion. Peripheral blood smears should be examined in all APECED patients for early diagnosis of asplenia, which could help prevent potential life-threatening infection sequelae.