We read with interest Willner and colleagues' report [1] on the recent hepatitis A epidemic in Tennessee, particularly the incidence of autoimmune hepatitis associated with hepatitis A. We report an unusual association of hepatitis A and immune thrombocytopenic purpura (ITP) seen during the epidemic reported by the authors.

An 18-year-old man presented with a 3-day history of abdominal pain, nausea, vomiting, subjective fever, and dark urine. He had been healthy and had no history of recent travel, tick exposure, or respiratory illness. He denied taking any medications and had no history of alcohol, tobacco, or drug abuse. On physical examination, the patient was hemodynamically stable. He had icteric sclerae, bleeding gums, and purpura over his chest and extremities. Abdominal examination showed tenderness in the epigastrium without distention, guarding, or rigidity. The liver was palpable 2 cm below the right costal margin, and there was no evidence of splenomegaly.

Laboratory testing done at admission showed the following: leukocyte count, 5800 cells/mm³; hematocrit, 49.6%; platelet count, 10 000 cells/mm³; reticulocytes, 0.9%; aspartate aminotransferase level, 570 IU/L; alanine aminotransferase level, 393 IU/L; alkaline phosphatase level, 204 IU/L; total bilirubin level, 5.1 mg/dL; direct bilirubin level, 2.5 mg/dL; creatinine level, 1.2 mg/dL, and blood urea nitrogen level, 6 mg/dL. Prothrombin time was 12.7 seconds (international normalized ratio, 1.1); the partial thromboplastin time was 33.2 seconds; and the fibrinogen level was 350 mg/dL, with no evidence of fibrin degradation products. Urinalysis and chest radiography had normal findings. Viral serology showed presence of hepatitis A IgM antibody and absence of hepatitis C antibody, hepatitis B surface antigen, and anti-hepatitis B core IgM and IgG antibody. Bone marrow aspirate and biopsy revealed normocellular marrow with trilineage hematopoiesis and numerous megakaryocytes. Results of the Coombs test; test for antinuclear antibody; HIV serology; blood cultures; and viral serologies for Epstein-Barr virus, cytomegalovirus, Rocky Mountain spotted fever, and typhus fever were negative. The patient was given platelet transfusions and intravenous immunoglobulin. His platelet count subsequently recovered and he was discharged.

The presence of adequate megakaryocytes in the bone marrow suggests thrombocytopenia secondary to peripheral destruction of platelets. However, the absence of splenomegaly, coexisting viral infections, and autoimmune conditions strongly suggests the relation between hepatitis A and immune-mediated thrombocytopenia. Five other cases of hepatitis A and ITP have been described in the English-language literature [2-5].

In conclusion, the occurrence of autoimmune phenomenon (hemolysis, hepatitis, and ITP) in association with hepatitis A may be more frequent than commonly recognized. The current hepatitis A vaccine is highly effective and safe and should be used more widely.