Acquired bone marrow failure after diphtheria.

Acquired bone marrow failure can result after infections caused by viruses, exposure to toxins, or chemicals. Majority of acquired cases of marrow failure labeled as "idiopathic" are probably immune mediated through activated T-cells and cytokines. We observed pancytopenia in the second week, after pharyngeal diphtheria in a 14-year-old child. Bone marrow examination showed reduced marrow precursors affecting all 3 cell lines. There are no clinical cases of myelosuppression reported in diphtheria infection and this is probably the first reported case of bone marrow failure after diphtheria infection. However, such observations merit further evaluation and confirmation by experimental studies.