Drug-induced thrombocytopenia occurs through immune-mediated platelet destruction, and its management is challenging during tuberculosis treatment. Although rifampicin is the most common drug causing thrombocytopenia, isoniazid can also cause thrombocytopenia. We herein report a 75-year-old man who developed thrombocytopenia during tuberculosis treatment. Platelet-associated immunoglobulin G and a drug-induced lymphocyte stimulation test for isoniazid were positive; no other causes of thrombocytopenia were identified. The patient was diagnosed with isoniazid-induced immune thrombocytopenia, and the platelet count normalized after isoniazid discontinuation. We describe the immunological mechanism of thrombocytosis due to isoniazid, an uncommon cause of thrombocytopenia that physicians should be aware exists.

We herein report a case of idiopathic refractory ascites following allogeneic hematopoietic cell transplantation that was successfully treated with ibrutinib. A 39-year-old man presented with massive transudative ascites. Despite a high portal venous pressure, the liver histology showed traces of alloreactivity inconsistent with veno-occlusive disease/sinusoidal obstructive syndrome. Ibrutinib was administered for ascites possibly secondary to portal hypertension associated with the alloreactivity. The ascites dramatically improved, and the portal venous pressure was reduced. This case may help clarify the mechanism through which refractory ascites develops after allogeneic hematopoietic cell transplantation and establish appropriate treatment protocols.