Bone marrow inhibition induced by azathioprine in a patient without mutation in the thiopurine S-methyltransferase pathogenic site: A case report

Figure 1 Biopsy pathology. A: Thickened basement membrane (hematoxylin-eosin staining, × 400); B: Proliferation of mesangial cells and endothelial cells (periodic acid–Schiff stain, × 400); C: Segmental wire loop (Masson, × 400); D: Segmental dual track formation (periodic acid-silver methenamine, × 400); E and F: Granular deposition along the mesangial region and capillary wall (immunofluorescence, × 400).

Figure 2 Routine blood work. The ‘baseline’ time point is the initiation of azathioprine therapy. Four weeks after azathioprine therapy was stopped, all values returned to their baseline levels. A: Changes in the white blood cell count. The increase in the white blood cell count after azathioprine therapy was stopped was caused by the injection of filgrastim; B: Changes in hemoglobin; C: Changes in the platelet count.

Figure 3 The results of the bone marrow biopsy. A: Results of bone marrow aspiration-myelogram. The myelogram showed low myelodysplasia (G = 52.0%, E = 25.0%, G/E = 2.1/1); cells in the lower and middle granulocyte stages were observed, with a low proportion of mesoblastic granulocytes and a high proportion of lobulated nuclei, with obvious abnormal morphology. Cells in the lower erythroid stage could be seen with a higher proportion of late immature red cells, smaller cell bodies, different sizes of mature red cells, and some hollow enlargement. No obvious abnormality was found in lymphocytes; only one naked nucleus was found in the whole sample, with few platelets and no parasites; B: Bone marrow biopsy showed focal hyperplasia in some areas (70%) and normal hyperplasia in some areas (40%). The proportion of granulocyte red staining was generally normal. Cells at various granulocyte stages were visible, mainly in the middle and late juvenile stage; there were many megakaryocytes, mainly with lobulated nuclei, and some megakaryocytes were less abundant. Reticular fiber staining: Mf0 grade iron staining: Negative.