Figure 4. Iron accumulation is not associated with inflammation.

Iba1⁺ microglia/macrophages, MRP14⁺ early-activated peripheral macrophages, and CD3⁺ T cells, as well as superoxide dismutase (SOD, a marker for oxidative stress), are present from the earliest stage of lesion development (nondemyelinated inflammatory nodules [NDIN]), whereas iron accumulation only begins once lesions are 6 weeks old. Note that most Iba1⁺ microglia/macrophages do not contain iron, even in lesions older than 6 weeks. Scale bars: 100 μm. Counterstain: hematoxylin. Lesions selected from marmosets 6, 7, 9, and 10. Note that the lesion shown on the top row, second column, is the same lesion shown in Figure 3A (top row, second column).