Specific binding of factor V Leiden experimental antiphospholipid syndrome (FVL-eAPS) mouse sera to normal brain. Representative slides of normal brain stained with pooled serum from adjuvant control and eAPS-FVL mice. Low-magnification microscopy of brain slices stained with (A) pooled adjuvant control sera, (B) FVLQ/+-APS sera, and (C) FVLQ/Q-APS sera showed significant staining of white-matter areas of the hippocampus (black arrows, original magnification × 2). (A, insert) Hippocampal layers. (D,E) Higher-magnification pictures showed significant staining of cells by pooled eAPS-FVLQ/Q sera, compatible with the presence of interneurons outside the main pyramidal cell layers of the cornu ammonis (CA) 1 and 3, and were localized in the stratum radiatum area. Original magnification (D) × 10, (E) × 40.