A, Lung shows severe acute inflammation consistent with acute pneumonia. B, Anterior spinal cord shows diffuse parenchymal lymphocytic host response with neuronophagia of motor neurons by infiltrating lymphocytes. C, Anterior spinal cord characterizes the parenchymal lymphocytes as T cells. D, Anterior spinal cord demonstrates the predominantly perivascular location of B cells. E, Anterior spinal cord demonstrates the lack of activation of the apoptotic pathway by motor neurons. F, Anterior spinal cord demonstrates the T-cell cytolytic protein located on the motor neurons (hematoxylin-eosin, original magnifications ×100 [A] and ×200 [B]; anti-CD3 antibody, original magnification ×100 [C]; anti-CD20 antibody, original magnification ×100 [D]; anti–caspase-3 antibody, original magnification ×40 [E]; anti-perforin antibody, original magnification ×200 [F]).