Many lymphocytes are present in this field. Two larger, atypical lymphocytes with intact cytoplasm and slightly indented nuclei are seen near the center of this slide. Two other large cells with irregular, trailing cytoplasm are macrophages (histiocytes). Increased lymphocytes may be seen in viral meningoencephalitis, partially treated bacterial meningitis, multiple sclerosis, Guillian-Barre's syndrome, or polyneuritis.