The Warthin-Finkeldey-type giant cell in HIV infection, what is it?

A study was conducted to ascertain the origin of the Warthin-Finkeldey-type giant cell that is common to lymphoid tissues of HIV-infected individuals. Light microscopy (LM) and transmission electron microscopy (TEM), in situ hybridization (ISH) (HIV-specific RNA), and immunohistochemistry (HIV p24, OPD4, CD3, CD45 UCHL, CD21, CD35, S-100, p55 (actin-bundling protein), CD68, HAM56, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and lysozyme) studies were performed on hyperplastic tonsil, adenoid, lymph node, and intestinal MALT specimens from HIV+ patients. Warthin-Finkeldey-type giant cells (WFTGC) and follicular dendritic cells (FDC) shared characteristic morphologic (high N: C ratio; crowded, irregular nuclei; thin filaments with dense bodies; desmosomes; and cilia) and immunophenotypic (CD21+, CD35+, S-100+, p55, and vimentin+) features. Also, transitional forms between binucleated FDC and WFTGC were identified by TEM. TEM and ISH revealed evidence of HIV expression by FDC, but not WFTGC. WFTGC in HIV- lymphoid specimens displayed identical LM and IHC characteristics. The WFTGC in HIV infection appears to represent a multinucleated form of FDC.