Advertisement

iNKT and memory B-cell alterations in HHV-8 multicentric Castleman disease

Zineb Sbihi, Antoine Dossier, David Boutboul, Lionel Galicier, Christophe Parizot, Amandine Emarre, Bénédicte Hoareau, Nicolas Dupin, Anne-Geneviève Marcelin, Anne Oudin, Claire Fieschi, Félix Agbalika, Brigitte Autran, Eric Oksenhendler and Guislaine Carcelain

Key Points

  • HHV-8 MCD is associated with a decrease of iNKT and memory B cells.

  • iNKT decrease contributes to B-cell abnormalities in coculture experiments.

Publisher's Note: There is an Inside Blood Commentary on this article in this issue.

Abstract

Human herpesvirus 8 (HHV-8) is the causative agent of Kaposi sarcoma (KS) and multicentric Castleman disease (MCD), a life-threatening, virally induced B-cell lymphoproliferative disorder. HHV-8 is a B-lymphotropic γ-herpesvirus closely related to the Epstein-Barr virus (EBV). Invariant natural killer T (iNKT) cells are innate-like T cells that play a role in antiviral immunity, specifically in controlling viral replication in EBV-infected B cells. Decline of iNKT cells is associated with age or HIV infection, both situations associated with HHV-8–related diseases. We analyzed iNKT cells in both blood (n = 26) and spleen (n = 9) samples from 32 patients with HHV-8 MCD and compared them with patients with KS (n = 24) and healthy donors (n = 29). We determined that both circulating and splenic iNKT cell frequencies were markedly decreased in patients with HHV-8 MCD and were undetectable in 6 of them. Moreover, iNKT cells from patients with HHV-8 MCD displayed a proliferative defect after stimulation with α-galactosylceramide. These iNKT cell alterations were associated with an imbalance in B-cell subsets, including a significant decrease in memory B cells, particularly of marginal zone (MZ) B cells. Coculture experiments revealed that the decrease in iNKT cells contributed to the alterations in the B-cell subset distribution. These observations contribute to a better understanding of the complex interactions between HHV-8 and immune cells that cause HHV-8–related MCD.

  • Submitted June 3, 2016.
  • Accepted November 2, 2016.
View Full Text