EBV/HHV-6A dUTPases contribute to myalgic encephalomyelitis/chronic fatigue syndrome pathophysiology by enhancing TFH cell differentiation and extrafollicular activities
Brandon S. Cox, … , William P. Lafuse, Maria Eugenia Ariza
Brandon S. Cox, … , William P. Lafuse, Maria Eugenia Ariza
Published April 28, 2022
Citation Information: JCI Insight. 2022;7(11):e158193. https://doi.org/10.1172/jci.insight.158193.
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Research Article Infectious disease

EBV/HHV-6A dUTPases contribute to myalgic encephalomyelitis/chronic fatigue syndrome pathophysiology by enhancing TFH cell differentiation and extrafollicular activities

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, debilitating, multisystem illness of unknown etiology for which no cure and no diagnostic tests are available. Despite increasing evidence implicating EBV and human herpesvirus 6A (HHV-6A) as potential causative infectious agents in a subset of patients with ME/CFS, few mechanistic studies address a causal relationship. In this study we examined a large ME/CFS cohort and controls and demonstrated a significant increase in activin A and IL-21 serum levels, which correlated with seropositivity for antibodies against the EBV and HHV-6 protein deoxyuridine triphosphate nucleotidohydrolase (dUTPases) but no increase in CXCL13. These cytokines are critical for T follicular helper (TFH) cell differentiation and for the generation of high-affinity antibodies and long-lived plasma cells. Notably, ME/CFS serum was sufficient to drive TFH cell differentiation via an activin A–dependent mechanism. The lack of simultaneous CXCL13 increase with IL-21 indicates impaired TFH function in ME/CFS. In vitro studies revealed that virus dUTPases strongly induced activin A secretion while in vivo, EBV dUTPase induced the formation of splenic marginal zone B and invariant NKTFH cells. Together, our data indicate abnormal germinal center (GC) activity in participants with ME/CFS and highlight a mechanism by which EBV and HHV6 dUTPases may alter GC and extrafollicular antibody responses.

Authors

Brandon S. Cox, Khaled Alharshawi, Irene Mena-Palomo, William P. Lafuse, Maria Eugenia Ariza

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Figure 4

EBV and HHV-6A dUTPase–derived DCM are sufficient to induce in vitro TFH cell differentiation of human naive CD4+ T cells.

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EBV and HHV-6A dUTPase–derived DCM are sufficient to induce in vitro TFH...
(A) Monocyte-derived hDCs (2.5 × 105 cells) were stimulated with dUTPase protein (10 μg/mL) from HHV-6A or EBV or with the human nuclear dUTPase or left untreated (control) for 24 hours. After treatments, culture supernatants were examined for activin A concentration by ELISA. (B and C) Naive CD4+ T cells were isolated from PBMCs as described above (Figure 2 and Methods section) and cultured in vitro with anti-CD3/anti-CD28–coated beads alone (Beads) or in the presence of DCM (Ctl, HHV-6A dUTPase, or EBV dUTPase; 25% vol/vol), with or without IL-12. After 3 days, cells were examined for expression of the TFH markers PD-1, ICOS, and CXCR5 by FACS. (B) Quantitative bar graph of percentage of PD-1+ICOS+CXCR5+ cells differentiated as described above. (C) Representative flow cytometry plots indicating the frequency of ICOS+PD-1+ double-positive cells expressing CXCR5 without IL-12 (left plots) or with IL-12 (far right plots). FACS analyses were conducted on the lymphocyte population, and samples were pregated on live (FVD–) CD4+ cells. Data represent the mean ± SEM of n = 8–12 (A) or n = 5 (B and C) independent experiments. *P < 0.05, **P = 0.01, ****P < 0.0001 of treatment groups versus control by 1-way ANOVA Kruskal-Wallis multiple comparisons test with Dunn’s correction.