We report the case of a patient who developed systemic CMV infection with encephalitis, retinitis, gastritis and colitis after treatment with R-bendamustine. The patient’s clinical history was collected from the electronic medical chart upon signed written informed consent, approved by our Ethics Committee (Helsinki Declaration).
A 75-year-old male was diagnosed with lymphoplasmacytic lymphoma/Waldenström macroglobulinemia with massive bone marrow infiltration in 2016. Past medical history was unremarkable, except for IgM monoclonal gammopathy since 1995.
A 6-cycle R-bendamustine chemotherapy resulted in a good partial response, defined as no extramedullary symptoms with a normal bone marrow biopsy and a reduced, but still detectable, monoclonal IgM protein.
Three months after treatment completion, the patient developed persistent fever and severe weight loss. Laboratory and radiological investigations excluded bacterial infections and extranodal lymphoma localizations. An abdominal CT scan showed parietal thickening of the ileo-caecal region (Fig. 1), and endoscopy revealed mucosal ulcers of both the oesophagus and the colon. Biopsies yielded CMV intracytoplasmic inclusions. HIV antibody testing was negative.
The patient underwent lumbar puncture for the onset of confusion with an abnormal EEG activity, consistent with an acute encephalopathy, despite aspecific dura mater enhancement upon brain MRI imaging, and was thus transferred to our clinical centre. He subsequently developed floaters and blurred vision; fundus oculi examination revealed bilateral CMV retinitis. CMV-DNA PCR was positive in both the peripheral blood (8200 cp/mL) and the CSF (34,500 cp/mL), thus a diagnosis of disseminated CMV infection was made with gastrointestinal, brain and ocular involvement. Induction treatment with ganciclovir (5 mg/Kg q12h) was started, soon after replaced by foscarnet (120 mg/Kg daily) due to the development of severe neutropenia on day 12. Foscarnet was suspended after 2 weeks of treatment due to the deterioration of renal function and electrolyte imbalances. After a 23-day cycle of induction therapy, despite residual plasmatic CMV-DNA (125 cp/mL), maintenance treatment with valganciclovir (900 mg/day) was started, subsequently reduced to 450 mg/day and finally stopped on day 15 because of neutropenia without complete suppression of CMV-viremia (CMV-DNA 399 cp/ml). T-lymphocyte immunephenotype performed 5 months after the last R-bendamustine cycle revealed severe CD4+ depletion (44 cells/μl, 16%), a CD8+ T-cell count of 158/μl (57%), and subversion of the CD4+/CD8+ ratio (0.28) (Fig. 2a).
Three months later the patient experienced reduced visual acuity and visual hallucinations. The fundus oculi examination revealed bilateral retinitis reactivation while no signs of encephalitis were found on brain-MRI. Hallucinations were accounted for as a side effect of levetiracetam, which was promptly discontinued. Plasmatic CMV-DNA resulted positive (487 cp/ml) and induction therapy with valganciclovir (900 mg q12h) was re-started. After 2 weeks, negativization of plasmatic CMV-DNA was observed and valganciclovir was reduced (900 mg/day). After the introduction of valganciclovir and discontinuation of levetiracetam, hallucinations resolved and visual acuity partially recovered as confirmed by the ophthalmologic evaluation that showed no signs of active lesions. At the beginning of suppressive maintenance therapy (9 months after chemotherapy) the CD4+, CD8+ T-cell counts and the CD4+/CD8+ T-cell ratio were 151 cells/μl, 578 cells/μl and 0.25 respectively (Fig. 2a).
Lymphoplasmacytic lymphoma/Waldenström macroglobulinemia is a B-cell lymphoma characterized by an infiltrate of heterogeneous B-cells and IgM hypersecretion [7]. Current therapeutic interventions target only lymphoplasmacytic cells [8], raising questions about the fate of the remaining B-cell subsets. We investigated the B-cell immune profile in this subject, finding a higher proportion of circulating total, activated CD69+ and CD80+ B-cells when compared to our in-house healthy control group (Fig. 2b). We also found a high proportion of B-cells expressing the chemokine receptor CXCR3 (Fig. 2b), known to regulate T-cell chemotaxis and to be expressed by B-cells in some subtypes of B-cell lymphoma [9], as further evidence of the profound imbalance within the B-lymphocyte compartment.
Given the development of disseminated CMV and the persistent CD4+ lymphopenia following a 6-cycle of R-bendamustine, we also sought to investigate T-cell immune-phenotype and function. We first assessed γ/δ T-cells, given their role in the immune response to CMV infection [10] and found a low γ/δ T-cell frequency with a high proportion of CD69- and CD38-expressing cells, suggesting a consumed, yet activated γ/δ compartment (Fig. 2b).
The assessment of CD4+ and CD8+ T-cells revealed a hyperactivated phenotype coupled with an altered distribution of memory and naïve subsets (Fig. 2b-c), compared to in-house healthy donors. Given that our patient displayed a hyperactivated T lymphocyte cell compartment, we next asked whether such generalized T-cell hyperactivation might also specifically affect the patient’s CMV-specific responses. Aiming to specifically dissect CMV-specific response, we therefore comparatively investigated functionally different CD4+/CD8+ T-cell subsets that have been demonstrated to play a central role in CMV-specific immune response [11].
Interestingly, the patient’s PBMC ex vivo challenge to CMV and bacterial stimuli revealed a different functional profile, with evidences of T-cell activation/exhaustion and IFN-γ/TNF-α release upon bacterial, but not CMV challenge (Fig. 2d-e). Likewise, our patient displayed a low CD107a release specifically after CMV challenge with no other differences in cytolytic activity (Fig. 2e), in all suggesting a selective impairment of CMV-specific immunity.
