Related Experiment Video
Updated: Feb 5, 2026
Plaquing of Herpes Simplex Viruses
Published on: November 5, 2021
Herpes simplex virus encephalitis temporally associated with dimethyl fumarate-induced lymphopenia in a multiple
Paola Perini1, Francesca Rinaldi1, Marco Puthenparampil1
1Multiple Sclerosis Centre of the Veneto Region, Department of Neurosciences, DNS, University Hospital of Padua, Padua Italy.
Background:
Dimethyl fumarate (DMF) is approved as first line therapy for relapsing-remitting multiple sclerosis (RRMS). In some (3%) patients, DMF induces a marked lymphopenia. Herpes simplex encephalitis (HSE) may occur in lymphopenic subjects under treatment with immune-suppressive drugs.
Case Presentation:
We report a case of a 39-year-old female patient with RRMS that developed HSE temporally associated with a marked and sudden drop in lymphocyte count, from 1200/µl to 600/µl, in the peripheral blood. HSE DNA was demonstrated in the cerebrospinal fluid. HSE had the features that characterize HSE occurring in immunosuppressed subjects, i.e. less prominent CSF pleocytosis, bilateral and mainly cortical involvement and less extensive tissue necrosis. Antiviral therapy determined a progressive, although incomplete, improvement. Three months later the patient presented only a mild short-term memory deficit and sporadic episodes of inappropriate emotionality. Lymphocyte count returned to normal values (1120/µl) after DMF discontinuation.
Conclusion:
Our case of HSE in a lymphopenic DMF-treated RRMS patient, points out the necessity of further studies on DMF-related lymphopenia, especially whether it implies an impaired immunity against viruses.
Insights
Dimethyl fumarate (DMF) can cause lymphopenia in multiple sclerosis (MS) patients. This case highlights a potential link between DMF-induced lymphopenia and herpes simplex encephalitis (HSE) in MS.
Area of Science:
- Neuroimmunology
- Infectious Diseases
Background:
- Dimethyl fumarate (DMF) is a first-line treatment for relapsing-remitting multiple sclerosis (RRMS).
- A subset of patients (3%) treated with DMF develop significant lymphopenia.
- Lymphopenia is a known risk factor for opportunistic infections, including herpes simplex encephalitis (HSE).
Observation:
- A 39-year-old female RRMS patient on DMF experienced a sudden drop in lymphocyte count.
- Herpes simplex encephalitis (HSE) was diagnosed, confirmed by viral DNA in cerebrospinal fluid.
- The HSE presentation exhibited characteristics typical of immunosuppressed individuals, including less pronounced CSF pleocytosis and bilateral cortical involvement.
Findings:
- Antiviral therapy led to partial improvement in the patient's neurological symptoms.
- Neurological deficits included mild short-term memory impairment and emotional lability.
- Lymphocyte counts normalized after discontinuing DMF.
Implications:
- This case suggests a potential association between DMF-induced lymphopenia and the development of HSE in RRMS patients.
- Further research is warranted to investigate the impact of DMF-related lymphopenia on immune function against viral infections.
- Clinical vigilance for opportunistic infections is crucial in RRMS patients experiencing significant lymphopenia during DMF therapy.
Related Concept Videos
00:50What are Viruses?
01:49Multiple Allele Traits
01:25Multiple Regression
Farmers can use multiple regression to determine the crop yield based on more than one factor, such as water availability, fertilizer, soil properties, etc. Here, the crop yield is the response or dependent variable as it depends on the other independent variables. The analysis requires the construction of a scatter plot...
01:10¹H NMR of Labile Protons: Temporal Resolution
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
01:19Assessing Body Temperature - Temporal Artery
Step 1: Perform hand hygiene and don a fresh pair of gloves to prevent cross-infection and ensure patient safety.
Step 2: Explain the procedure to the patient to establish trust. Clear communication establishes trust with the patient, ensures they understand what to expect, promotes cooperation, and enhances comfort during the procedure.
Step 3: Assess the patient's...
01:25Multiple Voltage Sources
In series, the positive terminal of one battery is connected to the negative terminal of another battery. Hence, the voltage of each battery is added to give the net voltage, which is increased because each battery boosts the electrons that enter it. The same current flows through each battery because they are connected in series.
Batteries are...