The EBV connection: a severe case of GFAP-A with central hypoventilation unresponsive to IVIG and literature review

Abstract

Purpose

Glial fibrillary acidic protein astrocytopathy (GFAP-A) pathogenesis remains uncertain, with potential viral involvement. More clinical cases are needed to deepen our understanding of this disease, along with the exploration of more effective treatment options to provide clinicians with additional choices.

Methods

We report a severe case of GFAP-A secondary to EBV infection, characterized predominantly by central respiratory failure. Additionally, we conducted a literature review summarizing the characteristics of GFAP-IgG-positive patients associated with EBV infection.

Results

Among the 13 patients identified, fever (92.3%) and headache (84.6%) were the most common initial symptoms, while urinary dysfunction was universally present in all patients. Over half of the patients with altered consciousness required endotracheal intubation (7/11, 63.6%), with only one individual experiencing complete resolution without any residual sequela. Only two patients (16.7%) displayed the classic feature of periventricular enhancement on neuroimaging, whereas T2-FLAIR hyperintensities were more prevalent. All patients tested positive for GFAP-IgG in CSF, and 91.7% (11/12) had detectable serum GFAP-IgG antibodies. Three patients (23.1%) achieved full recovery solely through antiviral therapy. In patients receiving various immunotherapies, 60% (6/10) still had residual sequelae.

Conclusion

EBV infection may contribute to the pathogenesis of GFAP-A. GFAP antibody testing is recommended for diagnostic evaluation in cases of central nervous system viral infections presenting with respiratory insufficiency. For severe GFAP-A patients, Protein A immunoadsorption (Protein A IA).

Introduction

Glial fibrillary acidic protein astrocytopathy (GFAP-A) is a central nervous system (CNS) autoimmune disease with unclear pathogenesis [1, 2]. Although associations with viral infections have been reported, putative pathogenic viruses and underlying mechanisms require further investigation [3,4,5,6]. While prior studies have suggested that GFAP-A typically responds favorably to immunotherapies, including corticosteroid therapy and intravenous immunoglobulin (IVIG), there have also been cases where classic treatments showed poor efficacy [6, 7].

Here, we report a severe case of GFAP-A secondary to intracranial Epstein–Barr virus (EBV) infection. In this middle-aged male with autoimmune disease, refractory central hypoventilation stands out as a hitherto underemphasized prominent feature. The man showed poor response to intravenous immunoglobulin therapy, but exhibited symptom improvement after protein A immunoadsorption (IA). Moreover, we conducted a comprehensive review of cases with GFAP-IgG antibody positivity related to EBV, summarized their clinical characteristics, and discussed potential mechanisms by which EBV may trigger GFAP antibody-mediated autoimmune reactions.

Case presentation

A middle-aged patient was admitted to our neurology intensive care unit with conscious disturbance. The symptoms started 8 days prior with headache and fever. Lumbar puncture at local hospital showed elevated opening pressure (> 500 mmH₂O; normal 80–180 mmH₂O), pleocytosis (WBC 144 × 10⁶/L; normal < 10 × 10⁶/L), and increased protein (2.42 g/L; normal 0.15–0.45 g/L). EBV was detected in CSF via next-generation sequencing, though the low viral count (4 sequences) did not prompt immediate concern. Initial head MRI was unremarkable. Despite antimicrobial therapy, the patient became comatose within 3 days, requiring endotracheal intubation, and was subsequently admitted to our hospital. The past medical history included hypertension. Physical examination upon admission revealed coma with Glasgow Coma Scale 4 T (E1VTM3), stiff-neck, and bilateral Kernig’s sign. Lab tests showed leukocytosis (11.16 × 10⁹/L; normal 3.5–9.5 × 10⁹/L) with neutrophilia(9.69 × 10⁹/L; normal 1.8–6.3 × 10⁹/L), lymphocytopenia (0.74 × 10⁹/L; normal 1.1–3.2 × 10⁹/L), and elevated inflammatory markers, C-reactive protein (CRP) (10.9 mg/dL; normal < 0.3 mg/dL), erythrocyte sedimentation rate (ESR) (28 mm/h; normal < 3–11 mm/h), interleukin-6 (IL-6) levels (20.10 pg/mL; normal < 12.1 pg/mL). Meanwhile coagulation function indicated an elevated D-dimer level (13.00 μg/mL FEU; normal < 0.5 μg/mL FEU). Ten tips for serum virus and autoimmune markers for NMDA, MOG, AQP4, LGI1, CASPR2, GABABR, DPPX were negative. Re-evaluation CSF demonstrates elevated opening pressure, increased protein levels, and a lymphocytic pleocytosis with normal glucose and chloride concentrations. The EBV meningoencephalitis was established for positive polymerase chain reaction (2.76 × 10³ copies/mL; normal reference range < 500 copies/mL) and next-generation sequencing (163 sequences) in CSF. Concurrent severe Pseudomonas aeruginosa, Candida, infections were present based on sputum culture and chest CT, while Enterococcus faecalis infection on urine culture. Antimicrobial coverage with IV acyclovir, fluconazole, piperacillin–tazobactam, amikacin, and minocycline was initiated. Due to the severity of the patient’s condition, IVIG (32.5 g/day) was administered over a 5-day period to modulate the immune response. Anticoagulation was started for right lower extremity deep vein thrombosis. Supportive treatment included control of intracranial pressure and vitals, gastric protection, and fluid/electrolyte management.

The patient improved clinically and microbiologically after 2 weeks. The patient’s consciousness has regained clarity, with limb muscle strength restored to Grade 5. Results from sputum culture, urine culture, and pulmonary CT scans all indicate that his infection is under control. However, the middle-aged patient remains unable to breathe independently off the ventilator, as evidenced by arterial blood gas analysis suggesting hypercapnia despite active respiratory rehabilitation efforts. Simultaneously, the patient also presented with urinary dysfunction. Given the patient's improved mental status, albeit still requiring mechanical ventilation support, an electromyography (EMG) was performed, which revealed normal compound muscle action potentials (CMAPs) in the diaphragm but a lack of spontaneous electrical activity during both inspiratory and expiratory phases, while the limb muscles showed normal function. These findings suggest central respiratory failure in the patient. Tracheostomy was performed for airway protection. To investigate the causes of the respiratory failure, we initiated exploration into less common etiologies. GFAP-A was considered based on positive serum and CSF GFAP-IgG by cell-based assay (CBA) (Table 1). Since high-dose steroids were contraindicated due to severe infections, the patient underwent nine sessions of protein A IA (Asahi Kasei Medical Co., Ltd., Japan) with 6000 mL of regeneration plasma per session. As respiratory exercises continued, the patient's respiratory function rapidly improved. After 10 days, the patient was successfully weaned off the ventilator, allowing extubation on day 27. The second brain MRI showed multiple patchy T2-weighted fluid attenuation inversion recovery (FLAIR) hyperintensities in bilateral frontal, parietal, basal ganglia regions, as well as adjacent to the lateral ventricles. Notably, lesions in the thalamus exhibit high signal intensity on gadolinium enhancement, which may underlie the central hypoventilation observed in the patient (Fig. 1). The patient was transferred to a local hospital for further rehabilitation on day 33, at which point the sole remaining complaint was urinary dysfunction. During the 6-month and 12-month follow-ups, the patient had recovered fully without residual deficits (Fig. 2).

Table 1 CSF examinations of the patient

Fig. 1

MRI on D28. A, B In T2-FLAIR images, coronal reveal illustrate high-signal lesions bilaterally in the frontal, parietal regions, basal ganglia, and adjacent to the lateral ventricles. C In T2-FLAIR images, sagittal sections demonstrate high-signal abnormalities in the thalamus. D Upon gadolinium enhancement, sagittal sections confirms the presence of high-signal lesions within the thalamus

Fig. 2

Clinical course and body temperature of the patient

Literature review

On February 5, 2024, a systematic search was conducted across PubMed, Embase, and Medline databases, employing various combinations of the following terms: Epstein–Barr virus, EBV, Human herpesvirus type 4, autoimmune glial fibrillary acidic protein astrocytopathy, GFAP-IgG, GFAP antibody, and GFAP autoimmune. Searches were augmented by incorporating the use of ‘clinical cases’ and ‘case reports’, as well as variants of those keywords. Only articles written in English and published in peer-reviewed journals were considered. Following duplicate data removal, independent screening of titles and abstracts ensued, culminating in a full-text screening process to identify all potentially relevant papers. A manual search of the reference lists within retrieved articles was also carried out to ensure the capture of pertinent studies missed during the initial literature search.

The inclusion criteria for cases were as follows: clear evidence of central nervous system infection with EBV, evidenced by, but not limited to, positive CSF culture, detection of EBV antibodies in CSF, or high EBV sequence reads in CSF metagenomic next-generation sequencing (mNGS); presence of GFAP antibodies in the cerebrospinal fluid and/or serum. We identified a total of 43 cases of positive GFAP antibody associated with EBV infections [3, 7,8,9,10,11,12]. Among these cases, 13 had definitive evidence of CNS viral infection with comprehensive clinical data, summarized in Table 2.

Table 2 Clinical data of patients with GFAP-IgG after EBV infection

This case series included 13 patients (11 males, 2 females; aged 14–86 years) with anti-GFAP antibody following CNS EBV infection. Fever (92.3%) and headache (84.6%) were the most common initial symptoms. Subsequently, various manifestations emerged. All patients suffered from urinary dysfunction (100%), while nine (69.2%) exhibited gastrointestinal dysfunctions. A Japanese study revealed that over half of GFAP-A patients experienced autonomic nervous system dysfunction, primarily manifested as urinary dysfunction [2]. This suggests that impairment to the autonomic nervous system is a common occurrence in GFAP-antibody positive patients. Notably, autonomic dysfunction often does not present as an initial symptom, necessitating meticulous observation by clinicians. Altered consciousness was observed in 11 patients (84.6%), 7 (63.6%) of them required mechanical ventilation. Other symptoms included weakness (76.9%), blurred vision (69.2%), neuropsychiatric abnormalities (69.2%), ataxia (61.5%), seizures (53.8%). Twelve patients underwent MRI, of which 10 (83.3%) demonstrated abnormalities. Lesions were observed in various brain regions, including the cerebral hemispheres, basal ganglia, corpus callosum, brainstem and spine. Neuroimaging findings showed typical periventricular enhancement in two patients (16.7%), while T2-FLAIR hyperintensities were present in five cases (41.6%). In light of previous research [1, 2], T2-FLAIR hyperintensities appear to be more common than typical periventricular enhancement. Besides, signal changes within the corpus callosum occurred in three instances (25%), with one case suggesting reversible splenium lesions. Furthermore, spinal cord abnormalities were detected in four patients. All patients demonstrated elevated white blood cell counts in their CSF; increased protein levels were observed in 12 out of the patients (92.3%). Nine (69.2%) patients had a mild decrease in chloride, among which one patient concurrently presented with low glucose levels and was found to have concurrent tuberculosis infection. The changes in CSF white blood cells, proteins, and glucose are generally consistent with characteristics of viral infections. In all cases, GFAP antibodies were positive in the CSF (100%); for the 12 patients with serum GFAP antibody results, 11 (91.7%) tested positive. The diagnostic significance of CSF GFAP antibodies is higher than that of serum, consistent with previous research findings [20]. All patients received at least one form of antiviral or anti-infective treatment, with two also undergoing anti-tuberculosis therapy. Three patients (23.1%) improved without the use of either corticosteroids or intravenous immunoglobulin (IVIG). One patient, who was administered dexamethasone in addition to antiviral and antibiotic therapy, still exhibited residual urinary dysfunction and lower limb weakness 6 months later; another patient, treated solely with antivirals and IVIG, showed no lingering symptoms following recovery. Eight (61.5%) patients received both corticosteroid therapy and IVIG in conjunction with anti-infective treatments, among which three (37.5%) had complete resolution of all symptoms; two (25.0%) were left with persistent urinary dysfunction, one with both urinary dysfunction and lower limb weakness, and one patient with poor baseline health status, long-term bedridden, and tracheostomy-dependent, eventually succumbed. A favorable response to corticosteroid treatment is considered a characteristic feature of GFAP-A; however, cases of EBV infection followed by GFAP antibody positivity have shown variable responses, including those with poor responsiveness to corticosteroids as well as those who fully recovered solely on anti-infective therapy, suggesting that different underlying mechanisms might be involved, requiring further investigation. It is noteworthy that among the patients requiring mechanical ventilation support (7/13, 53.8%), only one experienced complete improvement across all symptoms, underscoring the need for safer and more efficacious treatment options for critically ill patients.

Discussion

In the case, the patient initially presented with headache and fever, rapidly followed by neuropsychiatric abnormalities and impairment of consciousness. The results from routine CSF examination, mNGS, and PCR led us to consider EBV encephalitis as a diagnosis. Upon the successful management of the infection, the patient regained consciousness and limb muscle strength. However, type II respiratory failure and urinary dysfunction developed. EMG findings suggested that the patient’s respiratory difficulty stemmed from a lack of central drive. As a pivotal integrative center and relay station for autonomic functions, including cardiovascular, respiratory, and visceral reflexes, the thalamus' high-signal lesions on T2-FLAIR and gadolinium enhancement provided radiological evidence supporting the diagnosis of central hypoventilation. The presence of positive GFAP antibodies in both CSF and serum further indicated a possible immune dysregulation within the central nervous system. Standard IVIG treatment failed to alleviate his respiratory distress, while immune adsorption therapy, the patient rapidly improved to the point of meeting the criteria for transfer to a secondary care facility.

EBV, also known as human herpesvirus 4, primarily resides within memory B cells while also infecting NK cells, lymphocytes, astrocytes, and neurons [13]. EBV infiltrates the CNS through the trafficking of infected B cells and by infecting brain microvascular endothelial cells (BMVEC) [14, 15]. It induces CNS damage through various potential mechanisms including direct damage, bystander effects, and molecular mimicry, among others. Emerging data show Epstein–Barr virus-induced gene 2 orchestrates astrocyte migratory behavior and critically modulates T cell-dependent antibody responses, B cell homing and migration within lymphoid tissues [16]. EBV has drawn considerable interest due to its links with conditions including multiple sclerosis, acute cerebellar ataxia, and acute disseminated encephalomyelitis [17,18,19]. Recently, a retrospective study found an increased likelihood of GFAP-IgG positivity in CSF among patients with EBV infections [3].

Despite the lack of definitive diagnostic criteria, GFAP-A patients often exhibit several characteristic features: (1) an acute or subacute onset with predominant clinical manifestations including headache, fever, and neuropsychiatric abnormalities; they may also present with altered consciousness, movement disorders, optic disc edema, and peripheral nerve involvement, among others; (2) MRI findings commonly demonstrate perivascular radial gadolinium enhancement perpendicular to the lateral ventricles, and abnormal signals on T2-weighted and FLAIR sequences are frequently observed; (3) the presence of GFAP antibodies in cerebrospinal fluid (CSF) and/or serum, with a more robust diagnostic significance attributed to CSF antibody positivity; (4) patients may present with coexisting positivity for other CNS autoimmune antibodies or concurrent tumors, such as teratomas or primary central nervous system lymphomas; (5) patients with GFAP-A typically display sensitivity to glucocorticoid treatment [1, 20, 21]. In our case, the patient presented initially with headache, fever, and neuropsychiatric abnormalities, followed by central hypoventilation after the control of infection. According to the synthesis of our review and other case reports [7, 8], although not specifically highlighted, mechanical ventilation seems like a common feature in severe GFAP-A cases. Whether respiratory distress in such patients involves a central pathogenic component remains an area requiring further investigation. The presence of high-signal thalamic lesions observed on T2-FLAIR and gadolinium enhancement in this patient provides a possible explanation for central hypoventilation. Specific thalamic nuclei, such as the paraventricular and dorsomedial nuclei, receive projections from the medullary respiratory center and convey this information to areas within the motor cortex, thereby participating in the modulation of respiratory movements [22]. Furthermore, the thalamus maintains close neural connections with the hypothalamus, a subcortical center for visceral and endocrine activities that is involved in respiratory regulation. Through its interplay with the hypothalamus, the thalamus indirectly contributes to this regulatory process. While linear perivascular radial gadolinium enhancement on MRI is considered a characteristic radiological feature of GFAP-A, it may be absent in potentially up to half of the patients [23, 24]. Based on current findings, high signal intensity on T2-FLAIR sequences appears to be a more common MRI abnormality in GFAP-A patients [2]. Moreover, the MRI linear periventricular enhancement pattern might resolve as the symptom improve, as reported by Cheng et al. [25]. Our patient, who underwent tracheal intubation, an MRI could not be repeated at the peak of symptoms, which might explain the lack of detection of the typical linear periventricular enhancement. Responsiveness to glucocorticoids therapy is another feature of GFAP-A. In this case, due to concurrent systemic infections, the use of glucocorticoids was contraindicated. Instead, intravenous immunoglobulin (IVIG) with immune-modulatory properties was administered alongside anti-infective measures. Despite this, the respiratory failure remained unalleviated, which might be related to the unique pathogenic mechanisms underlying GFAP-A. Ultimately, protein A immunoadsorption therapy was employed, leading to a rapid alleviation of the patient's respiratory distress and successful weaning from mechanical ventilation.

Based on the evidences, we hypothesize EBV CNS infection may trigger autoimmunity activation, leading to GFAP-A (Fig. 3). After infection, these processes can potentially develop: firstly, infected vascular endothelial cells release viral proteins, inflammatory cytokines, free radicals, and excitatory amino acids, thereby provoking neuronal injury [26]. Secondly, infected B cells, along with exosomes carrying their expressed products, enter the CNS and face clearance by CNS immune cells (such as uptake by glial cells or elimination by T cells). This process incites local CNS inflammation, leading to harm to nearby cells and subsequently triggering T cell reactivity against CNS antigens released post-injury (i.e., bystander damage) [27,28,29,30]. Thirdly, molecular mimicry occurs, involving immune cells that possess specificity for EBV antigens, which may cross-react with CNS antigens, resulting in immune cell-mediated CNS damage [31]. Lastly, EBV may directly infect neurons and glial cells, inducing the expression of lytic genes (such as BZLF1) and the release of viral particles [14], ultimately causing cellular damage [32,33,34]. To sum up, EBV-induced GFAP-A involves a variety of immunological processes with the participation of multiple immune-active substances, and patients often have a propensity to develop severe disease, potentially requiring mechanical ventilation support. Moreover, there is a significant likelihood of autonomic nervous system impairment, such as urinary dysfunction. Consequently, in cases where patients exhibit progression of illness post-EBV infection, manifesting consciousness disturbances, respiratory failure, and autonomic nerve injuries, it is recommended to perform GFAP autoantibody testing for definitive diagnosis. In the context of treatment, given the potential for concurrent infections in severe cases and the yet-to-be-fully-elucidated pathogenesis of GFAP-A, immunoadsorption not only targets autoimmune antibodies, but also eliminates myelin debris and immune mediators such as complement proteins and cytokines [35, 36], making it a promising therapeutic option for critically ill patients with GFAP-A secondary to EBV infection (Fig. 3).

Fig. 3

Potential mechanisms of EBV-induced autoimmunity in GFAP-A and therapeutic role of IA

Conclusion

EBV infections may be involved in GFAP-A pathogenesis. For CNS viral infection with hypoventilation, GFAP antibody testing is recommended for diagnosis. Besides, protein A IA effectively removes immunoglobulins, complement, cytokines, and immune mediators. For patients with CNS autoimmunity who cannot receive steroids or have inadequate IVIG response, it may be an effective treatment option.