Abstract Details

Title Investigating Diagnostic Value of HHV-6 Testing on a CSF Meningitis Encephalitis PCR Panel

Topic Infectious Disease

Presentation(s) P5 - Poster Session 5 (11:45 AM-12:45 PM)

Poster/Presentation
Number 3-006

Objective To determine the value of HHV-6 detection in CSF ME PCR panel in clinical practice.

Background The causal role of human herpesvirus 6 (HHV-6) in neurologic infections in adults is unclear beyond the encephalitic syndrome in patients post-hemopoietic stem cell transplantation (HSCT). Importantly, 1-2% of the human population has HHV-6 DNA benignly integrated into their germline. The FilmArray Meningitis-Encephalitis (ME) multiplex panel is an FDA-approved, nucleic acid-based test that detects 14 microorganisms in cerebrospinal fluid (CSF), including HHV-6. Although HHV-6 is occasionally detected in patients with neurological symptoms, establishing a definitive clinical relationship remains challenging.

Design/Methods All results from ME panel orders 7/2017-12/2024 were retrieved using laboratory information system and retrospective chart review performed.

Results Of 3,281 patients tested, 45 (1.37%) tested positive for HHV-6 on ME panel: 27 males and 18 females aged 18-95 years. Eight of the 45 (17.8%) were initially thought to have possible clinically significant disease, though ultimately only 3 had probable CNS disease (2 recent HSCT recipients with encephalitic syndromes; 1 on immunosuppressant drugs with temporal lobe encephalitis in setting of drug hypersensitivity syndrome). Of the remaining 5 [immunocompetent], 1 had suspected reactivation and 4 had aseptic meningitis managed without antivirals. Ultimately, 93% of positive results were without significant clinical value.

Conclusions Our experience suggests that a positive HHV-6 PCR on ME panel is not clinically significant in most patients, consistent with findings from another academic institution. Positive HHV-6 may be due to false positivity, asymptomatic reactivation, and chromosomal integration, the last of which matches the HHV-6 positivity rate from our panel and expected population frequency of 1-2%. Clinical context must be considered when interpreting ME PCR results and caution should be exercised in interpreting/reporting HHV-6 results in immunocompetent individuals to minimize patient and provider misinterpretations and unnecessary testing/treatment.

Authors/Disclosures
Brenna C. Beezhold PRESENTER	Ms. Beezhold has nothing to disclose.
Una Hadziahmetovic	Miss Hadziahmetovic has nothing to disclose.
Hanna Schaeffeler, BS	Ms. Schaeffeler has nothing to disclose.
Erin Graf, PhD	Dr. Graf has nothing to disclose.
Marie F. Grill, MD (Mayo Clinic)	Dr. Grill has nothing to disclose.

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