Volume 23, Number 2—February 2017
Letter
Cerebrospinal Fluid Findings in an Adult with Human Metapneumovirus–Associated Encephalitis
Table
Results of PCR and immunofluorescent assay testing in adult patient with HMPV*
| Test |
Sample type, result or IgG titer |
HMPV IgG index |
|
| Nasopharyngeal swab |
CSF |
||
| Reverse transcription PCR |
Positive (cycle threshold 28.6) |
Negative |
|
| Immunofluorescence assays | |||
| Vero-118 cells infected with HMPV NL/1/00 | 1:8,192 | 1:32 | 0.54 |
| Vero-118 cells infected with HMPV NL/1/99 | 1:8,192 | 1:64 | 1.07 |
*A duplex reverse transcription PCR (r-gene) for detection of human metapneumovirus (HMPV) was performed from a nasopharyngeal swab specimen and cerebrospinal fluid (CSF). For immunofluorescence assays, 96-well plates coated with Vero 118 cells were infected with HMPV NL/1/00 and NL/1/99, respectively. Twenty-four hours later, infected cells were incubated with serial dilutions of patient serum and CSF for 1 h at 37°C. After washing with phosphate-buffered saline, plates were incubated with anti-human IgG conjugated with fluorescein isothiocyanate for 1 h at 37°C. Lowest dilution giving a positive result was determined by UV microscopy. Intrathecal IgG synthesis was calculated using the formula (IgGCSF HMPV/IgGSerum HMPV)/(IgGCSF total/IgGSerum total). Indices below 4 indicate absence of intrathecal IgG antibody synthesis.