Jo L.K. Cheung

HUMAN METAPNEUMOVIRUS DETECTION IN PATIENTS WITH SEVERE ACUTE RESPIRATORY SYNDROME

We used a combination approach of conventional virus isolation and molecular techniques to detect human metapneumovirus (HMPV) in patients with severe acute respiratory syndrome (SARS). Of the 48 study patients, 25 (52.1%) were infected with HMPV; 6 of these 25 patients were also infected with coronavirus, and another 5 patients (10.4%) were infected with coronavirus alone. Using this combination approach, we found that human laryngeal carcinoma (HEp-2) cells were superior to rhesus monkey kidney (LLC-MK2) cells commonly used in previous studies for isolation of HMPV. These widely available HEp-2 cells should be included in conjunction with a molecular method for cell culture followup to detect HMPV, particularly in patients with SARS.

High Prevalence of Human Papillomavirus Type 58 in Chinese Women With Cervical Cancer and Precancerous Lesions

The prevalence of human papillomavirus (HPV) among 332 Hong Kong Chinese women with abnormal Papanicolaou smears were determined by polymerase chain reaction and restriction fragment length polymorphism analysis. The overall HPV positive rate was 44.3% with 18.6% (16/86) for normal/inflamed cervices, 36.4% (32/88) for condyloma, 64.7% (33/51) for cervical intraepithelial neoplasia grade 1 (CIN 1), 37.9% (11/29) for CIN 2, 68.3 (41/60) for CIN 3, and 77.8% (14/18) for carcinoma. Double HPV infection was detected in 17 of the 147 positive samples, with a significantly higher proportion in patients with normal or inflamed cervices than those with CIN or carcinoma (31.3% vs 10.5%, P = .029). The six most commonly identified genotypes were HPV 16 (33.3%), HPV 58 (23.8%), HPV 11, 18, 31 (8.8% each), and HPV 33 (6.8%). The worldwide uncommon genotype HPV 58 was found to be the second most common genotype detected in patients with cervical carcinoma (6 of 18 patients). HPV 58 infection showed a significant association with CIN/carcinoma (odds ratio [OR] = 3.98; 95% confidence interval [CI] = 1.22–14.35) and a significant trend of increase in prevalence with increasing severity of cervical lesion (χ2 = 5.84; P = .016). Among Hong Kong Chinese women with abnormal cervical cytology, the detection of HPV 58 carried a positive predictive value of 68.6% for a cervical lesion of CIN 1 or higher severity. The high prevalence of HPV 58 among Chinese women, particularly in patients with carcinoma, has an implication on the design of HPV detection methods and the development of vaccines. J. Med. Virol. 59:232–238, 1999.

Biases in human papillomavirus genotype prevalence assessment associatedwith commonly used consensus primers

Consensus primers targeting human papillomaviruses (HPVs) have biases in sensitivity toward certain HPV types. We applied 3 primer sets (GP5+/6+, MY09/11, PGMY09/11) in parallel on 120 Chinese cervical cancer specimens. GP5+/6+ exhibited a poor sensitivity for HPV52, for which the prevalence among squamous cell cervical cancer was underestimated from 14.6% to 0%. The fact that HPV52 should rank second in prevalence among squamous cell cervical carcinoma in Hong Kong could be missed if GP5+/6+, a worldwide commonly used primer set, was selected for HPV detection. Biases in HPV type‐specific sensitivity may result in misprioritization of vaccine candidates.

Determinants of Cervical Human Papillomavirus Infection: Differences between High- and Low-Oncogenic Risk Types

This cross-sectional survey assessed the determinants of human papillomavirus (HPV) infections among 2080 women who participated in cervical cancer screening. HPVs were typed by restriction and sequencing analyses. The prevalence of HPV was 7.3% (4.2% for high-risk, 1.9% for low-risk, and 2.1% for unknown-risk types). High-risk HPV prevalence decreased with age, whereas low- and unknown-risk HPVs had a second peak in older women. Young age was the only common variable associated with the 3 groups of HPV infections. Lifetime number of sex partners was associated with high- and low-risk types but not with unknown-risk HPVs. Previous Pap smear, treatment for cervical lesions, induced abortion, smoking and having smoker(s) in the family were risk factors for high-risk HPVs. Barrier contraception was protective for low-risk HPVs; current vaginal discharge had a negative association with unknown-risk HPVs. The results indicate that different risk profiles exist for infections with different HPV groups.

Distribution of human papillomavirus types in anogenital warts of men

BACKGROUND A wide spectrum of human papillomavirus (HPV) types can infect the male genitalia. An HPV vaccine covering HPV6 and 11 is now available. Detailed data on the distribution of these two types in anogenital warts is needed to assess the potential benefits of the vaccine. STUDY DESIGN Anogenital wart specimens collected from 130 Chinese men were examined for HPV-type distribution by a method that covers a broad spectrum of high- and low-risk HPVs, and able to reveal multiple types from a single specimen. RESULTS Forty-four (33.8%) of the 130 specimens had a coinfection with multiple HPV types. In 63.1% of cases, only HPV6 and/or HPV11 were/was found. In 26.2% of cases, HPV6 and/or HPV11 were/was found together with one or more other HPV types. In 10.8% of specimens, only non-6/11 HPV types were found. HPV16 and/or 18 were/was found in 12 (9.2%) specimens, with majority (8/12, 66.7%) of which existed as coinfections with HPV6/11. Other HPV types found included HPV39, 51, 52, 55, 59, 61, 62, 68, 58, 72, 81, 83, 84 and CP6108. CONCLUSIONS A substantial proportion of HPV6/11-positive male anogenital warts are coinfected with other HPV types. The efficacy of HPV6/11 vaccine for preventing these lesions needs to be defined before the benefits of vaccinating men can be precisely assessed.

Viral load, E2 gene disruption status, and lineage of human papillomavirus type 16 infection in cervical neoplasia.

The clinical utility of human papillomavirus (HPV) load and integration status remains unclear. We applied refined methods to delineate the viral load, integration status, and lineage of 104 women with HPV-16 monotype infection, including 19 with normal cervices, 9 with histologically proven cervical intraepithelial neoplasia (CIN) 1, 24 with CIN 2, 27 with CIN 3, and 25 with squamous cell carcinoma (SCC). Higher crude viral load, as determined by real-time polymerase chain reaction (PCR) targeting the E7 gene, was observed for SCC but became insignificant after normalization for cell content. Integration was located and quantified by real-time PCRs targeting, respectively, the carboxyl, amino, and hinge domains of the E2 gene. Pure episomal, integrated, and mixed forms were observed in all disease groups. Most E2 gene disruptions involved the amino-terminal, but sparing the hinge region that has been frequently used as a surrogate marker of integration. Large-fragment disruption involving all 3 E2 regions was observed only in the CIN 3 and SCC groups. Altogether, 33.3% of the CIN 3 group and 28.0% of the SCC group harbored pure episomal genomes. The Asian lineage was associated with a higher risk for CIN 3/SCC than the European lineage, and 6 of the 7 large-fragment E2 disruptions were from Asian lineage. The link between viral lineage, integration pattern, and oncogenesis deserves further study.

Human Papillomavirus Type 16 Intratypic Variant Infection and Risk for Cervical Neoplasia in Southern China

A case-control study was conducted on 1986 Hong Kong women to assess the risk of human papillomavirus (HPV) type 16 variants for cervical neoplasia. In total, 255 women were HPV-16 positive and were analyzed for E6 and E7 sequence variation. Two novel substitutions at E6 (T86I and Q116E) and 1 at E7 (R66W) were found. Most HPV-16 variants were of Asian (50.6%) or European (44.3%) lineage, and both lineages showed similar risk associations for high-grade and invasive cervical neoplasia. No increased risk was observed for the subclasses European variant and European 350G, which carry a higher risk for invasive cancer in some Western populations. The E7 N29S substitution, reported to have a higher risk in Korean women, was found equally distributed among normal and various degrees of neoplasia. The epidemiology and risk implication of HPV-16 variant infection in Hong Kong differ markedly from other parts of the world.

Persistent infection of SARS coronavirus in colonic cells in vitro

Severe acute respiratory syndrome coronavirus (SARS‐CoV) can produce gastrointestinal symptoms. The intestinal tract is the only extrapulmonary site where viable viruses have been detected. This study examined seven established human intestinal cell lines, DLD‐1, HCT‐116, HT‐29, LoVo, LS‐180, SW‐480 and SW‐620, for their permissiveness to SARS‐CoV infection. The results showed that only LoVo cells were permissive to SARS‐CoV infection as evident by positive findings from indirect immunofluorescence staining for intracellular viral antigens, in situ hybridization for intracellular viral RNA, and electron microscopy for intracellular viral particles. In contrast to Vero cells, SARS‐CoV did not produce cytopathic effects on LoVo cells. However, LoVo cells were found to be highly permissive for productive infection with a high viral titre (>3 × 107 viral copies/ml) produced in culture supernatant following a few days of incubation. SARS‐CoV established a stable persistent chronic infection that could be maintained after multiple passages. Being a cell line of human origin, LoVo cells could be a useful in vitro model for studying the biology and persistent infection of SARS‐CoV. Our results on the expression of angiotensin‐converting enzyme 2 (ACE2), a recently identified cellular receptor for SARS‐CoV, in these cell lines indicated that it might not be the sole determinant for cells to be susceptible to SARS‐CoV infection. J. Med. Virol. 74:1–7, 2004.

Presence of human herpesviruses 6, 7, and 8 DNA sequences in normal brain tissue

The three novel human herpesviruses (HHV) 6, 7, and 8 are predominantly, but not exclusively, lymphotropic. In an attempt to elucidate their neurotropism in vivo, viral DNA sequences present in fresh autopsy cortical brain tissues obtained from 84 consecutive Chinese subjects (mean age, 66.9 years; range, 21–98 years) were detected by a nested polymerase chain reaction. These patients were apparently immunocompetent and free of clinical signs of viral diseases. HHV‐6 DNA was detected in 36 of 84 (42.9%) patients, and the DNA‐positive and ‐negative groups did not show a significant difference in age or sex distribution. Of the 36 HHV‐6 DNA‐positive cases, 9 (25%) were variant A and 27 (75%) were variant B. In view of the lower prevalence of variant A than variant B in the adult population, the two variants may share a comparable neuroinvasive potential. HHV‐7 and HHV‐8 DNA were detected respectively in three and two patients. The low positive rates of HHV‐7 and HHV‐8 may represent a relatively lower neuroinvasive potential of the viruses. Alternatively, the localization of HHV‐7 and HHV‐8 may be more restricted and the sampled cortical tissues may not represent the most abundant site of persistence in the nervous system. The results provide molecular evidence of the presence of the three newly identified herpesviruses in brain tissue. The pathogenic role for HHV‐7 and HHV‐8, as with HHV‐6, in neurological diseases should not be overlooked. J. Med. Virol. 59:491–495, 1999.

Identification of Human Papillomavirus Type 58 Lineages and the Distribution Worldwide

BACKGROUND Human papillomavirus type 58 (HPV-58) accounts for a much higher proportion of cervical cancers in East Asia than other types. A classification system of HPV-58, which is essential for molecular epidemiological study, is lacking. METHODS AND RESULTS This study analyzed the sequences of 401 isolates collected from 15 countries and cities. The 268 unique concatenated E6-E7-E2-E5-L1-LCR sequences that comprised 57% of the whole HPV-58 genome showed 4 distinct clusters. L1 and LCR produced tree topologies that best resembled the concatenated sequences and thus are the most appropriate surrogate regions for lineage classification. Moreover, short fragments from L1 (nucleotides 6014-6539) and LCR (nucleotides 7257-7429 and 7540-52) were found to contain sequence signatures informative for lineage identification. Lineage A was the most prevalent lineage across all regions. Lineage C was more frequent in Africa than elsewhere, whereas lineage D was more prevalent in Africa than in Asia. Among lineage A variants, sublineage A2 dominated in Africa, the Americas, and Europe, but not in Asia. Sublineage A1, which represents the prototype that originated from a patient with cancer, was rare worldwide except in Asia. CONCLUSIONS HPV-58 can be classified into 4 lineages that show some degree of ethnogeographic predilection in distribution. The evolutionary, epidemiological, and pathological characteristics of these lineages warrant further study.