Cutavirus Infection in Large Plaque Parapsoriasis, a Premalignant Condition of Mycosis Fungoides

BACKGROUND

Cutavirus (CuV) is associated with mycosis fungoides; however, the CuV status in parapsoriasis en plaques (PP), a premalignant inflammatory condition of mycosis fungoides, has not been fully delineated.

METHODS

Fifty-five Japanese patients with chronic inflammatory skin diseases, including 13 patients with PP, were studied.

RESULTS

CuV DNA was detected significantly more frequently in biopsies of the lesional skin from patients with PP (38% [4/13]) than in those from patients with other inflammatory skin diseases (2% [1/42]; P = 0.009). All CuV-positive PP cases were of the large plaque parapsoriasis (LPP) subtype. The viral loads ranged from 83,450 to 2,164,170 copies/103 cells. We recovered near-full-length CuV sequences from the CuV-positive LPP biopsies, all of which were of the Japanese/Asian genotype. The CuV genome appeared to be present within lymphoid cells infiltrating the epidermis and dermis. CuV NS1 and VP1 gene transcripts were also detected in the affected tissues.

CONCLUSIONS

The preferential detection of high levels of CuV DNA with the expression of viral mRNA suggests a potential role for CuV in the pathogenesis of LPP, making it necessary to study further the impact of CuV, especially regarding the viral genotype, on the outcomes of patients with CuV-positive LPP.

Detection of Merkel cell polyomavirus in multiple primary oral squamous cell carcinomas

Oral microbiome studies have mainly focussed on bacteria, with the relationship between viruses and oral cancers remaining poorly understood. Oral cancers can develop even in the absence of any history of daily smoking or drinking. Oral cancer patients frequently have multiple primary cancers in the oral cavity and other organs, such as the upper gastrointestinal tract. Merkel cell polyomavirus (MCPyV) is a novel oncovirus identified from a subtype of skin cancer in 2008. In this study, we investigated the potential involvement of MCPyV in the pathogenesis of oral squamous cell carcinoma (OSCC). Participants comprised 115 Japanese patients with OSCC (single primary: 109 tumours in 109 patients; multiple primaries: 16 tumours in 6 patients) treated in our department between 2014 and 2017. DNA was extracted from formalin-fixed paraffin-embedded specimens of primary lesions. MCPyV DNA copy counts were analysed by quantitative real-time polymerase chain reaction. Twenty-four of the 115 patients (20.9%) were positive for MCPyV DNA. No association was found between presence or absence of MCPyV DNA and clinical characteristics other than number of primary lesions. The MCPyV DNA-positive rate was significantly higher for multiple primary OSCCs (62.5%, 10/16 tumours) than for single primary OSCCs (16.5%, 18/109 tumours; P < 0.001). Furthermore, MCPyV DNA load was significantly higher for patients with multiple primaries (P < 0.05). MCPyV was observed more frequently and DNA load was significantly higher with multiple primary OSCCs than with single primary OSCC. MCPyV may play some role as an oncovirus for multiple primary OSCCs.

Involvement of cutavirus in a subset of patients with cutaneous T-cell lymphoma with an unfavorable outcome

BACKGROUND

European studies suggest an association between cutavirus (CuV) and cutaneous T-cell lymphoma (CTCL); however, the worldwide prevalence of CuV in patients with CTCL and its prognostic impact remain unknown.

METHODS

We investigated the prevalence and viral loads of CuV DNA using biopsy specimens from the lesional skins of 141 Japanese patients with cutaneous malignancies, including 55 patients with various types of CTCL.

RESULTS

CuV DNA was detected significantly more frequently in biopsies from patients with mycosis fungoides (MF) (38% [13/34]; the most common subtype of CTCL) than in those from patients with other cutaneous malignancies (6% [6/107]; P<0.001). The viral-load range in patients with CuV DNA-positive MF was 23-3922 copies/10³ cells and 8-65 copies/μg of DNA. A phylogenetic analysis using the partial sequences of the CuV viral capsid protein 1 (VP1)/VP2 genes revealed that the CuV sequences identified here were clustered in a Japanese-specific clade distinct from that comprising CuV sequences from European patients with MF. Kaplan-Meier curves and a log-rank test showed that CuV positivity was associated with a shorter disease-specific survival in patients with MF (P = 0.031), whereas no significant difference in overall survival was observed (P = 0.275). No significant correlation was observed between CuV DNA load and survival in patients with CuV-positive MF.

CONCLUSIONS

Our results suggest that CuV is associated with MF in a subset of Japanese patients. Large-scale prospective studies are warranted to clarify the role of CuV status, especially regarding the viral genotype, on adverse outcomes in patients with CuV-positive MF.

Kimura disease forming a human polyomavirus 6–negative parotid gland nodule with prominent squamous metaplasia in a young female: A case report

A case of an asymptomatic 19-year-old woman with Kimura disease presenting with a nodule in the right parotid gland is presented. She had a medical history of atopic dermatitis and noticed a mass on her right-side neck. Cervical lymphadenopathy was clinically diagnosed. The initial management plan was to observe the lesion, which had enlarged from 1 cm to 2 cm in diameter 6 months later. An excisional biopsy was performed, and the pathology confirmed an eosinophil-containing inflammatory parotid gland lesion with many squamous nests and cysts, mimicking a parotid gland tumor. High serum immunoglobulin E levels, peripheral blood eosinophilia, and pathological and genetic diagnoses confirmed Kimura disease. The lesion tested negative for human polyomavirus 6. No recurrence was observed 15 months after the biopsy. The prognosis of Kimura disease without human polyomavirus 6 infection may be favorable; however, further validation of this hypothesis is required as only 5 or 6 cases of Kimura disease have been evaluated for this viral infection. Proliferative squamous metaplasia occurring in parotid gland lesions of Kimura disease is rare and may complicate the diagnostic imaging and pathological diagnosis.

Cutavirus on the skin in an Asian cohort: identification of a novel geographically related genotype

BACKGROUND

Cutavirus (CuV) is the newest human parvovirus and is currently receiving increasing attention because of its possible association with cutaneous T-cell lymphoma. Despite the pathogenetic potential of CuV, it has been detected in normal skin; however, little is known about the prevalence, infection levels, and genetic variations of this virus in the skin of the general population.

METHODS

We investigated the CuV DNA prevalence and viral loads concerning age, sampling location, and gender using 678 skin swabs collected from the normal-appearing skins of 339 Japanese participants aged 2-99 years. Phylogenetic analyses were also conducted based on the near-full-length CuV sequences identified in this study.

RESULTS

Both the CuV DNA prevalence and viral loads were significantly higher in the skin of elderly persons aged ≥60 years compared with those of persons aged < 60 years. CuV DNA tended to persist in the skin of elderly individuals. No significant difference in viral loads was observed between the skin of the upper arm and the skin of the forehead in CuV DNA-positive specimens. Significantly higher viral loads were evident in men vs. women, although no gender-associated differences in viral prevalence were noted. Phylogenetic analyses demonstrated the existence of Japanese-specific viruses that were genetically distinct from viruses prevalent in other areas, especially Europe.

CONCLUSIONS

This large study suggests that high levels of CuV DNA are prevalent on the skin of elderly adults. Our findings also indicated the prevalence of geographically related CuV genotypes. A follow-up study of this cohort should provide helpful information on whether CuV may become pathogenic.

EBV-positive pyothorax-associated lymphoma expresses CXCL9 and CXCL10 chemokines that attract cytotoxic lymphocytes via CXCR3

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) develops in the setting of long-standing inflammation. This type of lymphoma may have specific expression profiles of chemokines involved in the pathogenesis of DLBCL-CI. EBV-positive pyothorax-associated lymphoma (PAL) is a prototype of DLBCL-CI and represents a valuable model for the study of this disease category. Using a panel of PAL cell lines, we found that PAL cells expressed and secreted C-X-C motif chemokine ligands 9 and 10 (CXCL9 and CXCL10), the ligands of CXCR3, in contrast to EBV-negative DLBCL cell lines, which did not. Culture supernatants from PAL cell lines attracted CXCR3-expressing CD4⁺ T cells, CD8⁺ T cells, and CD56⁺ natural killer cells from human peripheral blood mononuclear cells. PAL cells injected into mice also attracted CXCR3-positive cytotoxic lymphocytes that expressed interferon-γ. The expression of CXCL9 and CXCL10 was detected in PAL tumor biopsy samples from patients, and CXCR3-positive lymphocytes were abundant in the tissue samples. Collectively, these findings suggest that CXCL9 and CXCL10 are produced by PAL cells and can elicit cytotoxic responses via CXCR3. This chemokine system is also likely to contribute to tissue necrosis, which is a signature histological feature of DLBCL-CI. Further studies are warranted to determine whether the CXCL9-CXCL10/CXCR3 axis exerts antitumor effects in DLBCL-CI.

Targeting VEGF with bevacizumab inhibits malignant effusion formation of primary human herpesvirus 8‐unrelated effusion large B‐cell lymphoma in vivo

Primary human herpesvirus 8 (HHV8)‐unrelated effusion large B‐cell lymphoma (ELBCL) is recognized as a new clinical entity, but its pathogenesis and therapeutic strategies remain largely unknown. We have generated two mouse models with profuse lymphomatous effusions that resemble HHV8‐unrelated ELBCL occurring in humans, by grafting the cell lines designated as Pell‐1 and Pell‐2. Using these in vivo models, we evaluated the potential role of vascular endothelial growth factor (VEGF) in the pathogenesis of HHV8‐unrelated ELBCL. Both Pell‐1 and Pell‐2 cells consistently produced very high levels of VEGF in mice, in contrast to in vitro findings of relatively low VEGF production in culture medium by HHV8‐unrelated ELBCL cells, especially Pell‐1 cells. Conversely, returning Pell‐1 cells grown in mice to culture medium markedly suppressed VEGF production to the original in vitro level. These findings suggest that the tumour microenvironment plays a role in the steady production of VEGF. We also found that the interaction between HHV8‐unrelated ELBCL cells and peritoneal mesothelial cells increased the production of VEGF in vitro. Finally, we found that bevacizumab significantly suppressed effusion formation and lymphoma cell growth in both mouse models. These results suggest that bevacizumab is a rational approach to the treatment of HHV8‐unrelated ELBCL.

[Histiocytosis and virus: Merkel cell polyomavirus]

Histiocytosis is classified based on proliferating histiocyte-like cells. Langerhans cell histiocytosis (LCH) has several subtypes with various outcomes, from spontaneous to fatal regression, and these subtypes had been managed as different diseases. However, these different names of disease were unified to one disease named histiocytosis X since they are pathologically identical. Presently, LCH has been used as a unified name because proliferating cells have the characteristics of Langerhans cells. Since then, clonality and BRAF mutations have been reported, and their neoplastic characteristics has become clear; however, explaining its various subtypes is difficult with only the neoplastic character. Various relationships/correlations are also known between inflammatory factors and LCH subtypes. We have pointed out that the Merkel cell polyomavirus may be involved in LCH development and LCH is a disease with both neoplastic and reactive characters, that is, "a disease in which abnormal Langerhans-like cells with neoplastic character overreact to some triggers."

Development of a novel cell line-derived xenograft model of primary herpesvirus 8-unrelated effusion large B-cell lymphoma and antitumor activity of birabresib in vitro and in vivo

BACKGROUND

Primary human herpesvirus 8 (HHV8)-unrelated effusion large B-cell lymphoma is a clinical disease entity distinct from HHV8-positive primary effusion lymphoma (PEL). However, the lack of experimental HHV8-unrelated effusion large B-cell lymphoma models continues to hinder the pathophysiologic and therapeutic investigations of this disorder.

METHODS

The lymphoma cells were obtained from the pleural effusion of a patient with primary HHV8-unrelated effusion large B-cell lymphoma and cultured in vitro.

RESULTS

We established a novel HHV8-unrelated effusion large B-cell lymphoma cell line, designated Pell-1, carrying a c-MYC rearrangement with features distinct from those of HHV8-positive PEL. Moreover, we developed an HHV8-unrelated effusion large B-cell lymphoma cell line-derived xenograft model. Pell-1 cells induced profuse lymphomatous ascites and subsequently formed intra-abdominal tumors after intraperitoneal implantation into irradiated nonobese diabetic/severe combined immunodeficient mice. Thus, this xenograft mouse model mimicked the clinical phenomena observed in patients and recapitulated the sequential stages of aggressive HHV8-unrelated effusion large B-cell lymphoma. The bromodomain and extraterminal domain (BET) inhibitors JQ1 and birabresib (MK-8628/OTX015) reduced the proliferation of Pell-1 cells in vitro through the induction of cell cycle arrest and apoptosis. The antitumor effect of BET inhibition was also demonstrated in vivo, as birabresib significantly reduced ascites and suppressed tumor progression without apparent adverse effects in the xenografted mice.

CONCLUSION

These preclinical findings suggest the therapeutic potential of targeting c-MYC through BET inhibition in HHV8-unrelated effusion large B-cell lymphoma.

Prognostic significance of human papillomavirus 16 viral load level in patients with oropharyngeal cancer

Human papillomavirus (HPV) infection in patients with oropharyngeal squamous cell carcinoma (OPSCC) is a major determinant for better prognosis. However, there remain HPV‐positive patients who have poor outcomes. The stratification strategy for detecting high‐risk patients among those with HPV‐positive OPSCC has not been well delineated, especially for Asian patients. We undertook a retrospective cohort study on the survival rate of 89 Japanese patients diagnosed with primary OPSCC. The tumors were concurrently analyzed for the presence of HPV E6 DNA/mRNA, viral DNA load, p16 expression, viral physical status, and viral variant lineage. Human papillomavirus 16 viral DNA was found in 45 (51%) OPSCCs. Human papillomavirus 16 DNA‐positive OPSCCs with higher viral load (classified as HPV16 DNA‐medium/high OPSCCs) showed significantly favorable overall survival and progression‐free survival compared with HPV16 DNA‐positive OPSCCs with lower viral load (<10 copies/cell; HPV16 DNA‐low OPSCCs) and HPV16 DNA‐negative OPSCCs. E6 mRNA expression was observed in all HPV16 DNA‐medium/high OPSCCs but not in HPV16 DNA‐low OPSCCs. Notably, p16‐positive and HPV16 DNA‐negative/low OPSCCs showed significantly worse survival than p16‐positive and HPV16 DNA‐medium/high OPSCCs and resembled HPV‐unrelated OPSCCs with regard to survival and risk factor profile. Although not significant, a trend toward shorter survival was observed for HPV16‐integrated OPSCCs. Phylogenetic analysis revealed two major types of HPV16 variants termed Asian (A4) and European (A1/A2/A3) variants, but no difference in survival between these variants was observed. Altogether, these findings suggest that HPV viral load is a potentially informative factor for more accurate risk stratification of patients with OPSCC.

Human Polyomavirus 6 Detected in Cases of Eosinophilic Pustular Folliculitis

BACKGROUND

Human polyomaviruses (HPyVs) have been associated with several cutaneous inflammatory conditions. More investigation is needed to identify further presentations of cutaneous pathology associated with HPyVs. Our aim was to investigate the possible association of skin-tropic HPyVs with folliculitis, particularly eosinophilic pustular folliculitis (EPF).

METHODS

This study included 55 Japanese patients, comprising 13 patients with EPF and 42 patients with suppurative folliculitis. HPyV DNAs were detected by quantitative polymerase chain reaction. Expression of viral antigen and geographically related viral genotypes were also assessed.

RESULTS

Human polyomavirus 6 (HPyV6) DNA was found in 9 of 13 (69%) patients with EPF, a rate significantly higher than that found in suppurative folliculitis (1/42; 2%). Of the 7 HPyV6 DNA-positive EPF specimens analyzed, 4 were positive for HPyV6 small tumor antigen. All the HPyV6 strains detected in this study were of the Asian/Japanese genotype.

CONCLUSIONS

The predominant detection of HPyV6 DNA and the expression of viral antigen suggest a possible association between HPyV6 infection and EPF in a subset of patients. Worldwide studies are warranted to determine whether Asian/Japanese genotype HPyV6 is associated preferentially with the incidence and pathogenesis of this eosinophil-related skin disease that has an ethnic predilection for the East Asian population.

Prevalence and Viral Loads of Cutaneous Human Polyomaviruses in the Skin of Patients With Chronic Inflammatory Skin Diseases

BACKGROUND

Human skin microorganisms have been associated with various skin diseases. However, most studies have focused on bacterial communities, and little is known about normally resident skin viruses such as the Polyomaviridae and their association with cutaneous disorders.

METHODS

We investigated the infection levels of Merkel cell polyomavirus (MCPyV), human polyomavirus 6 (HPyV6), and human polyomavirus 7 (HPyV7), using triplet skin swabs collected from lesional and nonlesional skins of 86 Japanese patients with inflammatory skin diseases and mycosis fungoides, and from 149 healthy control individuals.

RESULTS

This age-matched case-control study provides the first analyses of the loads of polyomaviruses in association with various skin diseases. The viral loads were significantly higher for HPyV6/HPyV7 and lower for MCPyV in patients with psoriasis. The viral load variation was observed not only at lesion sites, but also at clinically unaffected skin sites in most of the patients. The viral strains tested were all of the Asian/Japanese genotype.

CONCLUSIONS

Our findings suggest a covariation in the infection levels of cutaneous polyomaviruses in certain inflammatory skin conditions. Worldwide prospective longitudinal studies are warranted to understand the influence of such alterations on the pathogenesis of inflammatory skin disorders.

Genetic Variability of the Noncoding Control Region of Cutaneous Merkel Cell Polyomavirus: Identification of Geographically Related Genotypes

Background

Merkel cell polyomavirus (MCPyV) is a ubiquitous cutaneous virus that causes Merkel cell carcinoma, which develops preferentially in white populations from Europe and North America. However, the genomic variations of MCPyV among ethnic groups have not been well delineated, and even less is known regarding alterations in the noncoding control region (NCCR) in the general population.

Methods

MCPyV strains recovered from skin swab specimens from 250 healthy participants with distinct ethnicities and geographic origins were subjected to sequencing analysis of the NCCR.

Results

A 25-base pair tandem repeat caused by a 25-base pair insertion within the NCCR was found predominantly in Japanese and East Asian individuals. Based on the presence of 2 other insertions and a deletion, the NCCR could be classified further into 5 genotypes. This tandem repeat was also found exclusively in the NCCR from Japanese patients with Merkel cell carcinoma, while other genotypes were detected in white patients from Europe and North America.

Conclusions

Our results suggest that the MCPyV NCCR varies according to ethnicity and that assessing the short NCCR sequence provides a rapid and simple means for identification of the Japanese and East Asian variant genotype. It remains to be established whether these NCCR variations are associated differentially with the pathogenesis of MCPyV-driven Merkel cell carcinoma between regions with varying endemicity.

Prevalence and Genetic Variability of Human Polyomaviruses 6 and 7 in Healthy Skin Among Asymptomatic Individuals

Background

Despite the pathogenetic potential of human polyomavirus 6 (HPyV6) and human polyomavirus 7 (HPyV7), they have been found in the normal skin of healthy individuals. However, little is known about the prevalence, infection levels, and geographical variations of these polyomaviruses in the skin.

Methods

Using skin swabs from 470 participants aged 2-98 years, we estimated the prevalence of copy numbers of HPyV6 and HPyV7 with respect to age and ethnicity. Phylogenetic analyses were conducted based on viral sequences obtained from Asian and white populations.

Results

This study provides the first analyses of the age-specific prevalence and levels of HPyV6 and HPyV7 infections in normal skin. Comparisons of age groups revealed that the prevalence and viral loads were significantly higher in elderly persons. Phylogenetic analyses demonstrated the existence of Asian/Japanese-specific strains genetically distinct from strains prevalent in the skin of the white population studied.

Conclusions

This large study suggests that HPyV6 and HPyV7 infections in the skin are highly prevalent in elderly adults. Further research is warranted to understand whether persistent infection with high viral loads in the skin could be a risk factor for the development of HPyV6- and HPyV7-associated skin disorders.

Epstein-Barr virus-positive pyothorax-associated lymphoma expresses CCL17 and CCL22 chemokines that attract CCR4-expressing regulatory T cells

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphomas associated with chronic inflammation (DLBCL-CI) develop in patients with chronic inflammation but without any predisposing immunodeficiency. Given the expression of the EBV latent genes, DLBCL-CI should have mechanisms for evasion of host antitumor immunity. EBV-positive pyothorax-associated lymphoma (PAL) is a prototype of DLBCL-CI and may provide a valuable model for the study of immune evasion by DLBCL-CI. This study demonstrates that PAL cell lines express and secrete CCL17 and/or CCL22 chemokines, the ligands of C-C motif chemokine receptor 4 (CCR4), in contrast to EBV-negative DLBCL cell lines. Accordingly, culture supernatants of PAL cell lines efficiently attracted CCR4-positive regulatory T (Treg) cells in human peripheral blood mononuclear cells. PAL cells injected into mice also attracted CCR4-expressing Treg cells. Furthermore, this study confirmed that CCR4-expressing Treg cells were abundantly present in primary PAL tissues. Collectively, these findings provide new insight into the mechanisms of immune evasion by PAL, and further studies are warranted on whether such mechanisms eventually lead to the development of DLBCL-CI.

Generation and characteristics of a novel "double-hit" high grade B-cell lymphoma cell line DH-My6 with MYC/IGH and BCL6/IGH gene arrangements and potential molecular targeted therapies

“Double-hit” lymphoma (DHL) is a high-grade B-cell lymphoma that harbors concurrent MYC and BCL2 or BCL6 rearrangements. Because cases of MYC/BCL6 DHL are uncommon, most reported conclusions have been based on cases of MYC/BCL2 DHL. Lack of experimental MYC/BCL6 DHL models continues to hinder the pathophysiologic and therapeutic investigations of this disorder. We herein describe a novel MYC/BCL6 DHL cell line, designated DH-My6, carrying both the MYC–IGH and BCL6–IGH fusion genes. Interruptions of MYC and BCL6 expressions using short interfering RNAs and chemical inhibitors led to significant attenuation of DH-My6 cell growth. Greater antitumor effects were found when the cells were treated with a combination of MYC and BCL6 inhibitors. Moreover, the PLK1 inhibitor volasertib and the HDAC inhibitor vorinostat synergized strongly when combined with the bromodomain inhibitor JQ1. DH-My6 is a new well-validated MYC/BCL6 DHL cell line that will provide a useful model for studies of the pathogenesis and therapeutics for the less common DHL tumor type. The rationale for approaches targeting both MYC and BCL6, and in combination with PLK1 or HDAC inhibitors for superior suppression of the aggressive MYC/BCL6 DHL warrants further in vivo testing in a preclinical model.

Merkel cell polyomavirus and Langerhans cell neoplasm

BACKGROUND

The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV.

METHODS

We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data.

RESULTS

We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH.

CONCLUSION

We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Differential gene expression profiling linked to tumor progression of splenic marginal zone lymphoma

The genetic events that lead to aggressive transformation of cases of splenic marginal zone lymphoma (SMZL) after the chronic clinical stage have not been well understood. We aimed to find candidate genes associated with aggressive features of SMZL. We have successfully established two SMZL cell lines, designated SL-15 and SL-22, derived from the same patient's tumor clone in chronic and aggressive phases, respectively. Microarray analysis identified cell cycle-associated genes-specifically PLK1-as the most significantly upregulated in primary aggressive SMZL cells compared with cells from chronic phase. EPHA4 and MS4A1 (CD20) were found to be downregulated dramatically. These gene expression patterns were reproduced in both cell lines. Genetic knockdown of PLK1 resulted in inhibition of cell proliferation and induction of apoptosis in SL-22 cells, which expressed higher levels of PLK1 than SL-15 cells. SL-22 cells needed higher concentrations of chemical PLK1 inhibitors to achieve greater effects. In addition, we found homozygous deletion of the MS4A1 gene as a newly identified molecular mechanism of CD20-negative conversion. Our findings are expected to stimulate further studies on whether PLK1 could be a potential therapeutic target for this tumor. Furthermore, cases with CD20-negatively converted lymphomas should be screened for the genomic loss of MS4A1.

High load of Merkel cell polyomavirus DNA detected in the normal skin of Japanese patients with Merkel cell carcinoma

BACKGROUND

Although Merkel cell polyomavirus (MCPyV) has the potential to cause Merkel cell carcinoma (MCC), it is also found in the normal skin of healthy individuals. However, the mechanism for transformation of MCPyV to an oncogenic form is unknown.

OBJECTIVES

To investigate the levels of MCPyV infection in the normal skin patients with MCC compared with those in a control cohort.

STUDY DESIGN

We studied a total of six Japanese patients with cutaneous MCC. Sun-exposed and sun-unexposed skin swabs were obtained and analyzed for MCPyV loads using quantitative real-time polymerase chain reaction.

RESULTS

At first, we found a patient with MCC carrying an extremely high load of MCPyV DNA in normal skin. This unique case prompted us to further explore the levels of MCPyV as skin microbiota in patients with MCC. We showed that MCPyV DNA levels were significantly higher in swabs obtained from normal skin samples of six patients with MCC compared with those from 30 age-matched healthy individuals and 19 patients with other cutaneous cancers. Whereas MCPyV strains obtained from the normal skin of patients with MCC had gene sequences without structural alterations, sequences of the tumor-derived strains showed truncating mutations or deletions.

CONCLUSIONS

Although the number of patients with MCC studied was small, our findings suggest that MCC may occur with a background of high MCPyV load in the skin, and are expected to stimulate further studies on whether such skin virome levels could be one of predictive markers for the development of MCC.

Epstein-Barr Virus-Positive Pyothorax-Associated Lymphoma Arising from a Posttraumatic Empyema

Pyothorax-associated lymphoma (PAL) develops from a pyothorax caused by an artificial pneumothorax created during the treatment of pulmonary tuberculosis or tuberculous pleuritis. We report the first case of Epstein-Barr virus (EBV)-positive PAL arising from a posttraumatic empyema. A 75-year-old woman with chronic posttraumatic empyema presented with a tumor, which was connected to the wall of a pyothorax in the right thoracic cavity. She had a history of trauma to the right chest, which had occurred at the age of 45 years and had caused the chronic posttraumatic empyema. Pathological features of the resected tumor were conclusive for a diagnosis of EBV-positive PAL. Although neither postoperative chemotherapy nor radiotherapy was performed, remission was maintained for 3 years until recurrence in the liver. Combination chemotherapy led to complete remission, and 9 years after the initial diagnosis of PAL, the patient is still alive. An intriguing finding is the phenotypic alteration during the disease course. Although the primary tumor was negative for CD20 and CD3, the recurrent tumor expressed both of these molecules. We discuss this case of PAL, which was not a complication of lung tuberculosis, and the aberrant chronological phenotypic change observed in the lymphoma cells, and compare it with a usual case of PAL.

Prevalence of human cytomegalovirus, polyomaviruses, and oncogenic viruses in glioblastoma among Japanese subjects

Background

The association between human cytomegalovirus (HCMV) and glioblastoma multiforme (GBM) is becoming a new concept. However, information on the geographic variability of HCMV prevalence in GBM remains scarce. Moreover, the potential roles of various viruses, such as polyomaviruses and oncogenic viruses, in gliomagenesis remain unclear. Our aim was to investigate the prevalence of HCMV in GBM among Japanese patients. Furthermore, this was the first study that evaluated infection with four new human polyomaviruses in GBMs. This study also provided the first data on the detection of human papillomavirus (HPV) in GBM in the Eastern world.

Methods

We measured the number of various viral genomes in GBM samples from 39 Japanese patients using real-time quantitative PCR. The tested viruses included HCMV, Merkel cell polyomavirus, human polyomavirus (HPyV) 6, HPyV7, HPyV9, Epstein–Barr virus, human herpesvirus 8, and HPV. Our quantitative PCR analysis led to the detection of eight copies of the HCMV DNA mixed with DNA extracted from 10⁴ HCMV-negative cells. The presence of HCMV and HPV genomes was also assessed by nested PCR. Immunohistochemical study was also carried out to detect HPV-derived protein in GBM tissues.

Results

The viral DNAs were not detectable, with the exception of HPV, which was present in eight out of 39 (21%) GBMs. All HPV-positive cases harbored high-risk-type HPV (HPV16 and HPV18). Moreover, the HPV major capsid protein was detected in GBM tumor cells.

Conclusions

In contrast with previous reports from Caucasian patients, we did not obtain direct evidence in support of the association between HCMV and GBM. However, high-risk-type HPV infection may play a potential etiological role in gliomagenesis in a subset of patients. These findings should prompt further worldwide epidemiological studies aimed at defining the pathogenicity of virus-associated GBM.

PCR array analysis of gene expression profiles in chronic active Epstein-Barr virus infection

To determine the host cellular gene expression profiles in chronic active Epstein-Barr virus infection (CAEBV), peripheral blood samples were obtained from three patients with CAEBV and investigated using a PCR array analysis that focused on T-cell/B-cell activation. We identified six genes with expression levels that were tenfold higher in CAEBV patients compared with those in healthy controls. These results were verified by quantitative reverse transcription-PCR. We identified four highly upregulated genes, i.e., IL-10, IL-2, IFNGR1, and INHBA. These genes may be involved in inflammatory responses and cell proliferation, and they may contribute to the development and progression of CAEBV.

Phylogenetic analysis of Merkel cell polyomavirus based on full-length LT and VP1 gene sequences derived from neoplastic tumours in Japanese patients

Most Merkel cell polyomavirus (MCPyV) gene sequences have been reported from Western countries and few data are available for the virus sequences from other geographical areas, especially Asia. Thus, we performed phylogenetic analyses based on the nucleotide sequences of the full-length large T-antigen (LT) and viral protein 1 (VP1) genes derived from a variety of cancers in Japanese patients and compared them with sequences from Caucasians. The LT and VP1 gene-based phylogenetic trees identified two main genetic clades. One clade comprised strains isolated from Caucasians, whereas all of the Japanese tumour-derived MCPyV strains belonged to another clade. These findings confirm that most of the MCPyV strains present in Japan form a clade, distinct from Caucasian strains.

Genotypic characteristics of a Mycobacterium sp. isolated from yellowtail Seriola quinqueradiata and striped jack Pseudocaranx dentex in Japan

In Japan, a Mycobacterium marinum-like mycobacterium was isolated from the yellowtail, Seriola quinqueradiata. The species was identified as M. marinum by a commercial mycobacterial DNA-DNA hybridization kit. Nevertheless, PCR restriction analysis of the DNA of its RNA polymerase β-subunit gene definitively showed that this Mycobacterium sp. was M. ulcerans. PCR analysis revealed the genotypic characteristics of M. ulcerans in the Mycobacterium sp., only the mup053 gene sequence being absent, as has been found previously in other piscine mycobacteria such as M. marinum strains DL240490 and DL045 and M. pseudoshottsii. With one exception, this Mycobacterium sp. and M. pseudoshottsii had identical 16S rRNA gene sequences, which is also probably true of M. marinum strains DL240490 and DL045. Similarly, according to comparisons of the 16S rRNA gene, ITS region, and hsp65 gene sequences, this Mycobacterium sp. is more closely related to M. pseudoshottsii than to M. ulcerans or M. marinum. A PCR product of approximately 2000 bp was amplified from region of difference 9 in the Mycobacterium sp. The nucleotide sequence revealed insertion of IS2404, the sequence of which is 1366 bp long. The novel single nucleotide polymorphisms identified in this region distinguished this Mycobacterium sp. from M. marinum strain DL240490 and M. pseudoshottsii. The present findings raise the possibility that these species have a common ancestor. Further studies are required to improve our understanding of the relationship between their geographical origin and genetic diversity.

Novel human polyomaviruses, Merkel cell polyomavirus and human polyomavirus 9, in Japanese chronic lymphocytic leukemia cases

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the rarest adult leukemia in Japan, whereas it is the most common leukemia in the Western world. Recent studies from the United States and Germany suggest a possible etiological association between Merkel cell polyomavirus (MCPyV) and CLL, although no data have been reported from Eastern countries. To increase the volume of relevant data, this study investigated the prevalence and DNA loads of MCPyV and human polyomavirus 9 (HPyV9), another lymphotropic polyomavirus, in Japanese CLL cases.

FINDINGS

We found that 9/27 CLL cases (33.3 %) were positive for MCPyV using quantitative real-time polymerase chain reaction analysis. The viral DNA loads ranged from 0.000017 to 0.0012 copies per cell. All cases were negative for HPyV9. One MCPyV-positive CLL case was evaluated by mutational analysis of the large T (LT) gene, which indicated the presence of wild-type MCPyV without a nucleotide deletion. DNA sequence analysis of the entire small T (ST) gene and the partial LT gene revealed that a Japanese MCPyV isolate, designated CLL-JK, had two nucleotide gaps when compared with the reference sequence of the North American isolate MCC350.

CONCLUSIONS

This study provides the first evidence that MCPyV is present in a subset of Japanese CLL cases with low viral DNA loads. MCPyV and HPyV9 are unlikely to contribute directly to the development of CLL in the majority of Japanese cases. MCPyV isolated from the Japanese CLL cases may constitute an Asian group and its pathogenicity needs to be clarified in future studies.

Promoter methylation of the bone morphogenetic protein 6 gene in multiple myeloma

Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor-β superfamily, are multifunctional signaling molecules that have become of increasing interest in cancer research. Recent observations suggest that alterations in BMPs and BMP signaling are associated with tumorigenesis and disease progression in various types of malignancies. This study investigated the methylation status of the BMP6 gene promoter in various types of plasma cell proliferative disorders by combined bisulfite restriction analysis. While BMP6 methylation was not detected in any samples from monoclonal gammopathies of undetermined significance, intramedullary multiple myeloma (MM), plasma cell leukemia or solitary plasmacytoma, both case studies and cell line studies showed that multiple extramedullary plasmacytoma (MEP) consistently carried a methylated BMP6 promoter. The BMP6 methylation-positive MEP was an aggressive form of MM with extremely high levels of serum lactate dehydrogenase (LDH). Bisulfite sequencing analysis confirmed intensive methylation at CpG sites of the BMP6 promoter region. The methylation of BMP6 was correlated with decreased levels of mRNA transcripts. Expression of BMP6 was restored by the demethylating agent 5-aza-2'-deoxycytidine, suggesting that the methylation is associated with transcriptional silencing. Our study implied that BMP6 promoter methylation is not a common event in MMs, but occurs in aggressive MEP. These findings warrant further investigation to clarify whether BMP6 methylation together with elevated LDH could be a marker of poor prognosis in MEP patients who should be considered for early intensive treatment.

[Senning operation for transposition of great arteries in a premature baby]

A male baby was delivered by emergency cesarean section due to fetal distress at 30 weeks of gestational age with a birth weight of 813 g. By fetal echocardiography, the patient had been diagnosed with transposition of great arteries (type 1). Early two-staged arterial switch operation was planned after 34 gestational age avoiding intracranial hemorrhage under cardiopulmonary bypass. At 19 days of life, vegetation was revealed on the pulmonary valve by echocardiography, so he was diagnosed as infectious endocarditis. Cefotaxime and gamma-globulin were given intravenously for 4 weeks. While waiting for the increase in the body weight, desaturation from chronic respiratory distress syndrome was exacerbated. At 8 months old, urgent Senning operation was performed to improve desaturation. The patient was discharged at 20 post operative day. We conclude that Senning operation can be feasible operation in such a complicated case.

Analysis of T cell receptor Vbeta diversity in peripheral CD4 and CD8 T lymphocytes in patients with autoimmune thyroid diseases

Autoimmune thyroid diseases are characterized by intrathyroidal infiltration of CD4(+) and CD8(+) T lymphocytes reactive to self-thyroid antigens. Early studies analysing T cell receptor (TCR) Valpha gene usage have shown oligoclonal expansion of intrathyroidal T lymphocytes but not peripheral blood T cells. However, TCR Vbeta diversity of the isolated CD4(+) and CD8(+) T cell compartments in the peripheral blood has not been characterized fully in these patients. We performed complementarity-determining region 3 (CDR3) spectratyping as well as flow cytometric analysis for the TCR Vbeta repertoire in peripheral CD4(+) and CD8(+) T cells from 13 patients with Graves' disease and 17 patients with Hashimoto's thyroiditis. Polyclonal TCR Vbeta repertoire was demonstrated by flow cytometry in both diseases. In contrast, CDR3 spectratyping showed significantly higher skewing of TCR Vbeta in peripheral CD8(+) T cells but not CD4(+) T cells among patients with Hashimoto's thyroiditis compared with healthy adults. We found trends towards a more skewed CDR3 size distribution in those patients having disease longer than 5 years and requiring thyroid hormone replacement. Patients with Graves' disease exhibited no skewing both in CD4(+) and CD8(+) T cells. These findings indicate that clonal expansion of CD8(+) T cells in Hashimoto's thyroiditis can be detected in peripheral blood and may support the role of CD8(+) T cells in cell-mediated autoimmune attacks on the thyroid gland in Hashimoto's thyroiditis.

Two patterns of opacity in corneal dystrophy caused by the homozygous BIG-H3 R124H mutation

PURPOSE

To investigate the opacity pattern in corneas with an Arg124His (R124H) homozygous mutation of the BIG-H3 gene.

METHODS

Slit-lamp examination was performed on eight patients with corneal dystrophy resulting from a genetically confirmed BIG-H3 R124H homozygous mutation. The birthplace of each patient also was determined.

RESULTS

Slit-lamp examination disclosed two types of opacity patterns in corneas with the BIG-H3 R124H homozygous mutation. Type I (n = 4) is a spot-like opacity present in the anterior stroma in which the lesions are confluent. Type I is the same pattern that previous reports have shown to be caused by the BIG-H3 R124H homozygous mutation. The type II corneal opacity pattern (n = 4) is a reticular opacity in the anterior stroma with round translucent spaces. Type II opacity has not been reported previously in association with any corneal dystrophy. The patients with the type I opacity do not share a common birthplace; however, interestingly, the patients with the type II opacity traced their origin to Tottori prefecture in western Japan.

CONCLUSION

The BIG-H3 homozygous R124H mutation induces the development of two distinct patterns of corneal opacity, the recognition of which can establish an accurate diagnosis of corneal dystrophy caused by the homozygous BIG-H3 R124H mutation independent of genetic analysis. In addition, genetic factors or circumstantial influences other than the gene responsible for the corneal dystrophy may influence the pattern of corneal opacity.

Prolonged high intermittent positive-pressure ventilation induces airway remodeling and reactivity in young rats

We postulated that prolonged exposure to intermittent positive-pressure ventilation (IPPV) with high pressure (HIPPV) alone without hyperoxia promotes the development of airway hyperresponsiveness and remodeling. To test this hypothesis, young rats were ventilated under halothane anesthesia with HIPPV (maximum inspiratory pressure at 32-35 cmH2O in 70% nitrous oxide and 30% O2) for 3.5-4 h daily for 6 days. Control rats were ventilated with low IPPV (maximum inspiratory pressure < 13 cmH2O) during the same time period with the same gas mixture. With the use of tracheal rings isolated from these rats and a setup in tissue baths, contractile responses to carbachol (10(-6) to 10(-2) mM), 5-hydroxytryptamine (5-HT; 10(-9) to 10(-5) mM) and KCl (1-100 mM) were examined isometrically. In tracheal rings from HIPPV rats compared with low-pressure IPPV rats, the concentration tension curves showed a significantly enhanced response to all agonists (P < 0.005). Sensitivity to carbachol, 5-HT, and KCl was also significantly increased (P < 0.05) compared with control rats as evidenced by decreases in EC50. Maximum tension (reactivity) to 5-HT and KCl in the HIPPV group increased significantly (P < 0.05), and there was a trend (P = 0.07) toward increased reactivity to carbachol in this group as well. Histological examinations of tracheal rings demonstrated epithelial squamous metaplasia in the HIPPV group. Morphometric studies demonstrated tracheal smooth muscle thickening (P < 0.05) without changes in the thickness of the mucosa or the lamina propria. When contractile responses were normalized for the smooth muscle cross-sectional area (i.e., stress), reactivity to all contractile agents was reduced, whereas reactivity to 5-HT still demonstrated significant increase (P < 0.005). Sensitivity of tracheal segments to all three agents was not affected by this normalization. These findings suggest that prolonged exposure to HIPPV without hyperoxia and the resultant overdistension of lung tissues (volutrauma) induced airway remodeling and airway hyperreactivity.

Heterologous expression, purification, and properties of diol dehydratase, an adenosylcobalamin-dependent enzyme of Klebsiella oxytoca

Recombinant adenosylcobalamin-dependent diol dehydratase of Klebsiella oxytoca overexpressed in Escherichia coli was purified to homogeneity. The enzyme has a low solubility and was extracted from the crude membrane fraction with 1% Brij 35 in a high recovery. Subsequent chromatography on DEAE-cellulose resulted in 4.9-fold purification of the enzyme in an overall yield of 65%. The enzyme thus obtained showed specific activity comparable to that of the wild-type enzyme of K. oxytoca. The apparent molecular weight determined by nondenaturing gel electrophoresis on a gradient gel was 220,000. The enzyme consists of equimolar amounts of the three subunits with apparent Mr of 60,000 (alpha), 30,000 (beta), and 19,000 (gamma). Therefore, the subunit structure of the enzyme is most likely alpha2beta2gamma2. The recombinant enzyme was also separated into components F and S upon DEAE-cellulose chromatography in the absence of substrate. Components F and S were identified as the beta subunit and alpha2gamma2 complex, respectively. Apparent Km for adenosylcobalamin, 1,2-propanediol, glycerol, and 1,2-ethanediol were 0.83 microM, 0.08 mM, 0.73 mM, and 0.56 mM, respectively. The three genes encoding the subunits of diol dehydratase were overexpressed individually or in various combinations in Escherichia coli. The alpha and gamma subunits mutually required each other for correct folding forming the soluble, active alpha2gamma2 complex (component S). Expression of the beta subunit in a soluble, active form (component F) was promoted by coexpression with both the alpha and gamma subunits, probably by coexistence with component S. These lines of evidence indicate that each subunit mutually affects the folding of the others in this heterooligomer enzyme.

Temporal bone histopathologic findings of Waardenburg's syndrome: a case report

A histopathological study of the temporal bones of a 3-year-old black girl who had bilateral deafness associated with Waardenburg's syndrome type II showed a similar pattern of pathology in both ears. The most striking findings were an absence of pigmentation in the inner ear and cochleosaccular abnormality. This is, to our knowledge, only the third report on human temporal bone histopathology in Waardenburg's syndrome and the first report of such a case with absence of pigment (melanin) in the inner ear. A possible association of hearing loss with absence of inner ear pigment in this case is discussed.

Experimental otitis media evaluated by magnetic resonance imaging: an in vivo model

The use of magnetic resonance imaging in otitis media research is being explored in our laboratory. In this study, we present a new method for studying changes in the middle ear cleft due to an episode of induced otitis media in the chinchilla model. It uses gadolinium-diethylenetriamine pentaacetic acid, a magnetic resonance imaging contrast agent, to examine the uptake and washout characteristics of middle ear mucosa during an inflammatory episode. Parameters such as the time to maximum intensity of the mucosa and the washout rate of the contrast agent from the mucosa were significantly correlated to the duration of the infection.

Polycystic kidneys, pancreatic cysts, and cystadenomatous bile ducts in the oral-facial-digital syndrome type I

Oral-facial-digital syndrome type I is a group of X-linked dominant conditions, lethal in utero in male individuals. Internal anomalies are less well documented than are external findings. We report a case of typical phenotype and absent family history of kidney disease in a 15-year-old white girl (46,XX) who died of renal failure and massive cerebral hemorrhage. At necropsy, the kidneys were greatly enlarged but of fairly normal shape. The cortex was replaced by thin-walled spherical cysts, 0.5 to 2.0 cm in diameter; the majority of the smaller cysts were located deep in the cortex, and the medulla contained lesser numbers of larger cysts. No distal urinary tract obstruction was present. Microdissection revealed cysts and diverticula located in all segments of the nephrons and collecting ducts. Uninvolved nephrons showed diffuse hypertrophy. These findings were correlated with immunoperoxidase stains using peanut lectin, Lotus tetragonolobus agglutinin, antibodies to cytokeratins, stage-specific embryonic antigen-1, Tamm-Horsfall protein, and epithelial membrane antigen. Other visceral anomalies included biliary cystadenomatous proliferation in the liver and pancreatic cysts. The renal changes are similar to those of autosomal dominant (adult-type) polycystic disease.

Histologic study of eustachian tube cartilage with and without congenital anomalies: a preliminary study

We investigated histopathologically the development of the eustachian tube (ET) cartilage at a cellular level in individuals with and without congenital anomalies. Fourteen specimens were obtained from 14 individuals ranging in age from 24 weeks' gestation to 3 years who had cleft palate or trisomy 21 (Down) syndrome; the 49 specimens in the nonanomaly (control) group were from 49 individuals ranging from 26 weeks' gestation to 85 years of age. All temporal bone specimens included the ET and its accessory structures, and all were processed and stained with hematoxylin and eosin for histologic study in a routine manner. The number of cartilage cells in the midcartilaginous portion of the ET was determined by light microscopy. In all groups, cartilage cell density of the ET decreased with increasing age. However, cell density tended to be higher at all ages for individuals with cleft palate and microtia versus controls, and tended to be lower at all ages for individuals with Down syndrome.

Histopathologic study of otitis media in individuals with head and neck tumors

Five temporal bones, each including the eustachian tube, were obtained from five adults with advanced malignant tumors of the head and neck. The specimens were from the side on which the tumor had occurred. Otitis media had been detected clinically in two cases, and was detected histopathologically in the other three. We discuss the possibility that otitis media might have been caused by tumor invasion of the paratubal area, by postoperative inflammation in the nasopharynx, or by an inflammatory reaction of tubal structures to radiotherapy, or that these conditions may have coexisted.

Adrenal hemorrhage after liver transplantation

During orthotopic liver transplantation, ligation and division of the right adrenal vein during recipient hepatectomy may lead to hemorrhagic infarction and/or hematoma formation in the right adrenal gland. Findings in seven liver transplant recipients included initially echogenic or anechoic suprarenal masses on ultrasound scans and inhomogeneous but predominantly hypoattenuating masses on computed tomographic scans. In patients who survived for 4 months or longer, hematomas resolved as early as 20 days and persisted as long as 11 weeks. There was autopsy proof of adrenal hemorrhage in three cases. The adrenal hematomas in this series produced no massive hemorrhages, adrenal insufficiency, or other clinical manifestations. Adrenal hemorrhage after liver transplantation should be recognized and specifically documented, but a hematoma that remains stable in size can be left alone.

Temporal bone histopathologic findings in Alagille's syndrome

Six temporal bones obtained from four individuals with Alagille's syndrome, aged 4 months and 3, 6, and 7 years, were studied histopathologically. The external auditory canals and tympanic membranes were normal. Although the stapes, the interossicular joints, and the subarcuate fossae were slightly underdeveloped in the majority of cases, the other structures in the middle ear were almost normal. However, severe anomalies were observed in structures in the inner ear. In all cases, both the bony and membranous structures of the posterior semicircular canal were partially or totally absent, and, in three ears, those of the anterior semicircular canal were also partially absent; the lateral semicircular canal, however, was normal in all cases. The cochlea was observed to be shortened in only one case.

A staged laryngotracheal reconstruction using alloplast (Proplast) in the canine model

Standard laryngotracheal reconstructive procedures are constrained by the availability of grafting materials and the ability to repair large defects. Reconstruction utilizing alloplasts may be ideal, but previous results have generally been poor. We present a two-stage procedure using Proplast to reconstruct large laryngotracheal defects in 6 dogs. A custom-made Proplast implant was inserted into a strap muscle pocket and buccal mucosa was placed in the adjacent peritracheal tissue. The muscle-Proplast composite graft was rotated to repair a large defect (3.25 cm by 2.25 cm). All 6 dogs survived. Endoscopic and histologic studies over 12 months showed continued stabilization and maturation of the implant. We feel that Proplast may be used as an alternative to autograft for reconstructing large laryngotracheal defects when the procedure is staged to allow maximal fibrous ingrowth and the implant is protected from infection.

Syndromatic paucity of interlobular bile ducts: hepatic histopathology of the early and endstage liver

Morphologic findings of the liver in syndromatic paucity of intrahepatic bile ducts (SPIHBD) during infancy include paucity of interlobular bile ducts, features of "giant cell hepatitis," dilated lymphatics and veins in the portal tract, perisinusoidal fibrosis, and bile duct epithelial changes with a concentric layering of mesenchymal cells around bile ducts reminiscent of renal dysplasia. The latter change is characteristic of SPIHBD. Although the disease is characterized by paucity of bile ducts, morphometric studies show paucity of interlobular bile ducts in less than half of the patients during infancy. Reduced numbers of portal tracts and increased percentage of portal tracts devoid of bile ducts are more constant findings. It was impossible to predict from the early biopsy which patients would develop more severe portal fibrosis. Later in the disease portal fibrosis is variable and unevenly distributed, being more severe near the hilum regardless of the prior performance of a Kasai-type operation or the state of patency of the extrahepatic bile ducts. Hypoplasia of the extrahepatic bile ducts is the usual finding in SPIHBD, but if atresia of extrahepatic bile ducts is associated with intrahepatic paucity of bile ducts, the hepatic histopathology is that of PIHBD. Recognition of PIHBD would avoid unwarranted surgical procedures.