Fatal outcomes in family transmission of Mycoplasma pneumoniae.

BACKGROUND: Mycoplasma pneumoniae continues to be a significant cause of community-acquired pneumonia and, on rare occasions, manifests as fulminant disease that leads to mortality, even in healthy individuals. METHODS: We conducted a retrospective study on members of a family who were quarantined by the Centers for Disease Control and Prevention in 2002 for respiratory failure and death of a 15-year-old brother (sibling 1) and a 13-year-old sister (sibling 2). Collected airway, cerebrospinal fluid (CSF), and serum samples from both deceased siblings and serum samples from both parents and the remaining 3 ill siblings (sibling 3-5) were tested using a range of diagnostic assays. Autopsy lung tissue samples from sibling 2 were also assessed using immunohistochemical and immunoelectron microscopic methods. RESULTS: Autopsy evaluation of sibling 1 revealed cerebral edema consistent with hypoxic ischemic encepatholopathy and pulmonary findings of bronchiolitis obliterans with organizing pneumonia (BOOP). Postmortem lung examination of sibling 2 revealed lymphoplasmacytic bronchiolitis with intraluminal purulent exudate, BOOP, and pulmonary edema. Results of diagnostic assays implicated the household transmission of M. pneumoniae among all 5 siblings and both parents. Further analysis of lung tissue from sibling 2 demonstrated the presence of M. pneumoniae organisms and community-acquired respiratory distress syndrome toxin. M. pneumoniae was cultured directly from sibling 2 autopsy lung tissue. CONCLUSION: Evidence is provided that M. pneumoniae was readily transmitted to all members of the household and that the resulting infections led to a spectrum of individual responses with variation in disease progression, including lymphoplasmacytic bronchiolitis, BOOP, and death.

Immunolocalization of E-cadherin in human head and neck cancer.

Loss of expression of the cell-cell adhesion molecule E-cadherin has been shown to have a potential role in the dedifferentiation and progression of many human malignancies. We applied immunohistochemical staining for E-cadherin to eight formalin-fixed, paraffin-embedded primary and matched metastatic human head and neck carcinomas. In tumors that contained both well-differentiated and poorly differentiated components, staining was notably reduced in the poorly differentiated cells. Staining was nearly identical or only slightly reduced in metastases compared to primary tumors. As found in previous reports, E-cadherin expression may be involved in the dedifferentiation of these tumors.

L3T4+ T cells regulate Abelson virus-induced lymphomagenesis.

To evaluate the role of T cells in regulation of lymphomagenesis, experiments were performed using Abelson murine leukemia virus (AMuLV). In vitro transformation of bone marrow target cells by this B lymphotropic retrovirus was inhibited by peripheral lymph node cells from naive mice. The inhibitory activity depended on Thy-1+ L3T4+ cells but did not require Lyt-2+ cells. In vivo depletion of L3T4+ T cells with a mAb (GK1.5) altered the course of AMuLV-induced lymphoma. L3T4 depletion of naturally resistant C57BL/6 mice resulted in dramatic susceptibility to lymphoma induction. Lymphoma cells from anti-L3T4-treated C57BL/6 mice infected with AMuLV displayed the B lineage transformation marker P1606C3. These studies reveal an important immunologic component of Abelson disease resistance involving L3T4+ T cells.

Immunohistochemical evaluation of E-cadherin and epidermal growth factor receptor in non-small cell lung cancer.

Enhanced expression of the epidermal growth factor receptor and loss of expression of the cell-cell adhesion molecule E-cadherin have each been implicated in the development and progression of a variety of human malignancies. There is some evidence for a correlation between the expression of these two genes and the possible influence of the E-cadherin gene product on the expression of epidermal growth factor receptor. We evaluated 33 matched primary and metastatic non-small cell lung cancer specimens using immunohistochemical staining. There was a statistically significant correlation between staining intensity for epidermal growth factor receptor and E-cadherin in the primary tumors (P = 0.017, by Spearman correlation test). No difference was noted between primary and metastatic disease for either gene product. Studies that include clinical data are needed to clarify the significance of these findings and to evaluate whether these markers will help predict prognosis in tumors.

Absence of a reservoir of Epstein-Barr virus (EBV) in normal tongue epithelium.

We examined human tongue epithelium and serum samples at autopsy for evidence of latent Epstein-Barr virus (EBV) infection. Although clinical serology revealed anti-EBV antibodies in most sera indicating past EBV infection, we found no Epstein-Barr nuclear antigen (EBNA)-coding sequences in tongue tissue by polymerase chain reaction (PCR), or Epstein-Barr-encoded RNA (EBER1) by in situ hybridization. Tongue epithelium does not appear to be a natural reservoir for latent EBV in immunocompetent hosts.