Abnormal respiratory cilia in non-syndromic Leber congenital amaurosis with CEP290 mutations.

BACKGROUND: Leber congenital amaurosis (LCA) is the earliest and most severe inherited retinal degeneration. Isolated forms of LCA frequently result from mutation of the CEP290 gene which is expressed in various ciliated tissues. METHODS: Seven LCA patients with CEP290 mutations were investigated to study otorhinolaryngologic phenotype and respiratory cilia. Nasal biopsies and brushing were performed to study cilia ultrastructure using transmission electron microscopy and ciliary beating using high-speed videomicroscopy, respectively. CEP290 expression in normal nasal epithelium was studied using real-time RT-PCR. RESULTS: When electron microscopy was feasible (5/7), high levels of respiratory cilia defects were detected. The main defects concerned dynein arms, central complex and/or peripheral microtubules. All patients had a rarefaction of ciliated cells and a variable proportion of short cilia. Frequent but moderate and heterogeneous clinical and ciliary beating abnormalities were found. CEP290 was highly expressed in the neural retina and nasal epithelial cells compared with other tissues. DISCUSSION: These data provide the first clear demonstration of respiratory cilia ultrastructural defects in LCA patients with CEP290 mutations. The frequency of these findings in LCA patients along with the high expression of CEP290 in nasal epithelium suggest that CEP290 has an important role in the proper development of both the respiratory ciliary structures and the connecting cilia of photoreceptors. The presence of respiratory symptoms in patients could represent additional clinical criteria to direct CEP290 genotyping of patients affected with the genetically heterogeneous cone-rod dystrophy subtype of LCA.

A 20-year experience of electron microscopy in the diagnosis of primary ciliary dyskinesia.

Transmission electron microscopy (TEM) analysis of ciliary ultrastructure is classically used for the diagnosis of primary ciliary dyskinesia (PCD). We report our extensive experience of TEM analysis in a large series of patients in order to evaluate its feasibility and results. TEM analysis performed in 1,149 patients with suspected PCD was retrospectively reviewed. Biopsies (1,450) were obtained from nasal (44%) or bronchial (56%) mucosa in children (66.5%) and adults (33.5%). TEM analysis was feasible in 71.4% of patients and showed a main defect suggestive of PCD in 29.9%. TEM was more feasible in adults than in children, regardless of the biopsy site. Main defects suggestive of PCD were found in 76.9% of patients with sinopulmonary symptoms and in only 0.4% of patients with isolated upper and 0.4% with isolated lower respiratory tract infections. The defect pattern was similar in children and adults, involving dynein arms (81.2%) or central complex (CC) (18.8%). Situs inversus was never observed in PCD patients with CC defect. Kartagener syndrome with normal ciliary ultrastructure was not an exceptional condition (10.2% of PCD). In conclusion, TEM analysis is feasible in most patients and is particularly useful for PCD diagnosis in cases of sinopulmonary syndrome of unknown origin.

Pulmonary alveolar proteinosis associated with Pneumocystis carinii. Ultrastructural identification in bronchoalveolar lavage in AIDS and immunocompromised non-AIDS patients.

Pneumocystis carinii (PC) has been recognized as frequently responsible for most opportunistic pulmonary infections occurring in immunocompromised AIDS and non-AIDS patients. Moreover, these patients can be considered at risk for secondary pulmonary alveolar proteinosis. Therefore, we have investigated the occurrence of associated secondary alveolar proteinosis and PC pneumonitis in AIDS and non-AIDS immunocompromised patients. In a series of 26 bronchoalveolar lavages (BAL) in patients with PC pneumonitis (19 AIDS and seven non-AIDS patients), we observed on light microscopy, in addition to the honeycombed material, areas of an extracellular material that had a different pattern which was suggestive of that described in alveolar proteinosis. A systematic ultrastructural study of these 26 BAL fluid samples demonstrated in each of them an accumulation of phospholipid surfactantlike extracellular material mixed or not with the PC cysts. In nine cases, the observation of lipoproteinaceous material on light microscopy and abundant phospholipid material with myelinlike and myelin tubular laminated structures on electron microscopy was highly suggestive of an associated pulmonary alveolar proteinosis (PAP). Such an accumulation of extracellular material was not observed in the 11 BAL fluid samples collected in immunocompromised patients (seven AIDS and four non-AIDS patients) without PC pneumonitis. These findings demonstrated a particular frequency of associated PAP with PC pneumonitis. These results raise important questions concerning (1) the consequence of such an alveolar accumulation of lipoproteinaceous material on the clinical status and prognosis of the pneumonitis, and (2) the mechanisms responsible for this accumulation.