European Respiratory Society guidelines for the diagnosis of primary ciliary dyskinesia

Abstract

The diagnosis of primary ciliary dyskinesia is often confirmed with standard, albeit complex and expensive, tests. In many cases, however, the diagnosis remains difficult despite the array of sophisticated diagnostic tests. There is no "gold standard" reference test. Hence, a Task Force supported by the European Respiratory Society has developed this guideline to provide evidence-based recommendations on diagnostic testing, especially in light of new developments in such tests, and the need for robust diagnoses of patients who might enter randomised controlled trials of treatments. The guideline is based on pre-defined questions relevant for clinical care, a systematic review of the literature, and assessment of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. It focuses on clinical presentation, nasal nitric oxide, analysis of ciliary beat frequency and pattern by high-speed video-microscopy analysis, transmission electron microscopy, genotyping and immunofluorescence. It then used a modified Delphi survey to develop an algorithm for the use of diagnostic tests to definitively confirm and exclude the diagnosis of primary ciliary dyskinesia; and to provide advice when the diagnosis was not conclusive. Finally, this guideline proposes a set of quality criteria for future research on the validity of diagnostic methods for primary ciliary dyskinesia.

Figure 1:

Diagram of normal ultrastructure of the ciliary axoneme in transverse section

Figure 2:

Electron microscopy images of PCD defects. A. Inner and outer dynein arm defect, B. Outer dynein arm defect, C. Inner dynein arm and microtubular disarrangement, D. central pair and transposition defect

Figure 3.

Immunofluorescence microscopy can be used to identify structural defects of motile cilia and to aid diagnosis of PCD. Antibodies directed against the outer dynein arm heavy chain DNAH5 (red, A) can be used to detect outer dynein arm defects caused by various genetic defects. Antibodies against DNAH11 (green, B) can detect DNAH11 loss-of function mutations that cause PCD with normal ultrastructure. The antibodies directed against GAS8 (red, C) can identify isolated defects of the nexin-dynein regulatory complex (C). Antibodies against CCDC39 (red, D) are used to detect defects of the 96nm axonemal ruler (D) caused by CCDC39 or CCDC40 mutations. Anti- RSPH9 antibodies (red, E) can be used to identify various defects of the radial spoke head complex (E). Normal localisation of ciliary components is shown by co-localisation (yellow color) with ciliary axonemal markers such as acetylated tubulin (green in A,D,E), alpha/beta tubulin (red in B) or unaffected ciliary components (i.e. DNAH5, green in C). In contrast, absence of structural components involved in ciliary motility is shown by absence of the protein in mutant cells (lower panels in A-E). Nuclei are shown in blue. Scale bars represent 10µm.

Figure 4.

Following development of recommendations using the GRADE approach, a Delphi survey allowed us to propose a diagnostic algorithm for PCD. Not all patients need to go through all steps. Please see the text for details of the implications of each diagnostic outcome (positive, highly likely and highly unlikely), as well as the consequences for the many patients who will continue to have an inconclusive outcome using currently available diagnostic tests. Patients with uncertain outcomes should be reconsidered for further testing as advances in diagnostic tests are made.