Indirect immunofluorescence (IIF) of normal washed peripheral blood cells to demonstrate antineutrophil cytoplasmic antibodies (ANCA)

Detection of Anti-neutrophil Cytoplasmic Antibodies (ANCA) by Indirect Immunofluorescence

The eventual presence of anti-neutrophil cytoplasmic antibodies (ANCA) can initially be screened with indirect immunofluorescence (IIF). The majority of laboratories that facilitate ANCA testing use commercial kits. Although in-house assays are not encouraged in routine clinical laboratories, knowledge on the methodological aspects of the assay remains of importance. These aspects include choice of substrate, choice of fixative, staining procedure, and interpretation procedure. In this paper details on the methodology are provided and discussed in the context of the clinical application.

A reliable Raman-spectroscopy-based approach for diagnosis, classification and follow-up of B-cell acute lymphoblastic leukemia

Acute lymphoblastic leukemia type B (B-ALL) is a neoplastic disorder that shows high mortality rates due to immature lymphocyte B-cell proliferation. B-ALL diagnosis requires identification and classification of the leukemia cells. Here, we demonstrate the use of Raman spectroscopy to discriminate normal lymphocytic B-cells from three different B-leukemia transformed cell lines (i.e., RS4;11, REH, MN60 cells) based on their biochemical features. In combination with immunofluorescence and Western blotting, we show that these Raman markers reflect the relative changes in the potential biological markers from cell surface antigens, cytoplasmic proteins, and DNA content and correlate with the lymphoblastic B-cell maturation/differentiation stages. Our study demonstrates the potential of this technique for classification of B-leukemia cells into the different differentiation/maturation stages, as well as for the identification of key biochemical changes under chemotherapeutic treatments. Finally, preliminary results from clinical samples indicate high consistency of, and potential applications for, this Raman spectroscopy approach.

Antineutrophil cytoplasmic antibody (ANCA) testing of routine sera varies in different laboratories but concordance is greater for cytoplasmic fluorescence (C-ANCA) and myeloperoxidase specificity (MPO-ANCA)

Most laboratories screen for antineutrophil cytoplasmic antibodies (ANCA) with indirect immunofluorescence (IIF) and confirm cytoplasmic (C-ANCA) and perinuclear (P-ANCA) staining with ELISAs for proteinase 3 (PR3) and myeloperoxidase (MPO) specificities. This study determined the concordance of ANCA test results from 48 diagnostic laboratories participating in a national Quality Assurance programme, that used different assays and methods and varied in expertise. Laboratories were circulated with a questionnaire about their techniques, and provided with 24 sera for testing over a 30 month period. Results for individual sera were compared with the 'observed consensus' found in more than 50% of laboratories. The 23 laboratories (48%) that responded to the questionnaire used 5 different IIF substrates and 11 ELISAs, and differed in other aspects of testing. Concordance for ANCA test results was greater for IIF-positive (n=22, median 96%, range 68%-100%) than an IIF-negative serum (median 64%); for C-ANCA (n=8, median 89%, range 66-100%) rather than P-ANCA (n=10, median 76%, range 52-88%); for MPO-ANCA (n=5, median 100%) rather than PR3-ANCA (n=7, median 89%, range 82-100%); and for strongly-positive (n=2, median 97%, range 96-97%) rather than low positive PR3-ANCA (n=4, median 80%, range 74-86%). Concordance for test results might be improved with further standardisation of testing methodologies.

Neutrophil functions of patients with vasculitis related to myeloperoxidase-specific anti-neutrophil antibody

Neutrophils are hypothesized to cause tissue damage resulting in the development of vasculitis and glomerulonephritis, although they are known to primarily take part in host defense functions. The infiltration of inflammatory cells. notably neutrophils and macrophages, is observed in the progression of vasculitis. Neutrophils with activated status and anti-neutrophil cytoplasmic antibodies (ANCAs), especially myeloperoxidase-specific (MPO)-ANCA, have been implicated in the development of vasculitis. The target molecule of MPG-ANCA is a lysosomal enzyme MPO that usually acts to kill bacteria, viruses, and fungi and that causes damage to the tissue due to the toxicity of its product, hypochlorite (OCl-). To elucidate the role of MPO-ANCA in the progression of vasculitis, a set of MPO-peptide fragments has been developed, and the corresponding epitope site for the specific monoclonal and/or oligoclonal antibody resulting in vasculitis has been determined. Recently some mouse models have been used for analyzing the correlation between MPO and MPO-ANCA in relation to damage of blood vessels followed by the development of vasculitis. This review focuses on the role of activated neutrophils in the development of vasculitis associated with MPO-ANCA and the target molecules of ANCA. In addition, the reactivities of ANCA and inflammatory cytokines involving leukocyte-derived chemotaxin 2 (LECT2) are also discussed.