Demonstration by flow cytometry of the numbers of residual white blood cells and platelets in filtered red blood cell concentrates and plasma preparations.

Background And Objectives: New-generation polyester filters provide significant depletion of white blood cells (WBC) and platelets (PLT) in filtered red blood cell concentrates (FRCC) and in filtered plasma preparations (FP). The aim of this study was to elaborate a sensitive flow cytometric method for monitoring residual WBC and PLT in FRCC and FP.

Materials And Methods: We determined the number of WBC in 500 microliters FRCC of FP using 50 microliters of a combination of monoclonal antibodies (MAB) against CD45 (FITC labeled) and CD19 (PE labeled).

Evaluation of four monoclonal antibodies against HLA-B27 for their reliability in HLA-B27 typing with flow cytometry (FC): comparison with the classic microlymphocytotoxic test (MLCT).

Typing for HLA-B27 by serological methods is routinely performed using the microlymphocytotoxic test (MLCT). Since monoclonal antibodies (MAB) against HLA-B27 are available, flow cytometry (FC), which requires less time than the MLCT has been developed as an alternative technique. The aim of the present study was to check the accuracy and reliability of this method using different MAB against HLA-B27 in comparison to MLCT (using polyclonal antibodies against HLA-B27 and cross-reacting specificities [CRS]).

Clinical and immunological aspects of autoantibodies to RA33/hnRNP-A/B proteins--a link between RA, SLE and MCTD.

Heterogeneous nuclear ribonucleoprotein (hnRNP) complexes are major constituents of the spliceosome. They are composed of approximately 30 different proteins which can bind to nascent pre-mRNA. Among these, the hnRNP-A/B proteins form a subgroup of highly related proteins consisting of two adjacent RNA binding domains (RBD) within the N-terminal parts, whereas the C-terminal halves contain almost 50% glycine residues.

Soluble receptors for tumor necrosis factor and interleukin-2 in serum and synovial fluid of patients with rheumatoid arthritis, reactive arthritis and osteoarthritis.

Objective: To compare levels of soluble tumor necrosis factor receptor (TNF-R) and soluble interleukin 2 receptor (sIL-2R) in sera and synovial fluids (SF) of patients with rheumatoid arthritis (RA), reactive arthritis (ReA), and osteoarthritis (OA) in order to investigate the usefulness of soluble cytokine receptors for differentiation diagnosis and their involvement in the pathophysiology of rheumatic diseases.

Methods: Soluble TNF-R (55 kDa), sIL-2R, and TNF-alpha were measured by ELISA in sera and SF of patients with RA, ReA, and OA and correlated with serological and clinical disease activity variables.

Results: Serum TNF-R was significantly (p < 0.

Standardization of the flow cytometric determination of HLA class I antigens, 'platelet-specific' glycoproteins and activation markers.

Flow cytometry (FC) provides a reproducible investigation of cell surface antigens on platelets. The aim of this study was to elaborate appropriate protocols and to compare them with other techniques that have already been published. (1) Venipuncture with tubes containing citrate was better for the preservation of the antigenicity than using ACD tubes.

Anti-RA33 autoantibodies may recognize epitopes in the N-terminal region of hnRNP-A2 (RA33).

The nuclear autoantigen RA33, which is identical to the A2 protein of the heterogeneous nuclear ribonucleoprotein (hnRNP-A2), is a nucleic acid binding protein of 341 amino acids. The N-terminal part contains two RNA binding domains whereas the C-terminal part consists of a long glycine-rich region starting around amino acid 192. Autoantibodies to hnRNP-A2/RA33 can be detected in 20-40% of sera from RA, SLE and MCTD patients.

Influence of chloroquine or acid treatment of human platelets on the antigenicity of HLA and the 'thrombocyte-specific' glycoproteins Ia/IIa, IIb, and IIb/IIIa.

The influence of treatment of platelets with citrate buffer (pH 7.2), chloroquine, or citric acid at pH 3 on the expression of HLA class I antigens and 'thrombocyte-specific' glycoproteins was investigated by means of flow cytometry. After treatment with citric acid at pH 3 and chloroquine, the expression of HLA class I was significantly reduced, while the density of the molecules GPIa/IIa, GPIIb, and GPIIb/IIIa (GP = glycoprotein) carrying 'thrombocyte-specific' antigens was not or only weakly decreased on the surface of the platelets.

Purification and partial sequencing of the nuclear autoantigen RA33 shows that it is indistinguishable from the A2 protein of the heterogeneous nuclear ribonucleoprotein complex.

RA33 is a nuclear autoantigen with an apparent molecular mass of 33 kD. Autoantibodies against RA33 are found in about 30% of sera from RA patients, but only occasionally in sera from patients with other connective tissue diseases. To characterize RA33, the antigen was purified from HeLa cell nuclear extracts to more than 90% homogeneity by affinity chromatography on heparin-Sepharose and by chromatofocusing.