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L Hartung

Publications and source records attributed to L Hartung.

9 recordsLinked to original sources
PubMed1995

HLA-B27 screening by flow cytometry.

A flow cytometric assay for lymphocyte HLA-B27 expression using a two-color direct immunofluorescent assay was compared to traditional microlymphocytotoxicity testing on 209 clinical samples. For the flow cytometric assay, whole blood was mixed with a monoclonal anti-B27 conjugated to fluorescein-isothiocyanate (FITC) and anti-CD3 conjugated to phycoerythrin (PE). The samples were analyzed with flow cytometry by gating on CD3 positive events and anti-B27 staining intensity was evaluated as median channel fluorescence of the histogram peak. The median channel fluorescence was least with B27 negative and B7 negative samples (84 +/- 17), intermediate with samples that were B27 negative but B7 positive (118 +/- 13), and greatest with samples that were B27 positive (155 +/- 13). In addition to cross-reactivity with the B7 antigen (n = 38), the monoclonal anti-B27 cross-reacted with HLA-B37 positive samples (n = 3) and HLA-B39 positive samples (n = 3). Using a median channel fluorescence cutoff of 136, 39 of the 40 B27 positive samples gave positive results in the flow cytometric assay for a sensitivity of 97.6%. The specificity was 95.9% with 7 false positives of 169 B27 negative samples. The flow cytometric HLA-B27 assay is a convenient, useful screening test. For greatest specificity, samples positive by flow cytometry should be confirmed by conventional microlymphocytotoxicity or by use of other monoclonal antibodies directed against B27.

Flow Cytometry↗
PubMed1993

Prevention of adverse clinical outcome by monitoring of cardiac transplant patients for murine monoclonal CD3 antibody (OKT3) sensitization.

We have previously reported that patients sensitized to murine monoclonal CD3 antibody (OKT3) and maintained on such therapy for induction of immunosuppression have a high mortality and/or allograft loss. In this follow-up study, we retrospectively reviewed all patients routinely and serially monitored by flow cytometry for plasma levels of OKT3 during a 21-month period beginning 1/90. A total of 112 patients were monitored during this period. We retrospectively tabulated the incidence of OKT3 sensitization, rejection pattern and impact on survival of withdrawal of OKT3 at the time of sensitization as compared with the previous study in which withdrawal was not done. Nine patients were excluded from analysis because of withdrawal for reasons other than sensitization: cytokine encephalopathy, infection, postoperative complications, or severe rejection. Twelve patients had OKT3 therapy aborted because of failure to achieve steady-state OKT3 levels or because of decline in levels while on therapy. These patients were thus defined as being sensitized to OKT3. No patient was aborted because of return of CD3 cells in the blood. Only one of the 12 patients sensitized to OKT3 died. Of 91 patients with steady-state OKT3 levels, 6 had high plasma levels (> 1000 ng/ml) and 6 had low plasma levels (< 500 ng/ml). None of these patients had OKT3 therapy aborted and all are alive. Twelve of these 91 patients had successful retreatment with OKT3 for refractory rejection, indicating that absence of sensitization on induction predicts safety of retreatment with OKT3. We also examined the frequency of associated human antimouse antibody (HAMA) production using the blocking assay modified from Jaffers and Mayes. Only the sensitized patients exhibited a significant association with HAMA production (6/7 tested, P = 0.05) Classification of the rejection pattern of the sensitized patients confirmed our previous results: eight of 12 had vascular rejection and 4/12 had mixed rejection. These patterns were prospectively determined. We conclude that serial monitoring of patients for plasma levels of OKT3 is an effective strategy to prevent adverse outcomes of induction with this agent.

Graft Rejection↗