[Report of initial experiences in establishing a regional multicenter evaluation of lymphocyte typing with flow cytometry]. / Bericht über erste Erfahrungen bei der Etablierung eines regionalen Rundversuches von Lymphozytentypisierung mittels Flowzytometrie.

Participation in a multicenter evaluation of flowcytometric investigations is the only possibility of providing external quality control. Up to now nine different laboratories have taken part in this program, measuring two samples of fresh EDTA blood according to a recommended antibody panel. The choice of antibodies was intended to reach a standardized immune status. Three different types of flowcytometers were used. All results were expressed in lymphocyte subset percentages and in absolute values. The coefficient of variation of each lymphocyte subpopulation was used for interpretation of the results of all working groups, as well as the control measurement. The results of the control measurement already showed that there was a difference between the obtainable coefficient of variation for the different subpopulations. In the case of CD3, CD4 and CD8 positive lymphocytes the relative percentages of the total group gave values far below 10%. The coefficients of variation of the activated T-lymphocytes or the cytotoxic T-cells, as well as of the absolute values were definitely higher. Already after the second multicenter evaluation the achieved results showed positive aspects such as improvements of the outcome, advancement of the user contacts, cooperation and impulses by discussing interesting problems.

[The enzyme-linked immunosorbent assay technic in syphilis serology (report on experiences)]. / Die ELISA-Technik in der Syphilisserologie (Erfahrungsbericht).

A serological study with an enzyme-linked immunosorbent assay using the axial filament of Treponema phagedenis biotype Reiter as antigen was performed on 1899 sera to evaluate the sensitivity and specificity. The sensitivity as compared with the fluorescent treponemal antibody-absorption test (FTA-ABS) and the automated microhaemagglutination assay with Treponema pallidum antigen ( AMHA -TP) was 94.6% and 93.1%, respectively. The specificity was 98.5% compared to both assays. Furthermore, preliminary results for the determination of IgM antibodies with the same antigen are presented. All procedures including dispensing, washing, optical reading and evaluation of results were performed automatically using a newly-developed ELISA processor connected with an electronic surveillance and control device.

[The SPHA technic (solid phase hemadsorption) in syphilis serology. A year's experience in routine laboratory procedure]. / Die SPHA-Technik (Solid-Phase-Hämadsorption) in der Syphilisserologie. Einjährige Erfahrung im Routinebetries.

The first results in routine syphilis serology with the new solid-phase hemadsorption assay (SPHA) are presented. Sera (63019) were screened by the VDRL test and by the automated hemagglutination assay with Treponema pallidum antigen (AMHA-TP). Samples reactive to one or both of these tests were further examined by the FTA-ABS test, the IgM-FTA-ABS test, the 19S IgM-FTA-ABS test (IgM-FTA-ABS test performed with the 19S fraction of the serum after gelfiltration) and the IgM-SPHA test. IgM-SPHA reactive sera derived from patients who were in the early stage or in the phase of latency (of undefinable duration), further from patients with active neurosyphilis and from 26 patients after reinfection. Erroneous results in the IgM-FTA-ABS test caused by a competitive inhibition of IgM by IgG can be eliminated by the IgM-SPHA method. The agreement between 19S IgM-FTA-ABS test and IgM-SPHA test is above 96.3%. As compared to the fluorescence test, the IgM-SPHA test is simpler to perform and can be easily automated.

Diagnosis of neurosyphilis by examination of the cerebrospinal fluid.

Thirty-six patients with reactive results in the cerebrospinal fluid to the Treponema pallidum haemagglutination assay (CSF-TPHA) were investigated by further serological tests for confirmation of active neurosyphilis. The results of the TPHA and fluorescent treponemal antibody tests were reactive in all CSF samples from patients with acute untreated neurosyphilis and from most patients with late latent syphilis but no signs of involvement of the central nervous system. The demonstration of 19S-IgM antibodies against Treponema pallidum in the CSF was a better indication of activity of the disease than the Venereal Disease Research Laboratory test. Ten of 11 patients with untreated acute neurosyphilis had reactive results in the solid-phase haemadsorption test for CSF-IgM (CSF-IgM-SPHA test). The TPHA index, which relates the CSF-TPHA titre to the albumin quotient and thus excludes errors from disturbed function of the blood-brain barrier, was above 100 in all but one of the patients with acute neurosyphilis but below 100 after treatment. Patients with late latent syphilis and without CNS signs had TPHA indices below 5. Thus a nonreactive CSF-TPHA test result excludes neurosyphilis but reactive CSF-IgM-SPHA results and TPHA indices above 100 strongly indicative active disease.