c1q-assay (c1q screen  (Thermo Fisher)

Journal: Journal of Thoracic Disease

Article Title: Approaching the sensitized lung patient: risk assessment for donor acceptance

doi: 10.21037/jtd-2021-21

Figure Lengend Snippet: Case #1: high cPRA/low titer/C1q-negative. Among Class I HLA antibodies, 46% of positive beads fall in the upper moderate range (4,001–8,000 MFI). The remainder is equally distributed (27% each) between the weak (1,000–2,000 MFI) and the low moderate (2,001–4,000 MFI) ranges. The Class II show virtually an even distribution of antibodies among the weak, low moderate and upper moderate categories, with only 4% of antibodies in the strong range (>8,000 MFI). At a 1:16 dilutions, all positive beads fall in the weak range and the C1q assay is negative. MFI, median fluorescence intensity.

Article Snippet: Undiluted positive sera were tested for the presence of complement-fixing antibodies using the modified Luminex-based single antigen beads C1q-assay (C1q Screen - One Lambda Thermo Fisher, West Hills, CA).

Techniques: Fluorescence

Journal: Journal of Thoracic Disease

Article Title: Approaching the sensitized lung patient: risk assessment for donor acceptance

doi: 10.21037/jtd-2021-21

Figure Lengend Snippet: Case #2: high cPRA/moderate titer/C1q-positive. (A) For Class I, 19% of antibodies are in the strong (>8,000 MFI) group, 42% fall in the upper moderate (4,001–8,000 MFI) range, 32% in the low moderate (2,001–4,000 MFI) range and only 6% were in the weak range (1,000–2,000 MFI). Similarly, on the Class II assay, 28% were strong (>8,000 MFI), 44% were in the upper-moderate range (4,001–8,000 MFI), 20% were in the low moderate range (2,001–4,000 MFI) while none exhibited weak reactivity (1,000–2,000 MFI). For both Classes, 1:16 dilution shows a shift into the weak range with about 55% of Class I positive beads and 50% of Class II positive beads in this category. As could be predicted, these antibodies are C1q positive for both Classes and distributed among all ranges. (B) Effect of PLEX and IVIG on IgG subclasses and C1q assay. Despite the relative MFI values of antibodies in the undiluted serum, changes in the subclasses composition of these antibodies following desensitization correlates with the C1q assay results. MFI, median fluorescence intensity; PLEX, plasma exchange; IVIG, intravenous immunoglobulin.

Article Snippet: Undiluted positive sera were tested for the presence of complement-fixing antibodies using the modified Luminex-based single antigen beads C1q-assay (C1q Screen - One Lambda Thermo Fisher, West Hills, CA).

Techniques: Ii Assay, Fluorescence

Journal: Journal of Thoracic Disease

Article Title: Approaching the sensitized lung patient: risk assessment for donor acceptance

doi: 10.21037/jtd-2021-21

Figure Lengend Snippet: Case #3: high cPRA/high titer/C1q-positive. The undiluted serum shows an almost even distribution of antibodies among the three groups of MFI ranges between 2001 to >8,000. At 1:64 dilution, positive beads remain almost evenly distributed in all ranges. As could be predicted, the C1q assay is positive and shows that 81% of the positive beads are in the >8,000 MFI range. Class II testing was negative. MFI, median fluorescence intensity.

Article Snippet: Undiluted positive sera were tested for the presence of complement-fixing antibodies using the modified Luminex-based single antigen beads C1q-assay (C1q Screen - One Lambda Thermo Fisher, West Hills, CA).

Techniques: Fluorescence

Journal: Journal of Thoracic Disease

Article Title: Approaching the sensitized lung patient: risk assessment for donor acceptance

doi: 10.21037/jtd-2021-21

Figure Lengend Snippet: Case #4: high cPRA/low titer/C1q-negative patients with antibody to a shared HLA epitope. (A) Positive beads distribution for a patient expressing an anti-Bw4 antibody. Despite the fact that 61% of beads in this serum fall in the >8,000 MFI category, the 1:16 dilution shows that 86% of beads have <2,001 MFI and all are C1q-negative. (B). Cell binding capabilities of the antibodies in this serum. A series of surrogate FCXM against mock donors with one target/cell (Aw4; Bw4/Bw6) or two targets/cell (Bw4/Bw4) were compared to a no target/cell surrogate donor (self-like, Bw6/Bw6 donor). FCXM against one- and two-target donor cells both resulted in a positive FCXM, as indicated by the channel shift observed with all but the self-like mock donor cells. MFI, median fluorescence intensity; FCXM, flow crossmatches.

Article Snippet: Undiluted positive sera were tested for the presence of complement-fixing antibodies using the modified Luminex-based single antigen beads C1q-assay (C1q Screen - One Lambda Thermo Fisher, West Hills, CA).

Techniques: Expressing, Binding Assay, Fluorescence

Journal: Journal of Thoracic Disease

Article Title: Approaching the sensitized lung patient: risk assessment for donor acceptance

doi: 10.21037/jtd-2021-21

Figure Lengend Snippet: Proposed testing strategy for allosensitized patients. Risk stratification and donor selection is determined by considering the antibody profile in combination with patient clinical status. For each mismatched HLA antigen of a potential donor, the antibody reactivity is evaluated for antibody titer (low-high) and C1q reactivity (negative-positive). MFI, median fluorescence intensity; DSA, donor-specific antibodies.

Article Snippet: Undiluted positive sera were tested for the presence of complement-fixing antibodies using the modified Luminex-based single antigen beads C1q-assay (C1q Screen - One Lambda Thermo Fisher, West Hills, CA).

Techniques: Selection, Fluorescence