Table 3.
Autoantibodies, complement assays and genetic variants in the 5 C4NeF-positive patients
| Patient No. | Diagnosis | Date of Testing | C4NeF (ref <20%) | IFE (ref <7.5%) | C3NeF (C3CSA) (ref <20%) | C3NeF (C3CSAP) (ref <20%) | FHAA | FBAA | Hemolytic Assayf (ref <3%) | APFA (ref 50%~130%) | CH50 (ref 30~70 u/mL) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | C3 GN | 08/2013 | >100% | 14% | Neg | Neg | Pos (titer of 1:200) | Neg | normal | 0.4% | 7 |
| 2 | C3 GN | 01/2014 | >100% | 11% | Neg | Neg | Neg | Neg | 7% | 0.6% | 10 |
| 3 | C3 GN | 03/2013 | 53% | Neg | Neg | Neg | Neg | Neg | normal | 1.7% | <5 |
| 4 | DDD | 01/2012 | >100% | Neg | Neg | Neg | Neg | Neg | normal | 14% | 25 |
| 5 | C3 GN | 01/2013 | 81% | Neg | 67% | 46% | Neg | Neg | normal | 0 | 6 |
Note:Normal reference (ref) ranges are listed in parentheses of column headings
Abbreviations and definitions: C4NeF, C4 nephritic factor; IFE, immunofixation electrophoresis; C3NeF (C3CSA), C3 nephritic factor measured by C3 convertase stabilizing assay without properdin; C3NeF (C3CSAP), C3 nephritic factor measured by C3 convertase stabilizing assay with properdin; FHAA, factor H autoantibodies; FBAA, factor B autoantibodies; APFA, alternative pathway functional assay; Neg, negative; DDD, dense deposit disease; GN, glomerulonephritis; Pos, positive
Hemolytic assay using non-sensitized sheep erythrocytes
No genetic variants were detected by examining exons and intron-exon boundary junctions of multiple complement genes (C3, CFH, CFI, MCP, CFD, CFB, DGKE)