Table 3.
Clonality detection by IF, FLC, iFISH, IHC, and MFC in patients with amyloid light chain (AL) amyloidosis and underlying PC disorder
| IHC organ biopsy | IF serum | IF urine | FLC serum | iFISH BM PCs | IHC BM | MFC BM |
|---|---|---|---|---|---|---|
| κ, n = 12 | ||||||
| κ | 7 | 9 | 12 | – | 8 | 12 |
| Positive | – | – | – | 11 | – | – |
| Negative | 2 | 2 | 0 | 1 | 1 | 0 |
| n.o.s. | 2 | 1 | 0 | 0 | 0 | 0 |
| n.a. | 1 | 0 | 0 | 0 | 3 | 0 |
| λ, n = 40 | ||||||
| λ | 33 | 35 | 36 | – | 23 | 38 |
| Positive | – | – | – | 37 | – | – |
| Negative | 6 | 4 | 4 | 2 | 3 | 2 |
| n.o.s. | 1 | 0 | 0 | 0 | 0 | 0 |
| n.a. | 0 | 1 | 0 | 1 | 14 | 0 |
| n.i., n = 9 | ||||||
| κ | 2 | 2 | 3 | – | 2 | 3 |
| λ | 4 | 5 | 5 | – | 1 | 6 |
| Positive | – | – | – | 9 | – | – |
| Negative | 3 | 2 | 1 | 0 | 1 | 0 |
| n.o.s. | 0 | 0 | 0 | 0 | 0 | 0 |
| n.a. | 0 | 0 | 0 | 0 | 5 | 0 |
We analyzed clonality in 61 patients with AL amyloidosis and underlying PC disorder. The light chain type of the amyloid was identified by organ biopsy IHC in 52 patients (12 κ and 40 λ). In nine cases, IHC of organ biopsy was not able to classify amyloid deposits or was not available. Six different methods of clonality detection are compared. Number of cases with a positive, negative, not otherwise specifiable, or not available results are shown. BM, bone marrow; FLC, light chain; IF, immunofixation; iFISH, interphase fluorescence in situ hybridization; IHC, immunohistochemistry; MFC, multicolor flow cytometry; n.a., not available; n.i., not identified; n.o.s., not otherwise specified; PC, plasma cell.