02 August 2021
: Case report 
Acquired Thrombotic Thrombocytopenic Purpura Without Anti-ADAMTS13 Antibody Caused by Influenza A (H1N1) Virus Successfully Treated by Plasma Exchange: A Case Report
Challenging differential diagnosis, Diagnostic / therapeutic accidents, Management of emergency care, Rare disease, Educational Purpose (only if useful for a systematic review or synthesis)
Keisuke Kubo1ABDEF*, Tomohiro Abe
1ACDEF, Noriaki Kawano2B, Hidenobu Ochiai3ACEF
DOI: 10.12659/AJCR.932251
Am J Case Rep 2021; 22:e932251
Table 2. Laboratory findings at the diagnosis of TMA.
| Normal range | ||
|---|---|---|
| Haptoglobin (mg/L) | <100 | 300–2000 |
| ADAMTS13 activity (%)×FRETS-VWF73 assay | 65.4 | >70 |
| ADAMTS13 activity (%)× chromogenic act-ELISA assay | <0.5 | >70 |
| ADAMTS13 inhibitor (BU) | <0.4 | <0.4 |
| Anti-LPS-IgM antibody | Negative | Negative |
| Anti-HIT antibody (U/mL) | <0.6 | <1.0 |
| Anti-nuclear antibody | Negative | Negative |
| Anti-CL β2GP antibody (U/mL) | <1.2 | <3.5 |
| Anti-ds-DNA antibody (IU/mL) | <10 | <30 |
| Anti-RNP antibody (U) | <1.0 | <1.0 |
| Anti-scl-70 antibody (U) | <1.0 | <1.0 |
| Anti-SS-A antibody (U) | <1.0 | <1.0 |
| Anti-SS-B antibody(U) | <1.0 | <1.0 |
| PR3-ANCA (U) | <1.0 | <1.0 |
| MPO-ANCA (U) | <1.0 | <1.0 |
| C3 (g/L) | 1.08 | 75–175 |
| C4 (g/L) | 0.38 | 14–40 |
| CH50 (U/mL) | >60.0 | 30–75 |
| ADAMTS13 – a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13; ELISA – enzyme-linked immunosorbent assay; LPS – lipopolysaccharide; IgM – immunoglobulin M; HIT – heparin-induced thrombocytopenia; CL – cardiolipin; IgG – immunoglobulin G; Anti-CL β2GP – anti-cardiolipin antibody/β2-glycoprotein; ss – single-stranded; ds – double-stranded; RNP – ribonucleoprotein; scl-70 – topoisomerase-1; anti-SS-A – anti-Ro; anti-SS-B – anti-La; PR3-ANCA – anti-proteinase 3-antineutrophil cytoplasmic autoantibodies; MPO-ANCA – myeloperoxidase- antineutrophil cytoplasmic autoantibodies; C3 – complement 3; C4 – complement 4; CH50 – 50% hemolytic complement. | ||