Table 3.
Correlations Between C3/EDTA Ratio (IFA and ELISA) and Outcome Measures
| Outcome | Correlation with C3/EDTA ratio (IFA) | Correlation with C3/EDTA ratio (ELISA) |
| INCAT sensory sum score (n = 101) | NS (rs = 0.04, p = 0.71) | NS (rs = 0.12, p = 0.29) |
| Anti-MAG titer ≥10,000 BTU (n = 63) | NS (rs = −0.03, p = 0.81) | NS (rs = 0.01, p = 0.95) |
| Anti-MAG titer <10,000 BTU (n = 38) | NS (rs = −0.15, p = 0.48) | NS (rs = 0.07, p = 0.72) |
| Anti-MAG titer ≥10,000 BTU and distal demyelination (n = 40) | NS (rs = −0.04, p = 0.82) | NS (rs = 0.07, p = 0.70) |
| Anti-MAG titer ≥10,000 BTU and tremor (n = 31) | NS (rs = −0.18, p = 0.41) | NS (rs = −0.02, p = 0.91) |
| Anti-MAG titer ≥10,000 BTU and no tremor (n = 25) | NS (rs = −0.10, p = 0.69) | NS (rs = −0.22, p = 0.37) |
| Anti-MAG titer ≥10,000 BTU and response after IVIG (n = 7) | NS (rs = −0.43, p = 0.42) | NS (rs = −0.71, p = 0.14) |
| Anti-MAG titer ≥10,000 BTU and no response after IVIG (n = 12) | NS (rs = −0.08, p = 0.83) | NS (rs = −0.09, p = 0.81) |
| Anti-MAG titer ≥10,000 BTU and response after rituximab (n = 16) | NS (rs = 0.39, p = 0.24) | NS (rs = −0.01, p = 0.98) |
| Anti-MAG titer ≥10,000 BTU and no response after rituximab (n = 24) | NS (rs = −0.03, p = 0.92) | NS (rs = −0.18, p = 0.50) |
| iRODS centile sum score | NS (rs = −0.02, p = 0.84) | NS (rs = −0.01, p = 0.89) |
| Anti-MAG titer ≥10,000 BTU (n = 63) | NS (rs = −0.06, p = 0.68) | NS (rs = −0.08, p = 0.56) |
| Anti-MAG titer <10,000 BTU (n = 38) | NS (rs = −0.16, p = 0.36) | NS (rs = 0.07, p = 0.68) |
| Anti-MAG titer ≥10,000 BTU and distal demyelination (n = 40) | NS (rs = −0.08, p = 0.65) | NS (rs = −0.01, p = 0.94) |
| Anti-MAG titer ≥10,000 BTU and tremor (n = 31) | NS (rs = −0.15, p = 0.44) | NS (rs = 0.16, p = 0.40) |
| Anti-MAG titer ≥10,000 BTU and no tremor (n = 25) | NS (rs = 0.20, p = 0.38) | NS (rs = −0.26, p = 0.25) |
| Anti-MAG titer ≥10,000 BTU and response after IVIG (n = 7) | NS (rs = −0.11, p = 0.81) | NS (rs = 0.24, p = 0.61) |
| Anti-MAG titer ≥10,000 BTU and no response after IVIG (n = 12) | NS (rs = −0.19, p = 0.56) | NS (rs = 0.14, p = 0.67) |
| Anti-MAG titer ≥10,000 BTU and response after rituximab (n = 16) | NS (rs = 0.01, p = 0.97) | NS (rs = −0.06, p = 0.83) |
| Anti-MAG titer ≥10,000 BTU and no response after rituximab (n = 24) | NS (rs = −0.02, p = 0.91) | NS (rs = −0.01, p = 0.97) |
| Ataxia sum score | NS (rs = 0.10, p = 0.35) | NS (rs = 0.20, p = 0.07) |
| Anti-MAG titer ≥10,000 BTU (n = 63) | NS (rs = 0.15, p = 0.28) | NS (rs = 0.21, p = 0.14) |
| Anti-MAG titer <10,000 BTU (n = 38) | NS (rs = 0.07, p = 0.69) | NS (rs = 0.21, p = 0.14) |
| Anti-MAG titer ≥10,000 BTU and distal demyelination (n = 40) | NS (rs = 0.13, p = 0.47) | NS (rs = 0.27, p = 0.12) |
| Anti-MAG titer ≥10,000 BTU and tremor (n = 31) | NS (rs = 0.14, p = 0.49) | NS (rs = 0.07, p = 0.73) |
| Anti-MAG titer ≥10,000 BTU and no tremor (n = 25) | NS (rs = −0.15, p = 0.54) | NS (rs = 0.20, p = 0.39) |
| Anti-MAG titer ≥10,000 BTU and response after IVIG (n = 7) | NS (rs = −0.16, p = 0.76) | NS (rs = −0.38, p = 0.46) |
| Anti-MAG titer ≥10,000 BTU and no response after IVIG (n = 12) | NS (rs = 0.54, p = 0.13) | NS (rs = −0.07, p = 0.88) |
| Anti-MAG titer ≥10,000 BTU and response after rituximab (n = 16) | NS (rs = 0.01, p = 0.97) | NS (rs = 0.62, p = 0.03) |
| Anti-MAG titer ≥10,000 BTU and no response after rituximab (n = 24) | NS (rs = 0.42, p = 0.07) | NS (rs = −0.17, p = 0.49) |
| MRC sum score (Rasch-transformed) | NS (rs = −0.09, p = 0.36) | NS (rs = −0.05, p = 0.60) |
| Anti-MAG titer ≥10,000 BTU (n = 63) | NS (rs = −0.14, p = 0.26) | NS (rs = −0.08, p = 0.55) |
| Anti-MAG titer <10,000 BTU (n = 38) | NS (rs = −0.05, p = 0.76) | NS (rs = 0.10, p = 0.53) |
| Anti-MAG titer ≥10,000 BTU and distal demyelination (n = 40) | NS (rs = −0.14, p = 0.41) | NS (rs = −0.15, p = 0.35) |
| Anti-MAG titer ≥10,000 BTU and tremor (n = 31) | NS (rs = −0.25, p = 0.17) | NS (rs = 0.11, p = 0.56) |
| Anti-MAG titer ≥10,000 BTU and no tremor (n = 25) | NS (rs = 0.12, p = 0.58) | NS (rs = −0.17, p = 0.42) |
| Anti-MAG titer ≥10,000 BTU and response after IVIG (n = 7) | NS (rs = −0.13, p = 0.78) | NS (rs = 0.56, p = 0.19) |
| Anti-MAG titer ≥10,000 BTU and no response after IVIG (n = 12) | NS (rs = 0.02, p = 0.96) | NS (rs = −0.30, p = 0.34) |
| Anti-MAG titer ≥10,000 BTU and response after rituximab (n = 16) | NS (rs = −0.36, p = 0.17) | NS (rs = −0.39, p = 0.13) |
| Anti-MAG titer ≥10,000 BTU and no response after rituximab (n = 24) | NS (rs = 0.04, p = 0.85) | NS (rs = −0.02, p = 0.93) |
| 10-meter walk test | NS (rs = 0.04, p = 0.69) | NS (rs = 0.14, p = 0.17) |
| Anti-MAG titer ≥10,000 BTU (n = 63) | NS (rs = −0.05, p = 0.70) | NS (rs = 0.05, p = 0.69) |
| Anti-MAG titer <10,000 BTU (n = 38) | NS (rs = 0.02, p = 0.92) | NS (rs = 0.24, p = 0.18) |
| Anti-MAG titer ≥10,000 BTU and distal demyelination (n = 40) | NS (rs = 0.00, p = 0.99) | NS (rs = 0.00, p = 0.99) |
| Anti-MAG titer ≥10,000 BTU and tremor (n = 31) | NS (rs = −0.11, p = 0.57) | NS (rs = 0.03, p = 0.89) |
| Anti-MAG titer ≥10,000 BTU and no tremor (n = 25) | NS (rs = −0.14, p = 0.19) | NS (rs = 0.01, p = 0.98) |
| Anti-MAG titer ≥10,000 BTU and response after IVIG (n = 7) | NS (rs = 0.06, p = 0.89) | NS (rs = −0.09, p = 0.85) |
| Anti-MAG titer ≥10,000 BTU and no response after IVIG (n = 12) | NS (rs = 0.48, p = 0.16) | NS (rs = 0.28, p = 0.43) |
| Anti-MAG titer ≥10,000 BTU and response after rituximab (n = 16) | NS (rs = 0.30, p = 0.26) | NS (rs = 0.33, p = 0.21) |
| Anti-MAG titer ≥10,000 BTU and no response after rituximab (n = 24) | NS (rs = −0.18, p = 0.44) | NS (rs = −0.08, p = 0.75) |
Abbreviations: BTU = Bühlmann titer units; IFA = immunofluorescence assay; MAG = myelin-associated glycoprotein; NS = not significant.
Analyses were performed with Spearman rank correlation tests.