Titers of IgG and IgM Antibodies to Ap Obtained by IFA in Transplant Donors and Patients Who Had Previously Been Screened for Lyme Antibody Stratified by C6 Peptide ELISA and Lyme Immunoblot Results
| Cohort . | Cohort Descr iption . | Ap Screen IgG Positive No (%) . | Ap IgG GMT . | Ap Screen IgM Positive No (%) . | Ap IgM GMT . | Analysis Groups . | OR (95% CI) . | P Valuea . |
|---|---|---|---|---|---|---|---|---|
| 1 | Transplant Donors | 3/77 (3.89) | NAb | 0/3 | 0 | 1 vs 7 | 5.9 (1.8–19.4) | .0003 |
| 2 | C6 Negative | 29/182 (15.93) | 83.24 | 1/29 (3.44) | 80 | 2 vs 1 | 4.0 (1.2–13.8) | .017 |
| 3 | Low C6 Positive | 8/28 (28.57) | 128 | 1/8 (12.5) | 20 | 3 vs 1 | 7.3 (1.8–29.6) | .007 |
| 4 | High C6 Positive | 12/39 (30.76) | 203.18 | 4/12 (56.56) | 56.56 | 4 vs 1 | 7.8 (2.1–29.6) | .001 |
| 5 | LIB IgM+/IgG− | 16/46 (34.78) | 378.06 | 13/16 (46.93) | 46.93 | 5 vs 1 | 8.9 (2.4–32.3) | .0003 |
| 6 | LIB IgG+ | 21/74 (28.37) | 301.93 | 11/21 (52.38) | 40 | 6 vs 1 | 7.2 (2.08–25.4) | .0005 |
| 7 | Tick-Exposed (C6 positive and negative) | 86/369 (23.30) | 178.12 | 30/86 (34.88) | 44.89 | NA | NA | NA |
| 8 | C6 Positive | 57/187 (30.48) | 262.30 | 29/57 (50.87) | 44.01 | 8 vs 2c | NA | P < .0001 |
| Cohort . | Cohort Descr iption . | Ap Screen IgG Positive No (%) . | Ap IgG GMT . | Ap Screen IgM Positive No (%) . | Ap IgM GMT . | Analysis Groups . | OR (95% CI) . | P Valuea . |
|---|---|---|---|---|---|---|---|---|
| 1 | Transplant Donors | 3/77 (3.89) | NAb | 0/3 | 0 | 1 vs 7 | 5.9 (1.8–19.4) | .0003 |
| 2 | C6 Negative | 29/182 (15.93) | 83.24 | 1/29 (3.44) | 80 | 2 vs 1 | 4.0 (1.2–13.8) | .017 |
| 3 | Low C6 Positive | 8/28 (28.57) | 128 | 1/8 (12.5) | 20 | 3 vs 1 | 7.3 (1.8–29.6) | .007 |
| 4 | High C6 Positive | 12/39 (30.76) | 203.18 | 4/12 (56.56) | 56.56 | 4 vs 1 | 7.8 (2.1–29.6) | .001 |
| 5 | LIB IgM+/IgG− | 16/46 (34.78) | 378.06 | 13/16 (46.93) | 46.93 | 5 vs 1 | 8.9 (2.4–32.3) | .0003 |
| 6 | LIB IgG+ | 21/74 (28.37) | 301.93 | 11/21 (52.38) | 40 | 6 vs 1 | 7.2 (2.08–25.4) | .0005 |
| 7 | Tick-Exposed (C6 positive and negative) | 86/369 (23.30) | 178.12 | 30/86 (34.88) | 44.89 | NA | NA | NA |
| 8 | C6 Positive | 57/187 (30.48) | 262.30 | 29/57 (50.87) | 44.01 | 8 vs 2c | NA | P < .0001 |
Abbreviations: AP, Anaplasma phagocytophilum; CI, confidence interval; ELISA, enzyme-linked immunosorbent assay; GMT, geometric mean titer; IFA, indirect fluorescent assay; Ig, immunoglobulin; LIB, Lyme immunoblot; NA, not applicable; OR, odds ratio.
*Ap IgM screening was only done for those sera with positive IgG screen results. GMTs were only calculated for those sera with positive screen results. The positivity cutoff for C6 peptide ELISA was 1.1, and the enhanced cutoff for low vs high was 4.
aFisher’s exact test (including OR with 95% CI) for Ap IgG result only. Results were considered statistically significant at P < .05.
bGiven the small number of screen-positive sera in this cohort, GMT was not calculated to avoid bias. Three sera in this cohort had titers of 64 (2) and 128, with negative IgM results suggesting past exposures to Ap.
cComparison of Ap IgG GMTs between cohorts 2 and 8 using Mann-Whitney U test showed statistically significant difference (P < .0001).
Titers of IgG and IgM Antibodies to Ap Obtained by IFA in Transplant Donors and Patients Who Had Previously Been Screened for Lyme Antibody Stratified by C6 Peptide ELISA and Lyme Immunoblot Results
| Cohort . | Cohort Descr iption . | Ap Screen IgG Positive No (%) . | Ap IgG GMT . | Ap Screen IgM Positive No (%) . | Ap IgM GMT . | Analysis Groups . | OR (95% CI) . | P Valuea . |
|---|---|---|---|---|---|---|---|---|
| 1 | Transplant Donors | 3/77 (3.89) | NAb | 0/3 | 0 | 1 vs 7 | 5.9 (1.8–19.4) | .0003 |
| 2 | C6 Negative | 29/182 (15.93) | 83.24 | 1/29 (3.44) | 80 | 2 vs 1 | 4.0 (1.2–13.8) | .017 |
| 3 | Low C6 Positive | 8/28 (28.57) | 128 | 1/8 (12.5) | 20 | 3 vs 1 | 7.3 (1.8–29.6) | .007 |
| 4 | High C6 Positive | 12/39 (30.76) | 203.18 | 4/12 (56.56) | 56.56 | 4 vs 1 | 7.8 (2.1–29.6) | .001 |
| 5 | LIB IgM+/IgG− | 16/46 (34.78) | 378.06 | 13/16 (46.93) | 46.93 | 5 vs 1 | 8.9 (2.4–32.3) | .0003 |
| 6 | LIB IgG+ | 21/74 (28.37) | 301.93 | 11/21 (52.38) | 40 | 6 vs 1 | 7.2 (2.08–25.4) | .0005 |
| 7 | Tick-Exposed (C6 positive and negative) | 86/369 (23.30) | 178.12 | 30/86 (34.88) | 44.89 | NA | NA | NA |
| 8 | C6 Positive | 57/187 (30.48) | 262.30 | 29/57 (50.87) | 44.01 | 8 vs 2c | NA | P < .0001 |
| Cohort . | Cohort Descr iption . | Ap Screen IgG Positive No (%) . | Ap IgG GMT . | Ap Screen IgM Positive No (%) . | Ap IgM GMT . | Analysis Groups . | OR (95% CI) . | P Valuea . |
|---|---|---|---|---|---|---|---|---|
| 1 | Transplant Donors | 3/77 (3.89) | NAb | 0/3 | 0 | 1 vs 7 | 5.9 (1.8–19.4) | .0003 |
| 2 | C6 Negative | 29/182 (15.93) | 83.24 | 1/29 (3.44) | 80 | 2 vs 1 | 4.0 (1.2–13.8) | .017 |
| 3 | Low C6 Positive | 8/28 (28.57) | 128 | 1/8 (12.5) | 20 | 3 vs 1 | 7.3 (1.8–29.6) | .007 |
| 4 | High C6 Positive | 12/39 (30.76) | 203.18 | 4/12 (56.56) | 56.56 | 4 vs 1 | 7.8 (2.1–29.6) | .001 |
| 5 | LIB IgM+/IgG− | 16/46 (34.78) | 378.06 | 13/16 (46.93) | 46.93 | 5 vs 1 | 8.9 (2.4–32.3) | .0003 |
| 6 | LIB IgG+ | 21/74 (28.37) | 301.93 | 11/21 (52.38) | 40 | 6 vs 1 | 7.2 (2.08–25.4) | .0005 |
| 7 | Tick-Exposed (C6 positive and negative) | 86/369 (23.30) | 178.12 | 30/86 (34.88) | 44.89 | NA | NA | NA |
| 8 | C6 Positive | 57/187 (30.48) | 262.30 | 29/57 (50.87) | 44.01 | 8 vs 2c | NA | P < .0001 |
Abbreviations: AP, Anaplasma phagocytophilum; CI, confidence interval; ELISA, enzyme-linked immunosorbent assay; GMT, geometric mean titer; IFA, indirect fluorescent assay; Ig, immunoglobulin; LIB, Lyme immunoblot; NA, not applicable; OR, odds ratio.
*Ap IgM screening was only done for those sera with positive IgG screen results. GMTs were only calculated for those sera with positive screen results. The positivity cutoff for C6 peptide ELISA was 1.1, and the enhanced cutoff for low vs high was 4.
aFisher’s exact test (including OR with 95% CI) for Ap IgG result only. Results were considered statistically significant at P < .05.
bGiven the small number of screen-positive sera in this cohort, GMT was not calculated to avoid bias. Three sera in this cohort had titers of 64 (2) and 128, with negative IgM results suggesting past exposures to Ap.
cComparison of Ap IgG GMTs between cohorts 2 and 8 using Mann-Whitney U test showed statistically significant difference (P < .0001).
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