Session Information
Date: Monday, November 9, 2015
Title: Pediatric Rheumatology - Clinical and Therapeutic Aspects II: Pediatric Systemic Lupus Erythematosus
Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Background/Purpose: Elevated levels of cell-bound complement
activation products (C4d deposition on erythrocytes [EC4d] and B lymphocytes
[BC4d], CBCAPS) have been demonstrated to be sensitive and specific biomarkers in
the differential diagnosis of adult systemic lupus erythematosus
(SLE) and other rheumatic diseases. We sought to evaluate the usefulness of CBCAPS
in the setting of childhood-onset SLE (cSLE).
Methods: This validation cohort included 28
patients with cSLE all diagnosed prior to their 19th
birthdays, and 21 patients with juvenile idiopathic arthritis (JIA). All
subjects fulfilled American College of Rheumatology SLE classification criteria.
Venous blood was collected and shipped overnight to the reference clinical
laboratory conducting the diagnostic testing for CBCAPS and autoimmune markers
including antinuclear antibodies (ANA), anti-dsDNA
antibodies and other cellular autoantibodies. The CBCAPS multi-analyte assay combining these markers in two consecutive
tiers of analysis as currently approved by the Department of Health in the
State of NY was calculated. Diagnostic test results were reported as positive
(suggestive of SLE) or negative (suggestive of non-SLE). Test performances in
this validation cohort were assessed using sensitivity, specificity, and
positive and negative likelihood ratios (LR). All laboratory personnel were
blinded to subject diagnosis during the pre-analytical, analytical and
post-analytical phase of testing.
Results: The results of the cSLE
and JIA patients are shown in the Table. Elevated CB-CAPS resulted in 28%
higher sensitivity for cSLE than low complement, and
higher specificity. After employing the two-tier analysis previously described,
the CBCAPS multi-analyte assay yielded 81% sensitivity
(22/27, one indeterminate test assessment) and a specificity of 84% (16/19, one
indeterminate and one equivocal test assessment). Positive LR was 5.4 and
negative LR was 0.2. Of note, the 5 cSLE
patients presenting with a negative CBCAPS multi-analyte
assay assessment were clinically in remission.
Conclusion: These pilot findings suggest that
CBCAPS could provide useful markers for cSLE and
differentiation from other autoimmune diseases.
Table: Patient demographics and results
of CBCAPS assays
|
SLE (n=28)
|
JIA (n=21)
|
|
|
Age
|
18±2 |
17±3 |
|
Female %
|
75% |
77% |
|
Duration of disease Mean SLE disease activity index
|
4.7±3.2 4.3±3.8 (range 0-16) |
4.4±3.4 |
|
Low Complement
|
50% (14/28) |
19% (4/21) |
|
ANA (indirect immunofluorescence)
|
93% (26/28) |
52% (11/21) |
|
Anti-dsDNA (confirmed Crithidia)
|
54% (15/28) |
5% (1/21) |
|
Anti-Smith
|
18% (5/28) |
0% (0/21) |
|
EC4d>14 net mean fluorescence index (MFI) EC4d>75 net MFI
|
64% (18/28) 19% (4/21) |
14% (3/21) 0% (0/21) |
|
BC4d>60 net MFI BC4d>200 net MFI
|
63% (17/27) 14% (3/27) |
4% (1/21) 0% (0/21) |
|
Elevated CBCAPS (EC4d>14 units MFI, or BC4d>60 units MFI)
|
78% (21/27) |
14% (3/21) |
To cite this abstract in AMA style:
Askanase A, Hui-Yuen J, Conklin J, Barken D, O'Malley T, Li XQ, Bermudez LM, Eichenfield A, Starr AJ, Imundo LF, Dervieux T. Cell-Bound Complement Activation Products Have High Sensitivity and Specificity in Childhood-Onset Systemic Lupus Erythematosus and Juvenile Idiopathic Arthritis [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/cell-bound-complement-activation-products-have-high-sensitivity-and-specificity-in-childhood-onset-systemic-lupus-erythematosus-and-juvenile-idiopathic-arthritis/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/cell-bound-complement-activation-products-have-high-sensitivity-and-specificity-in-childhood-onset-systemic-lupus-erythematosus-and-juvenile-idiopathic-arthritis/