Antinuclear antibody prevalence in a general pediatric cohort from Mexico City: discordance between immunofluorescence and multiplex assays

Figures & data

Figure 1 Representative photomicrographs of antinuclear antibody (ANA) patterns at 400× magnification. (A) negative ANA; (B) positive/homogeneous pattern; (C) positive/speckled pattern; (D) positive/nucleolar pattern.

Figure 2 (A) ANA titers and patterns, by indirect IFA. (B) Autoantibody specificities by multiplex-11 assay. Four specificities did not yield any positives (ribosomal P, SS-A, centromere B, and Jo-1).

Abbreviations: ANA, antinuclear antibody; dsDNA, double-stranded DNA; IFA, immunofluorescence assay.

Table 1 ANA positivity according to assay method in a pediatric cohort (aged 9–17 years) from Mexico City

	Overall, n=114, No (%)	Female, n=54, No (%)	Male, n=60, No (%)	P-value (female vs male)
ANA positivity, by assay method
IFA (≥1:80)	18 (15.8)	11 (20.4)	7 (11.7)	NS
Multiplex-11	11 (9.6)	7 (13.0)	4 (6.7)	NS
Multiplex-10 (excludes dsDNA+)	8 (7)	5 (9.3)	3 (5.0)	NS
Titers among IFA+				NS
1:80	6 (33.3)	5 (45.5)	1 (14.3)	–
1:160	4 (22.2)	1 (9.1)	3 (42.9)	–
1:320	4 (22.2)	2 (18.2)	2 (28.6)	–
1:1280	2 (11.1)	2 (18.2)	0 (0)	–
1:2560	2 (11.1)	1 (9.1)	1 (14.3)	–
Fluorescence patternsa				NS
Homogeneous	8 (44.4)	4 (36.4)	4 (57.1)
Nucleolar	1 (5.6)	0 (0)	1 (14.3)
Speckled	9 (50)	7 (63.6)	2 (28.6)
Number of Ag+ specificitiesb				NS
1	8 (7)	5 (9.3)	3 (5)	–
2	2 (1.8)	2 (3.7)	0 (0)	–
5	1 (0.9)	0 (0)	1 (1.7)	–

Notes:

a Among IFA positives,

b among multiplex-11 positives.

Abbreviations: Ag, antigen; ANA, antinuclear antibody; dsDNA, double-stranded DNA; IFA, immunofluorescence assay; NS, not significant.

Figure 3 Age distributions according to ANA screening status by indirect IFA and multiplex-11 assays.

Abbreviations: ANA, antinuclear antibody; IFA, immunofluorescence assay.

Figure 4 Proportional Venn diagram displaying overlap in positivity for ANA assay methods (n=114). Corresponding sensitivity, specificity, and kappa estimates are presented, for multiplex compared to IFA (≥1:80) as the “gold standard”. Multiplex-10 excludes the dsDNA antigen from the full multiplex-11 panel.

Abbreviations: ANA, antinuclear antibody; dsDNA, double-stranded DNA; IFA, immunofluorescence assay.

Table 2 Comparison of IFA titers and number of multiplex-positive antigens

	Multiplex			Total
	Negative	dsDNA+ only	Other Ag+
IFA titer
<1:80	89	3	4	96
(neg)
1:80	4	0	2	6
1:160	4	0	0	4
1:320	3	0	1	4
1:1280	2	0	0	2
1:2560	1	0	1	2
Total	103	3	8	114

Abbreviations: Ag, antigen; IFA, immunofluorescence assay; dsDNA, double-stranded DNA; neg, negative.