Development and evaluation of a standardized ELISA for the determination of autoantibodies against cN-1A (Mup44, NT5C1A) in sporadic inclusion body myositis

Table 4 Diagnostic performance of anti-cN-1A assays for the diagnosis of sporadic inclusion body myositis

References	Method	Number of sIBM patients	Number of controls	Sensitivity	Specificity (non-sIBM muscle diseases)	Specificity (total controls)
Salajegheh et al. [29]	Western blot against human skeletal muscle extract	25	40	52%	100%	100%
Larman et al. [30]	Dot blot against a synthetic 36-amino acid cN-1A peptide (high cutoff)	47	153	34%^a (70%)^b	98%^a (92%)^b	99%^a
Pluk et al. [31]	Immunoprecipitation with in vitro translated recombinant cN-1A (high cutoff)	94	172	33%^a	96%^a	97%^a
Greenberg et al. [36]	ELISA (IgG) using recombinant cN-1A	50	155	51%^b	ND	94%^b
	ELISA (combined IgG/IgA/IgM) using recombinant cN-1A	50	155	76%^b	ND	91%^b
Goyal et al. [37]	Western blot against recombinant cN-1A expressed in HEK293 cells, ELISA using recombinant cN-1A	25	ND	72%	ND	ND
Herbert et al. [38]	ELISA using three synthetic cN-1A peptides (à 23 amino acids) covering the major immunodominant epitopes	238	524	37%	96%	94%
Lloyd et al. [39]	Western blot against recombinant cN-1A expressed in HEK293 cells	117	383	61%	87%	87%
Kramp et al. (this study)	ELISA (Euroimmun, IgG) using recombinant full-length cN-1A; Laboratory A	31	255	36%	96%	95%
	ELISA (Euroimmun, IgG) using recombinant full-length cN-1A; Laboratory B	51	202	39%	ND	97%

cN-1A cytosolic 5′-nucleotidase 1A, HEK293 human embryonic kidney 293 cell line, ND not determined, sIBM sporadic inclusion body myositis
^aData based on a high cutoff point
^bData obtained by receiver-operating characteristics (ROC) curve analysis using a cutoff for optimal assay accuracy

ISSN: 2038-3274