Anti-CD74 antibodies have no diagnostic value in early axial spondyloarthritis: data from the spondyloarthritis caught early (SPACE) cohort

Table 2 Anti-CD74 antibody and IgA levels in serum from patients in the SPACE cohort

	AxSpA (diagnosis)			Diagnosis and ASAS axSpA criteria			AxSpA (diagnosis) confirmed at 1-year follow up
	Yes (n = 274)	No (n = 286)	P value	Yes (n = 172)	No (n = 238)	P value	Yes (n = 143)	No (n = 64)	P value
Anti-CD74 IgG (OD)	0.50 (0.32–0.65)	0.52 (0.38–0.69)	0.15	0.50 (0.30–0.67)	0.52 (0.39–0.70)	0.075	0.43 (0.30–0.58)	0.48 (0.35–0.61)	0.32
Anti-CD74 IgA (U/mL)	19.9 (11.4–30.6)	14.0 (9.3–26.0)	<0.001	21.8 (11.6–31.9)	13.5 (8.4–22.3)	<0.001	17.6 (9.9–29.0)	13.7 (9.4–23.6)	0.10
Total IgA (g/L)	4.07 (2.90–4.97)	3.37 (2.57–4.66)	<0.001	4.06 (3.01–5.03)	3.29 (2.42–4.62)	0.001	4.02 (2.77–4.78)	3.66 (2.43–4.74)	0.14

Results are shown as median (IQR). Axial spondyloarthritis (axSpA) (diagnosis): SPACE participants diagnosed with axSpA by a rheumatologist at baseline; Assessment of SpondyloArthritis International Society (ASAS) axSpA criteria: SPACE participants fulfilling versus not fulfilling the ASAS axSpA criteria at baseline; Diagnosis and ASAS axSpA: SPACE participants diagnosed as having axSpA and fulfilling the ASAS axSpA criteria versus patients not diagnosed as having axSpA and not fulfilling the ASAS axSpA criteria. Missing values were 5.6% for diagnosis of axSpA, 3% for fulfilling the ASAS axSpA criteria, 30.9% for diagnosis and ASAS axSpA criteria and 58.9% for axSpA diagnosis at 1-year follow up
OD optical density

ISSN: 1478-6362