Notably, the reduction of the serological gap by 9 % following testing for IgG reactivity to UH-RA.1 and UH-RA.21 (combined as UH-RA.PANEL2), as reported recently (Fig. 4a) [12], was markedly improved to a reduction by 13 % after including anti-UH-RA.1 IgM testing in the panel (Fig. 4b). Here, CD40LG is linked to rheumatoid arthritis.