Usefulness of monitoring of B cell depletion in rituximab-treated rheumatoid arthritis patients in order to predict clinical relapse: a prospective observational study
Résumé
Our objective was to evaluate the contribution of monitoring B cell subset
depletion after rituximab in patients with rheumatoid arthritis (RA) in order
to guide reintroduction to forestall relapse. This prospective, monocentre
study included all RA patients receiving two 1-g rituximab infusions at a
15-day interval. The patients were followed clinically and biologically every 2
months until rituximab reintroduction. The physician was blinded to
lymphocyte-typing results to diagnose relapse and, hence, retreatment.
Among the 39 patients included between March 2010 and December 2011
and followed until April 2013, seven received two rituximab cycles, yielding a
total of 46 cycles for analysis. After the two rituximab cycles, the total
number of CD19+ B cells decreased significantly (0·155 versus 0·0002 G/l,
P < 0·0001), with complete depletions in all patients of CD19+
CD38++CD24++
(transitional) (P < 0·0001) and CD19+
CD27+ (memory) B lymphocytes. A
significant majority of patients relapsed within the 4 months following
repopulation of total B (P = 0·036), B transitional (P = 0·007) and B memory
(P = 0·01) lymphocytes. CD19+ B lymphocyte repopulation preceded clinical
RA relapse and enabled its prediction 4 months in advance. Hence, monitoring of CD19+ B lymphocytes could serve as a tool to predict those relapses