Features of rituximab-induced killing of B lymphocytes

Frequency of Th17 CD20+ cells in the peripheral blood of rheumatoid arthritis patients is higher compared to healthy subjects

Introduction

Rheumatoid arthritis (RA) is considered a T cell driven autoimmune disease, therefore, the ability of B cell depleting biologics, e.g., anti-CD20 antibodies, to alleviate RA is unclear. This study examined the proportions of IL-17-secreting lymphocytes in the blood of healthy subjects and RA patients and determined if Th17 cells belong to a CD20+ subset of T cells.

Methods

Fluorescence-activated cell sorting and confocal microscopy verified CD3, CD4/CD8 and CD20-staining of T cells. IL-17 secretion was determined using a commercial assay.

Results

In healthy subjects and RA patients blood, the median percentage of total CD20+ lymphocytes was similar (7.5%; n = 6 and 10.3%; n = 9, respectively) and comprised predominantly of B cells (~ 86%). However, 2-4% of CD3+ T cells from both healthy subjects (n = 7) and RA (n = 8) individuals co-expressed CD20. The peripheral blood of healthy subjects contained few IL-17-secreting CD20+ T cells (< 0.1%; n = 6). In contrast, in RA blood a median and interquartile range % of, 24.2%; IQR 28.5 of IL-17-secreting T cells were CD20+ (n = 9; p = 0.02).

Conclusions

In the blood of RA patients, a greater proportion of Th17 cells are of a CD20+ phenotype compared to healthy individuals. These cells may represent an additional target for anti-CD20 therapies.

Anti-CD20 treatment in primary Sjögren's syndrome

We performed a search for publications on rituximab (Rtx) in the treatment of primary Sjögren's syndrome (pSS), and assessed the reports for the efficacy of the drug on complaints like sicca symptoms, systemic manifestations and pSS associated lymphoma. We also reviewed the effects on laboratory parameters and potential adverse effects. From the published literature there is little evidence supporting Rtx to have an effect on sicca symptoms, and there is particularly lack of objective improvements in measures of oral and ocular dryness. Systemic manifestations such as fatigue, synovitis, arthralgia, cryoglobulinaemia-related vasculitis, neurological, renal and pulmonary involvement all seem to react favourably to Rtx treatment. The effect on pSS associated non-Hodgkin's lymphoma is also beneficial. Rheumatoid factor concentration is decreasing during Rtx treatment. The levels of anti-SSA and -SSB antibodies are, however, unaltered according to the majority of the studies. The most common complications to Rtx treatment are mild and transient infusion related reactions. Delayed moderate-to-severe reactions are less common, and occur mostly in patients who develop human anti-chimeric antibodies. In conclusion, Rtx is a promising treatment option for severe pSS with systemic complications, but more data from randomized controlled trials are warranted before conclusions on the drug's role can be made with more accuracy.