A new study published in Clinical Immunology investigated the expression of Granzyme B in patients with systemic lupus erythematosus (SLE). Here, isolated peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematosus (SLE)-patients and healthy controls were stimulated with CPG, IgG+IgM and IL-21, in vitro. Patients were sub-grouped as follows: patients with biopsy proven lupus nephritis and those without biopsy proven lupus nephritis; B-cells were analyzed for intracellular Granzyme B expression by flow cytometry. The results showed that the strongest stimulus for Granzyme B secretion of B-cells was IgG+IgM in presence of IL-21. SLE-patients had a significant decreased percentage of Granzyme B+ B-cells, especially SLE-patients with active disease and with lupus nephritis. From the findings, it was inferred that the frequency of GrB+ producing B-cells is reduced in SLE patients. It was speculayted that this may result in an imbalanced B-cell regulation towards effector B-cells which might promote the development of lupus nephritis.