IVIg increases interleukin-11 levels, which in turn contribute to increased platelets, VWF and FVIII in mice and humans

Abstract

The mechanisms of action of intravenous immunoglobulins (IVIg) in autoimmune diseases are not fully understood. The fixed duration of efficacy and noncumulative effects of IVIg in immune thrombocytopenia (ITP) and acquired von Willebrand disease (AVWD) suggest other mechanisms besides immunological ones. Additionally to the peripheral destruction of platelets in ITP, their medullary hypoproduction emerged as a new paradigm with rescue of thrombopoietin receptor agonists (TPO-RA). In an ITP mouse model, interleukin (IL)-11 blood levels increase following IVIg. IL-11 stimulates the production of platelets and other haemostasis factors; recombinant IL-11 (rIL-11) is thus used as a growth factor in post-chemotherapy thrombocytopenia. We therefore hypothesized that IVIg induces IL-11 over-production, which increases platelets, VWF and factor VIII (FVIII) levels in humans and mice. First, in an ITP mouse model, we show that IVIg or rIL-11 induces a rapid increase (72 h) in platelets, FVIII and VWF levels, whereas anti-IL-11 antibody greatly decreased this effect. Secondly, we quantify for the first time in patients with ITP, AVWD, inflammatory myopathies or Guillain-Barré syndrome the dramatic IL-11 increase following IVIg, regardless of the disease. As observed in mice, platelets, VWF and FVIII levels increased following IVIg. The late evolution (4 weeks) of post-IVIg IL-11 levels overlapped with those of VWF and platelets. These data may explain thrombotic events following IVIg and open perspectives to monitor post-IVIg IL-11/thrombopoietin ratios, and to assess rIL-11 use with or without TPO-RA as megakaryopoiesis co-stimulating factors to overcome the relative hypoproduction of platelets or VWF in corresponding autoimmune diseases, besides immunosuppressant.

Keywords: Factor VIII; acquired von Willebrand disease; immune thrombocytopenia; interleukin-11; intravenous immunoglobulin.

Fig. 1

Evolution of platelet, Factor VIII (FVIII) and von Willebrand factor (VWF) levels in a mouse model of immune thrombocytopenic purpura (ITP). A dose escalation mouse model of passive ITP was induced in C57BL/6 mice by daily injection of a platelet‐depleting antibody, MWReg30, until the end of the experiment. The mice were divided into four groups of five mice each that received one of the four following additional interventions at day 2, 6 h before blood sample collection: (1) intravenous immunoglobulin (IVIg) (2 g/kg), (2) IVIg plus mouse anti‐interleukin (IL)‐11 antibody (100 µg/mouse), (3) recombinant mouse IL‐11 (rIL‐11) (10 µg/mouse) or (4) phosphate‐buffered saline (PBS) (equivalent volume of IVIg). (a) Platelet count (G/L) [mean ± standard error of the mean (s.e.m.), n = 5 mice/group) on day 0 (before) and day 2 (after) MWReg30 injection, uniformly and dramatically decreased at day 2. (b) Platelet levels (mean ± s.e.m., n = 5 mice/group) measured on day 4 in various treatment groups. Whereas platelet levels remained low at day 4 compared to day 2 in PBS and IVIg plus mouse anti‐IL‐11 monoclonal antibody groups, their levels significantly and comparably increased in both IVIg and mouse rIL‐11 groups. (c) FVIII levels in the plasma was measured by enzyme‐linked immunosorbent assay (ELISA) (mean ± s.e.m., n = 5 mice/group) on days 0, 2 and 4. The levels of FVIII significantly increased in the corresponding groups compared to levels measured in PBS, IVIg and IVIg plus mouse anti‐IL‐11 antibody groups, remaining significant on day 4. However, there was no significant difference in FVIII levels in IVIg versus IVIg plus mouse anti‐IL‐11 antibody groups at days 0, 2 and 4, these levels being already initially normal and remaining above the lower limit. (d) VWF levels in the plasma were measured by ELISA (mean ± s.e.m., n = 5 mice/group) on days 0, 2 and 4. The levels of VWF showed a slight decrease from days 0 to 2 in all four groups. At day 4, the levels of VWF were significantly and similarly increased only in rIL‐11 and IVIg groups. Of note, neutralization of IL‐11 completely abrogated the effect of IVIg on VWF. ^* P < 0·05; ^** P < 0·01; ^*** P < 0·001; n.s. = not significant by two‐way analysis of variance (anova).

Fig. 2

Induction of interleukin (IL)‐11 and enhancement of haemostatic factors levels following intravenous immunoglobulin (IVIg) is a universal phenomenon. IL‐11 was measured via enzyme‐linked immunosorbent assay (ELISA) in the plasma of inflammatory myopathies (IM, n = 12) and acquired von Willebrand disease (AVWD, n = 4) patients and healthy controls (controls, n = 6), or in the serum of immune thrombocytopenia (ITP, n = 6) patients. The median IL‐11 levels increased in all patients from the steady state to 72 h following IVIg, regardless of the underlying disease. The lower increase in ITP patients was observed in serum. ^* P < 0·05; by Student’s t‐test.

Fig. 3

Increase in the levels of von Willebrand factor (VWF) before and 72 h after intravenous immunoglobulin (IVIg) in inflammatory myopathies (IM, n = 12), immune thrombocytopenic purpura (ITP, n = 6), and acquired von Willebrand disease (AVWD, n = 4) patients and healthy controls (controls, n = 6). VWF and factor VIII (FVIII) levels were measured in the plasma of AVWD patients while VWF was measured in the serum of ITP patients by enzyme‐linked immunosorbent assay (ELISA) before and 72 h following IVIg. Therefore, FVIII could not be measured in serum samples. In addition, VWF was measured in the plasma of six healthy donors. IVIg significantly increased the median levels of VWF (a) and FVIII (b), regardless of the underlying disease. ^* P < 0·05; ^*** P < 0·001; by Student’s t‐test.

Fig. 4

Increase in the levels of von Willebrand factor (VWF), platelets and IL‐11 in patients with acquired VWF or immune thrombocytopenia following intravenous immunoglobulin (IVIg). IL‐11, VWF and platelet levels were measured in acquired VWF (AVWD, n = 4) and immune thrombocytopenia (ITP, n = 6) before and 72 h post‐IVIg therapy. (a) IVIg significantly increased the levels of IL‐11 in both AVWD and ITP patients and also the levels of platelets in ITP patients, whereas platelet levels did not exhibit significant changes in AVWD patients. (b) Similarly, both IL‐11 and VWF levels significantly increased following IVIg in both patient groups. ^* P < 0·05; ^** P < 0·01; ^*** P < 0·001; by Student’s t‐test.

Fig. 5

Parallel kinetics of interleukin (IL)‐11 and von Willebrand factor (VWF) levels following intravenous immunoglobulin (IVIg): assessment before and beyond the half‐life of infused IgG in serum of Guillain–Barré syndrome (GBS) patients. IL‐11 was quantified in the serum of five GBS patients before at 1 and 4 weeks following IVIg. (a) IL‐11 from GBS patients was undetectable in serum before IVIg, then its levels significantly increased at week 1 and significantly decreased at week 4, remaining at a detectable level. (b) VWF levels exhibited an evolution parallel to those of IL‐11. Initial normal levels of VWF at baseline increased following IVIg, then decreased to baseline values 4 weeks later. ^* P < 0·05; n.s. = not significant; by Student’s t‐test.