Atypical C-ANCA following high dose intravenous immunoglobulin

Neutropenia following intravenous immunoglobulin therapy in adult patients with immune thrombocytopenic purpura: A single center experience and literature review

The purpose of this study was to evaluate neutropenia following intravenous immunoglobulin (IVIG) therapy in adults with immune thrombocytopenic purpura (ITP).Our analysis included 88 patients with ITP, who received IVIG from January 2006 to March 2016, at Pusan National University Hospital in Korea. Their white blood cell (WBC) count and absolute neutrophil count (ANC) before and after IVIG treatment were analyzed.Of 88 patients, 24 patients (27.3%) were male, and 64 patients (72.7%) were female. Neutropenia developed in 8 patients (18.7%) after IVIG treatment. In patients with a decrease in WBC count and ANC compared to baseline, median WBC count decreased from 6280/μL to 4530/μL after IVIG therapy, and median ANC decreased from 3840/μL to 2840/μL after IVIG therapy. The neutropenia induced by IVIG had resolved spontaneously after several days, and the mean recovery time was 8.72 days after the completion of the IVIG treatment. During the neutropenic episodes, only one patient developed neutropenic fever, which subsided soon without any treatment.The results of this study suggest that IVIG may cause neutropenia commonly in adults with ITP, and it seems to be transient and self-limited. This study is meaningful as the first report that not only pediatric ITP patients may develop neutropenia post IVIG administration, but also adult patients suffering ITP.

Effects of IVIg treatment on autoantibody testing in neurological patients: marked reduction in sensitivity but reliable specificity

BACKGROUND

Therapy of autoimmune diseases of the central and peripheral nervous system with intravenous IgG immunoglobulin (IVIg) is well established. Since IVIg is produced from pooled human plasma, autoantibodies can be found in IVIg products and, accordingly, in patient sera after transfusion. The de novo evidence or disappearance of anti-neural autoantibodies after IVIg treatment has so far not been systematically examined.

METHODS

We screened 50 neurological patients before and after IVIg treatment for classical onconeural and the most common neurological surface autoantibodies as well as for ganglioside autoantibodies and 23 different antinuclear autoantibodies using immunoblot or cell-based indirect immunofluorescence assays. Furthermore, we screened 31 neurological patients with previously known seropositivity for disappearance of the corresponding antibody after treatment.

RESULTS

After IVIg treatment, 90% of all sera were de novo positive for antinuclear antibodies, especially for Ro-52. In contrast, 94% of all sera did not show any de novo-positive anti-neural antibodies. In the remaining three cases, titers were very low. Importantly, 12.9% of all tested sera of patients with known antibody positivity turned false negative after IVIg treatment and titers were falsely low in 37% of the remaining sera.

CONCLUSIONS

Here, we present for the first time results of a broad screening for clinically relevant autoantibodies before and after IVIg treatment in neurological patients. We identified a high specificity but reduced sensitivity for anti-neural antibody testing after IVIg transfusion. In contrast, antinuclear antibody testing is not reliable after IVIg treatment. These results are of high practical importance for diagnostic of neuroimmunological diseases.

Effect of intravenous immunoglobulin administration on erythrocyte and leucocyte parameters

BACKGROUND

Intravenous immunoglobulins (IVIG) are an attractive therapeutic tool for therapy of toxic epidermal necrolysis and severe forms of certain autoimmune diseases, including dermatomyositis, autoimmune blistering diseases, systemic vasculitis and lupus erythematodes.

OBJECTIVES

Prompted by a case of IVIG-associated haemolytic anaemia, the effects of IVIG administrations on haematological parameters in patients with dermatological conditions were investigated.

METHODS

Erythrocyte and leucocyte parameters were retrospectively analysed in 16 patients who had received IVIG at doses from 1 to 3 g/kg bodyweight (n = 35 cycles). The influence of IVIG on leucocyte survival was determined in vitro.

RESULTS

Decreased absolute erythrocyte numbers, haemoglobin and haematocrit levels and a case of haemolytic anaemia were linked to transfusion of high-, but not low-dose IVIG. In contrast, leucopenia post-IVIG occurred in the vast majority of the recipients, unrelated to the administered IVIG amounts. In vitro investigations revealed a dose-dependent impairment of cell survival by IVIG in the neutrophil and monocyte, but not in the lymphocyte subpopulations. In several IVIG preparations, substantial amounts of blood group anti-A/anti-B antibodies were detected which could have accounted for the observed changes in the haematological parameters in our study cohort.

CONCLUSIONS

IVIG products should be administered strictly according to indications. Commercially available IVIG products can contain blood group-specific antibodies that may induce haemolysis in some recipients. Monitoring of blood counts during applied IVIG therapy, especially when high doses are administered, is recommended.

Does a gating policy for ANCA overlook patients with ANCA associated vasculitis? An audit of 263 patients

BACKGROUND

Antineutrophil cytoplasm antibodies (ANCA) are used as diagnostic markers for small-vessel vasculitis of the Wegener Granulomatosis-microscopic polyangiitis (WG-MPA) spectrum, but if testing is applied indiscriminately, its value is diminished. The authors measured the effect of a targeted ANCA testing policy introduced in our institution in an attempt to improve the diagnostic value of testing in patients with suspected vasculitis.

METHODS

The authors measured the rate of ANCA requests at a single regional centre in the year prior to and following the introduction of clinical guidelines to ensure appropriate test usage. The authors also audited clinical outcomes in patients in whom ANCA testing was declined.

RESULT

Following implementation of the antineutrophil cytoplasm antibodies (ANCA) gating policy, the number of monthly ANCA tests carried out fell from 287+/-30 to 143+/-18 (p<0.0001) and was associated with an increased rate of positivity, from 18.5% (95% CI 17.0 to 20.1%) to 30.3% (27.5 to 33.1%; p<0.0001). The authors undertook a careful review of the case records from 263 patients in whom testing was declined according to the gating policy over an 8-month period. After 6 months' follow-up, no diagnoses of small-vessel vasculitis of the WG-MPA spectrum were reached.

CONCLUSIONS

The rational use of ANCA testing to aid in the diagnosis of vasculitis should include a clinical gating policy to improve diagnostic performance. Adherence to a gating policy for ANCA testing coupled with close liaison between clinician and laboratory does not result in either a missed or delayed diagnosis of small-vessel vasculitis belonging to the WG-MPA spectrum.

Antineutrophil cytoplasmic antibody (ANCA) testing of routine sera varies in different laboratories but concordance is greater for cytoplasmic fluorescence (C-ANCA) and myeloperoxidase specificity (MPO-ANCA)

Most laboratories screen for antineutrophil cytoplasmic antibodies (ANCA) with indirect immunofluorescence (IIF) and confirm cytoplasmic (C-ANCA) and perinuclear (P-ANCA) staining with ELISAs for proteinase 3 (PR3) and myeloperoxidase (MPO) specificities. This study determined the concordance of ANCA test results from 48 diagnostic laboratories participating in a national Quality Assurance programme, that used different assays and methods and varied in expertise. Laboratories were circulated with a questionnaire about their techniques, and provided with 24 sera for testing over a 30 month period. Results for individual sera were compared with the 'observed consensus' found in more than 50% of laboratories. The 23 laboratories (48%) that responded to the questionnaire used 5 different IIF substrates and 11 ELISAs, and differed in other aspects of testing. Concordance for ANCA test results was greater for IIF-positive (n=22, median 96%, range 68%-100%) than an IIF-negative serum (median 64%); for C-ANCA (n=8, median 89%, range 66-100%) rather than P-ANCA (n=10, median 76%, range 52-88%); for MPO-ANCA (n=5, median 100%) rather than PR3-ANCA (n=7, median 89%, range 82-100%); and for strongly-positive (n=2, median 97%, range 96-97%) rather than low positive PR3-ANCA (n=4, median 80%, range 74-86%). Concordance for test results might be improved with further standardisation of testing methodologies.

Intravenous immunoglobulins contain naturally occurring antibodies that mimic antineutrophil cytoplasmic antibodies and activate neutrophils in a TNFα-dependent and Fc-receptor–independent way

Intravenous immunoglobulin (IVIg) preparations are increasingly used for therapy of several neuroimmunologic diseases. IVIg therapy is considered safe, although serious side effects like aseptic meningitis, cerebral vasospasm, or ischemic encephalopathy have been reported. These side effects are frequently associated with neutrophilic pleocytosis in the cerebrospinal fluid (CSF), suggesting a neutrophil-mediated mechanism. To elucidate the potential role of neutrophil activation, we analyzed IVIg preparations from 5 different commercial sources for the presence of antineutrophil cytoplasmic antibody (ANCA)–like immunoglobulins against ethanol-fixed peripheral-blood neutrophils, purified human antigens, and a panel of human and nonhuman tissues. All IVIg batches tested (n = 13) contained atypical ANCAs (IgG titer up to 1:2048, IgA up to 1:512). Moreover, all preparations were capable of inducing hydrogen peroxide production in TNFα-primed human neutrophils, with a significant correlation (P < .005) between atypical ANCA titers in IVIg preparations and neutrophil activation. Fc-mediated binding and activation was ruled out by the use of IVIg-F(ab′)2 fragments. Our findings strongly suggest that in vivo activation of TNFα-primed neutrophils by atypical ANCAs of IVIg may contribute to the side effects of IVIg therapy and for the first time demonstrate that the activation of neutrophil granulocytes by IVIg occurs in an Fc receptor (FcR)–independent, hence antigen-dependent, way.

Is Wegener's granulomatosis an autoimmune disease?

Wegener's granulomatosis is a multisystem disease characterized by granulomata of the respiratory tract and systemic necrotising vasculitis. There is a strong and specific association with autoantibodies directed against proteinase 3, a constituent of neutrophril azurophilic granules. Antibody titers correlate with clinical disease activity and predict relapses. The disease responds favorably to immunosuppressive therapy. The pathogenicity of antineutrophil cytoplasmic antibodies (ANCA), however, remains unproven. In vitro, the expression of proteinase-3 and other ANCA antigens on the surface of neutrophils and monocytes can be induced by priming with proinflammatory cytokines. Antineutrophil cytoplasmic antibodies are then able to activate these leukocytes, stimulating degranulation, the production of reactive oxygen species, and the secretion of further cytokines. Neutrophils activated by ANCA, and possibly ANCA alone, directly damage endothelial cells in vitro. An animal model of proteinase 3-ANCA-induced vasculitis has not been found. Antineutrophil cytoplasmic antibodies directed against another antigen, myeloperoxidase, are not sufficient to cause vasculitis but they promote damage in certain animal models. Thus, a considerable amount of evidence supports the notion that Wegener's granulomatosis is an autoimmune disease.