Serum thrombopoietin levels and anti-thrombopoietin antibodies in systemic lupus erythematosus

Primary Immune Thrombocytopenic Purpura (ITP) and ITP Associated with Systemic Lupus Erythematosus: A Review of Clinical Characteristics and Treatment Modalities

Immune thrombocytopenic purpura (ITP) is an immune-mediated disorder characterized by the destruction of platelets and megakaryocytes due to autoantibodies against the platelet surface proteins. ITP without any apparent cause of thrombocytopenia is defined as primary ITP, and ITP in the setting of SLE is secondary ITP, which can be diagnosed after excluding other causes of thrombocytopenia by history, physical examination, and laboratory testing. Patients with ITP associated with SLE have higher median platelet count and less bleeding manifestations compared to the patients with primary ITP. It can be very challenging to diagnose primary ITP in SLE patients as other causes of thrombocytopenia including drug-induced thrombocytopenia, antiphospholipid syndrome, and thrombotic microangiopathic process should be ruled out. Corticosteroids are the main modality of treatment. IVIG can be used in severe cases. Splenectomy was found to be less effective in ITP associated with SLE compared to primary ITP. Control of disease activity with immunosuppressive therapy can be helpful in some cases associated with active disease flares in SLE patients.

Investigating the Role of Anti-TPO Antibodies in HIV-Associated Thrombocytopenia before and after Initiation of HAART: A Case-Control Longitudinal Study

This longitudinal, case-control study aimed to investigate the role of thrombopoietin (TPO) and anti-TPO antibodies in HIV-associated thrombocytopenia, focusing on the changes seen before and after the initiation of highly active antiretroviral therapy (HAART). Patients were assessed before and at least six months after the initiation of HAART. In total, 75 PLWHIV (age/sex-matched and randomized at 2:1, according to thrombocytopenia status) were included in this study. The baseline assessment revealed significantly higher TPO levels in thrombocytopenic patients (140.45 vs. 106.8 mg/mL, p = 0.008). Furthermore, anti-TPO-positive patients displayed lower platelet counts (109,000 vs. 139,000/L, p = 0.002) and TPO levels (114.7 vs. 142.7 mg/mL, p = 0.047). Longitudinally, HAART initiation reduced the frequency of thrombocytopenia from 75.47% to 33.96% (p < 0.001) and elevated the median platelet counts from 131,000 to 199,000 (p < 0.001). No significant difference in median platelet counts was found post-HAART among the anti-TPO subgroups (p = 0.338), a result contrasting with pre-HAART findings (p = 0.043). Changes in anti-TPO status corresponded with significant platelet count alterations (p = 0.036). Notably, patients who became anti-TPO negative showed a median increase of 95,000 platelets (IQR: 43,750-199,500). These marked differences between subgroups underscore the potential role of anti-TPO antibodies in modulating the hematological response to HAART. Further research is needed to elucidate the complex interplay between HIV infection, HAART, and thrombocytopenia.

Management of Severe Refractory Systemic Lupus Erythematosus: Real-World Experience and Literature Review

Systemic lupus erythematosus (SLE) is a highly heterogeneous disease affecting multiple organs and is characterized by an aberrant immune response. Although the mortality of SLE has decreased significantly since the application of glucocorticoids, severe or refractory SLE can potentially cause irreversible organ damage and contribute to the disease morbidity and mortality. Early recognition of severe SLE or life-threatening conditions is of great challenge to clinicians since the onset symptoms can be rapid and aggressive, involving the visceral organs of the neuropsychiatric, gastrointestinal, hematologic, renal, pulmonary, and cardiovascular systems, etc. Additionally, SLE patients with specific comorbidities and detrimental complications could lead to a clinical dilemma and contribute to poor prognosis. Prompt and adequate treatment for severe refractory SLE is crucial for a better prognosis. However, as evidence from well-designed randomized controlled trials is limited, this review aims to provide real-world evidence based on cohort studies from Peking Union Medical College Hospital, the national tertiary referral center in China, together with the literature, on clinical characteristics, risks and prognostic factors, and treatment strategies for severe and/or refractory SLE.

[Secondary ITP in adults]

Secondary forms of immune thrombocytopenia (ITP) represent approximately 20% of all ITP cases in adulthood and this rate increases with age. Since some causes may influence both the prognosis and outcome but also the management of ITP, a minimal workup must be performed at ITP diagnosis to look for an associated or underlying cause. Among adults, B-cell lymphomas and mainly chronic lymphocytic leukemia, systemic auto-immune diseases such as systemic lupus or primary immunodeficiencies mainly represented by common variable immunodeficiency are the most frequent causes of secondary ITP. Whereas first-line therapy used for secondary ITP is usually similar to the one commonly used in primary ITP and relies mostly on corticosteroids±intravenous immunoglobulin according to the severity of bleeding, second and third-line treatments must take into account the type and degree of activity of the underlying disease.

A Pilot Study on the Effect of Anti-Thrombopoietin Antibody on Platelet Count in Patients with Type 2 Diabetes

Thrombopoietin (THPO) is a circulatory cytokine that plays an important role in platelet production. The presence of anti-THPO antibody relates to thrombocytopenia and is rarely seen in hematopoietic and autoimmune diseases. To date, there had been no reports that focused on the anti-THPO antibody in patients with type 2 diabetes mellitus (T2DM). To evaluate prevalence of the anti-THPO antibody in patients with T2DM and the relationship between anti-THPO antibody and platelet count, a cross-sectional study was performed on 82 patients with T2DM. The anti-THPO antibody was measured by ELISA using preserved sera and detected in 13 patients. The average platelet count was significantly lower in patients with the anti-THPO antibody than in those without the anti-THPO antibody. Multivariate linear regression analyses showed a significant relationship between the anti-THPO antibody and platelet count, after adjusting for other variables. To our best knowledge, this was the first report on the effect of the anti-THPO antibody on platelet count in patients with T2DM. Further investigation is needed to validate the prevalence and pathological significance of the anti-THPO antibody in patients with T2DM.

Sjogren's syndrome complicating pancytopenia, cerebral hemorrhage, and damage in nervous system: A case report and literature review

RATIONALE

Sjogren's syndrome(SS) is a chronic autoimmune disease, which damages exocrine glands especially salivary and lacrimal glands, with xerostomia and xerophthalmia as common symptoms.

PATIENT CONCERNS

We report a case of a 49-year-old woman presented with pancytopenia. Her laboratory examinations lead us diagnose her as Sjogren's syndrome complicating pancytopenia. She had neurological symptoms during her treatment, which represent only 4.5% of Sjogren's syndrome complicating damage in nervous system.

DIAGNOSES

Sjogren's syndrome complicating pancytopenia.

INTERVENTIONS

Dexamethasone (40mg QD for 4 days) and immunoglobulin (25g QD for 2 days) were administered for intensive treatment followed by oral methylprednisolone 40mg QD as maintenance treatment. Total glucosides of paeony 0.6g TID and danazol 0.2g BID per os were given. We also gave her Piperacillin-tazobactam and moxifloxacin for anti-infection and Fluconazole for anti-fungal therapy, as well as other supportive treatments.

OUTCOMES

Follow-up of the patient observed the normalization of peripheral blood cell count, immunity indices and neurological examinations 6 months after discharge.

LESSONS

For patients presented with blood system abnormalities unilineage or multiple-lineage cytopenia in particular, history investigations and relevant examinations should be considered to exclude the existence of autoimmune diseases like Sjogren's syndrome.

Lupus thrombocytopenia: pathogenesis and therapeutic implications

Systemic Lupus Erythematosus (SLE) is frequently complicated by cytopenias. Thrombocytopenia is usually non severe and its frequency ranges from 20% to 40%. It is mostly an autoimmune process caused by autoantibodies against platelet surface glycoproteins and it is associated with worse prognosis in SLE. It can also be a result of SLE treatment with azathioprine, methotrexate and rarely hydroxychloroquine or thrombotic microangiopathy or macrophage activation syndrome. If thrombocytopenia is mild (>50×10⁹/L) and there is no other evidence of disease there is no need of therapy. Severe thrombocytopenia is less frequent and needs therapeutic management. Corticosteroids are the cornerstone of therapy. Continuous high dose oral prednisolone or pulse high dose methylprednisolone (MP) with or without intravenous immune globulin are used in the acute phase. Second line agents (hydroxychloroquine, danazol, azathioprine, cyclosporine, mycophenolate mofetil, cyclophosphamide, rituximab) are usually needed. Splenectomy is indicated for recurrent or resistant cases. There are no evidence-based guidelines to facilitate selection of one drug over another but certainly the co-existence of other systemic SLE manifestations must be taken into account. Newer therapies are emerging although there is no consensus on the treatment of refractory lupus thrombocytopenia due to the absence of controlled randomized trials.

Bone Marrow Megakaryocytes May Predict Therapeutic Response of Severe Thrombocytopenia in Patients with Systemic Lupus Erythematosus

Objective.

To analyze the predictive value of megakaryocyte counts in bone marrow (BM-MK) for determining the therapeutic response of severe thrombocytopenia (TP) in patients with systemic lupus erythematosus (SLE).

Methods.

Thirty-five patients with SLE with severe TP (platelet count ≤ 50 × 109/l) from the Peking Union Medical College Hospital admitted between 2007 and 2014 with appreciable bone marrow aspiration results were analyzed retrospectively. The associations between therapeutic response and clinical manifestations, laboratory findings including BM-MK counts, were evaluated.

Results.

Seventeen (49%) and 8 (23%) patients achieved a complete response (CR) and a partial response (PR), respectively, and 10 had no response (NR). The BM-MK counts in each group were 102 ± 25 (0–322), 136 ± 48 (2–419), and 28 ± 12 (0–105) per slide, respectively. Significant differences were observed in the counts of BM-MK between patients who achieved a clinical response (CR + PR) and those who did not (NR; p = 0.007). Patients in the NR group exhibited fewer BM-MK compared with those in the CR and PR groups (p = 0.017 and p = 0.006, respectively). A receiver-operation characteristic analysis identified that a cutoff value of BM-MK counts at 20 performed pretty well in discriminating patients with differential responses to immunotherapy, with sensitivity and specificity and area under the curve of 88%, 70%, and 0.798, respectively.

Conclusion.

BM-MK count may serve as a good predicting factor for immunotherapeutic response in patients with SLE with severe TP. Patients with BM-MK counts < 20 per slide tend to exhibit poor clinical response.

Features associated with hematologic abnormalities and their impact in patients with systemic lupus erythematosus: Data from a multiethnic Latin American cohort

OBJECTIVE

To examine hematological manifestations' correlates and their impact on damage accrual and mortality in SLE patients from the multiethnic, Latin American, GLADEL cohort.

METHODS

In patients with recent SLE diagnosis (≤2 years), the association between follow-up hematological manifestations (per ACR criteria) and socio-demographic and clinical variables was examined by univariable and multivariable logistic regressions; their impact on damage accrual and mortality was examined by Poisson and Cox proportional-hazards regression analyses, respectively.

RESULTS

Of 1437 patients, 948 (66.0%) developed ≥1 hematological manifestation [5.5% hemolytic anemia (AHA), 16.3% thrombocytopenia, and 56.4% lymphopenia] over 4.3 (3.3) follow-up years. Younger age, Mestizo ethnicity, hematologic disorder (at/or before SLE diagnosis), and first damage recorded were associated with hematological manifestations while antimalarials were negatively associated. AHA (at/or before SLE diagnosis), anti-Sm, and anti-RNP antibodies were associated with subsequent AHA occurrence while musculoskeletal involvement was negatively associated. Thrombocytopenia (at/or before SLE diagnosis), AHA, anti-phospholipid antibodies (aPLs), anti-SSA/Ro, anti-SSB/La antibodies, and first damage recorded were associated with later thrombocytopenia occurrence. Lymphopenia (at/or before SLE diagnosis), younger age at diagnosis, Mestizo ethnicity, having medical insurance, and first damage recorded were associated with subsequent lymphopenia occurrence while antimalarials and azathioprine treatment were negatively associated. AHA was associated with damage accrual and mortality after adjusting for variables known to affect these outcomes.

CONCLUSIONS

Mestizo ethnicity and early hematological manifestations are risk factors for their subsequent occurrence while antimalarials have a protective effect. The associations between AHA and aPLs and thrombocytopenia were corroborated. AHA contributes independently to damage accrual and diminished survival.

Thrombopoietin levels in systemic lupus erythematosus are linked to inflammatory cytokines, but unrelated to thrombocytopenia or thrombosis

BACKGROUND

Thrombopoietin (TPO) is a liver-produced protein that drives megakaryocyte maturation. TPO regulates platelet production and can increase platelet and endothelial reactivity. We investigated the relationship between TPO and the occurrence of thrombocytopenia and thrombosis in patients with systemic lupus erythematosus (SLE).

METHODS

We undertook a cohort study of SLE patients (n = 98) with clinical data collected simultaneously with sampling for TPO, inflammatory cytokines and autoantibody detection. TPO levels were measured by sandwich ELISA with patients with rheumatoid arthritis (RA) (n = 100) and controls (n = 79) as comparators. Disease associations were evaluated using non-parametric methods.

RESULTS

TPO levels in SLE (median 8 pg/ml, mean 326, range 8992) were moderately increased compared with RA (median 8 pg/ml, mean 100, range 1659, p = 0.07) and controls (median 8, mean 94, range 2088, p = 0.1). Among SLE patients, TPO levels did not correlate with platelet count or levels of antiphospholipid antibodies. The prevalence of thrombocytopenic episodes, thrombotic events or active disease was not increased in patients with high TPO levels. TPO levels correlated with MIP-1α (Rs 0.56, p < 0.001), IL6 (Rs 0.26, p = 0.02) and IL4 (Rs 0.29, p = 0.01), and inversely correlated to C4 (Rs -0.23, p = 0.04). MIP-1α was the strongest independent predictor of increased TPO levels.

CONCLUSION

TPO levels are elevated in 20% of patients, but are not closely related to the occurrence of thrombocytopenia or thrombosis in SLE. MIP1-alpha is the main factor driving higher TPO levels among patients with SLE, likely through its inhibitory effect on megakaryocyte function.

Assessment of immunogenicity of romiplostim in clinical studies with ITP subjects

Romiplostim is an Fc-peptide fusion protein that activates intracellular transcriptional pathways via the thrombopoietin (TPO) receptor leading to increased platelet production. Romiplostim has been engineered to have no amino acid sequence homology to endogenous TPO. Recombinant protein therapeutics can be at a risk of development of an antibody response that can impact efficacy and safety. Hence, a strategy to detect potential antibody formation to the drug and to related endogenous molecules can be useful. The immunogenicity assessment strategy involved both the detection and characterization of binding and neutralizing antibodies. The method for detection was based on a surface plasmon resonance biosensor platform using the Biacore 3000. Samples that tested positive for binding antibodies in the Biacore immunoassay were then tested in a neutralization assay. Serum samples from 225 subjects with immune thrombocytopenic purpura (ITP) dosed with romiplostim and 45 ITP subjects dosed with placebo were tested for romiplostim and TPO antibodies. Prior to romiplostim treatment, 17 subjects (7%) tested romiplostim antibody positive and 12 subjects (5%) tested TPO antibody positive for pre-existing binding antibodies. After romiplostim exposure, 11% of the subjects exhibited binding antibodies against romiplostim and 5% of the subjects with ITP showed binding antibodies against TPO. The antibodies against romiplostim did not cross-react with TPO and vice versa. No cases of anti-TPO neutralizing antibodies were detected in romiplostim-treated subjects. The incidence of anti-romiplostim neutralizing antibodies to romiplostim was 0.4% (one subject); this subject tested negative at the time of follow-up 4 months later. No impact on platelet profiles were apparent in subjects that had antibodies to romiplostim to date. In summary, administration of romiplostim in ITP subjects resulted in the development of a binding antibody response against romiplostim and TPO ligand. One subject developed a neutralizing antibody response to romiplostim that impacted the platelet counts of this subject. No neutralizing antibodies to endogenous TPO were observed.

Suspects in the tale of lupus-associated thrombocytopenia

Immunologically mediated thrombocytopenia is a frequent clinical manifestation in patients with systemic lupus erythematosus (SLE). Autoantibodies targeting platelet membrane glucoproteins have a central role in peripheral platelet destruction. Autoantibodies against thrombopoietin are also present in about one-third of patients, but their pathogenetic role is obscure. Thirty-eight serum samples from SLE patients were tested for anti-platelet antibodies, anti-thrombopoietin antibodies and levels of circulating thrombopoietin. Bone marrow histology was also assessed. Thirty-nine per cent of sera displayed anti-thrombopoietin antibodies and 29% had circulating anti-platelet antibodies. Anti-thrombopoietin antibodies were associated with lower thrombopoietin concentrations, and lower mean platelet values in long-term follow-up. Anti-platelet antibodies were present in about 40% of thrombocytopenic and non-thrombocytopenic individuals but were absent in patients who had recovered from thrombocytopenia, supporting their pathogenetic role. Both autoantibodies were absent in control sera from patients with rheumatoid arthritis and primary Sjögren's syndrome. Decreased bone marrow cellularity, normal or low number of hypolobulated, pyknotic megakaryocytes and stromal alterations were prominent findings in thrombocytopenic SLE patients, suggesting a defect in megakaryopoiesis. These findings were not evident in specimens from patients with idiopathic thrombocytopenic purpura who had increased megakaryocytes, normal cellularity and absence of stromal alterations. In conclusion, peripheral destruction due to platelet autoantibodies, anti-thrombopoetin antibodies, lower effective circulating thrombopoetin and impaired compensatory response due to bone marrow damage interact in SLE and thrombocytopenia ensues.

Prospective screening of 205 patients with ITP, including diagnosis, serological markers, and the relationship between platelet counts, endogenous thrombopoietin, and circulating antithrombopoietin antibodies

Immune thrombocytopenia purpura (ITP) is characterized by destruction of circulating platelets and the presence of antiplatelet antibodies. Many of the current immunomodulatory therapies act by reducing platelet destruction and usually do not have a lasting effect. This prospective, exploratory study characterized patients with ITP by identifying their demographic and comorbid clinical factors, use of treatments, serologic markers of autoimmunity, and possible relationships between platelet counts, concentrations of endogenous thrombopoietin (eTPO), and the presence of circulating anti-TPO antibodies. Data including medical history and laboratory evaluations were collected at a single patient visit on 205 patients (19 children, 186 adults). Reported histories revealed a 5% rate of thrombotic/ischemic events. Autoimmune markers including direct antiglobulin test and antinuclear antibodies were found more frequently than in the normal population; antiplatelet antibody testing was not done. eTPO concentrations were comparable to concentrations found in healthy volunteers. Our study confirmed that no significant inverse correlation occurred between circulating concentrations of eTPO and platelet counts in patients with ITP (Spearman r = -0.15). Two of the 205 patients tested (1%) had neutralizing activity of recombinant human TPO in a biological assay; however, this activity was confirmed to be anti-TPO antibody in only 1 patient.