Letter: Autoimmune thrombocytopenia purpura and Hashimoto's thyroiditis

The highs and lows of cyclic thrombocytopenia

Cyclic thrombocytopenia (CTP) is characterized by periodic platelet oscillation with substantial amplitude. Most CTP cases have a thrombocytopenic background and are often misdiagnosed as immune thrombocytopenia with erratically effective treatment choices. CTP also occurs during hydroxyurea treatment in patients with myeloproliferative diseases. While the aetiology of CTP remains uncertain, here we evaluate historical, theoretical and clinical findings to provide a framework for understanding CTP pathophysiology. CTP retains the intrinsic oscillatory factors defined by the homeostatic regulation of platelet count, presenting as reciprocal platelet/thrombopoietin oscillations and stable oscillation periodicity. Moreover, CTP patients possess pathogenic factors destabilizing the platelet homeostatic system thereby creating opportunities for external perturbations to initiate and sustain the exaggerated platelet oscillations. Beyond humoral and cell-mediated autoimmunity, we propose recently uncovered germline and somatic genetic variants, such as those of MPL, STAT3 or DNMT3A, as pathogenic factors in thrombocytopenia-related CTP. Likewise, the JAK2 V617F or BCR::ABL1 translocation that drives underlying myeloproliferative diseases may also play a pathogenic role in hydroxyurea-induced CTP, where hydroxyurea treatment can serve as both a trigger and a pathogenic factor of platelet oscillation. Elucidating the pathogenic landscape of CTP provides an opportunity for targeted therapeutic approaches in the future.

Case report: A case of immune thrombocytopenia combined with Hashimoto's thyroiditis and Helicobacter pylori infection in a child

Immune thrombocytopenia (ITP) is one of the most prevalent acquired bleeding disorders in children, which is primarily characterized by a decrease in platelet count. It can be classified into two subtypes: primary ITP and secondary ITP. The underlying mechanisms causing ITP are complex and not fully comprehended. Helicobacter pylori (H. pylori) infections can lead to ITP and potentially trigger various autoimmune diseases. Furthermore, there is evidence of a correlation between thyroid disease and ITP. In this case report, we describe the case of an 11-year-old patient who presented with ITP, Hashimoto's thyroiditis (HT), and H. pylori infection. Following anti-H. pylori treatment and thyroxine supplementation, the child's platelet count increased compared to the previous count. The limitation of this report is that the platelet count of this child returned to normal after anti-H. pylori and thyroxine supplementation, so we cannot distinguish the effect of anti-H. pylori and thyroxine supplementation on the platelet count in this child. Despite this limitation, we still believe that early screening for thyroid function and H. pylori, as well as prompt eradication of H. pylori, along with thyroxine supplementation, may be beneficial in treating and improving the prognosis of children diagnosed with ITP.

Clinical association between thyroid disease and immune thrombocytopenia

Immune thrombocytopenia (ITP) can coexist with autoimmune thyroid disease. However, the detailed clinical features remain unknown. We retrospectively reviewed 248 patients with newly diagnosed ITP in our institute for whom we had thyroid function data at diagnosis between 2000 and 2019. Of the 248 patients with ITP, 74 patients also had thyroid disease, including 36 with overt thyroid disease (13 Graves' disease and 23 Hashimoto's thyroiditis) and 38 with subclinical thyroid disease (3 hyperthyroidism and 35 hypothyroidism). ITP and thyroid disease were concurrently diagnosed in 54 patients. Female sex and positivity for antinuclear antibodies (ANA) were significantly associated with thyroid diseases. Platelet-associated immunoglobulin G (PAIgG) levels in patients with Graves' disease were higher than those in patients with Hashimoto's thyroiditis. Platelet counts were similar among euthyroid patients and patients with thyroid disease. Thrombopoietin-receptor agonist was administered more frequently in patients with thyroid disease. The cumulative incidences of thrombosis and bleeding and overall survival did not differ between patients with and without thyroid disease. Treatment for thyroid disease in 22 patients improved thrombocytopenia in 21 patients, especially in 4 patients who were not treated for ITP. This study demonstrated that thyroid diseases were commonly found in patients with ITP. Treatment of the underlying thyroid disease may improve thrombocytopenia.

Myasthenia gravis and Werlhof's disease

A case of Werlhof's disease (immune thrombocytopenia) associated with myasthenia gravis is described. The two disorders developed within a few months of each other. The immunological and practical aspects of the association are discussed.

Thyroid disease in patients with idiopathic thrombocytopenia: a cohort study

OBJECTIVES

To estimate the prevalence of the association between thyroid disease and idiopathic thrombocytopenia (ITP), and to examine the effect of treatment of the thyroid condition on platelet count.

DESIGN

Retrospective cohort study performed in a tertiary care center setting. All patients who were diagnosed with ITP by a single provider at the Cleveland Clinic Hematology/Oncology Department between 1988 and 2005 were included.

MAIN OUTCOME

Among the 98 patients, thyroid function tests were available in 80 patients. Of these, 16 (20%) had abnormal thyroid function: 6 had hyperthyroidism and 10 had hypothyroidism. The median interval from the onset of the thyroid or hematological condition (whichever came first) was 84 months (range: 25-612). The autoimmune nature of the thyroid disease was proven in 12 cases (75%). Three patients showed a transient increase in the platelet count after restoring the euthyroid state; however, durable improvement of thrombocytopenia was not encountered.

CONCLUSIONS

The prevalence of hypothyroidism in patients with ITP is higher than in the general population. Based on this observation, routine assessment of thyroid function should be done in patients with ITP. The long-term course of ITP was not influenced by the treatment of the thyroid condition.

Long-term outcome of otherwise healthy individuals with incidentally discovered borderline thrombocytopenia

BACKGROUND

The long-term outcome of individuals with mild degrees of thrombocytopenia is unknown.

METHODS AND FINDINGS

In a prospective study conducted between August 1992 and December 2002, 260 apparently healthy individuals with incidentally discovered platelet counts between 100 x 10(9)/l and 150 x 10(9)/l were monitored for 6 mo to determine whether their condition persisted. The monitoring period was completed in 217 cases, of whom 191 (88%) maintained stable platelet counts. These 191 individuals were included in a long-term follow-up study to gain knowledge of their natural history. With a median time of observation of 64 mo, the thrombocytopenia resolved spontaneously or persisted with no other disorders becoming apparent in 64% of cases. The most frequent event during the study period was the subsequent development of an autoimmune disease. The 10-y probability of developing idiopathic thrombocytopenic purpura (ITP), as defined by platelet counts persistently below 100 x 10(9)/l, was 6.9% (95% confidence interval [CI]: 4.0%-12.0%). The 10-y probability of developing autoimmune disorders other than ITP was 12.0% (95% CI: 6.9%-20.8%). Most of the cases (85%) of autoimmune disease occurred in women.

CONCLUSIONS

Healthy individuals with a sustained platelet count between 100 x 10(9)/l and 150 x 10(9)/l have a 10-y probability of developing autoimmune disorders of 12%. Further investigation is required to establish whether this risk is higher than in the general population and whether an intensive follow-up results in an improvement of prognosis.

Hemostasis and thyroid diseases revisited

Several papers have reported various hemostatic abnormalities in patients with thyroid diseases. In this concise review, the traditional associations between hypercoagulable state and hyperthyroidism and between hypocoagulative state and hypothyroidism are critically revised on the basis of more recent literature data. In particular, we analyze the hemostatic balance (primary hemostasis, coagulation factors and fibrinolytic system) in different thyroid disorders. Although most of the studies published so far include limited numbers of patients and their results are sometimes contradictory, we can conclude that hyperthyroidism is generally accompanied by a hypercoagulable state, whereas the hemostatic profile in hypothyroidism and thyroid cancer depends on the severity of the disease.

Autoimmune thrombocytopenia (AITP) and thyroid autoimmune disease (TAD): overlapping syndromes?

The pathogenesis of thrombocytopenia associated with TAD and the occurrence of overlapping traits between TAD and AITP are still a matter of debate. For this reason, we investigated for the presence and specificity of platelet and thyroid autoantibodies in 18 TAD patients with thrombocytopenia, 19 TAD patients without thrombocytopenia and in 22 patients with primary AITP without clinical signs of TAD. Platelet-associated IgG and/or specific circulating platelet autoantibodies were detected in 83% of patients with TAD and thrombocytopenia, in 10% of patients with TAD without thrombocytopenia and in 86% of patients with primary AITP. The reactivity of serum autoantibodies, assayed by MoAb immobilization of platelet antigens (MAIPA), was directed against platelet glycoproteins Ib and/or IIb/IIIa in 50% of the patients with TAD and thrombocytopenia, as in 46% of the patients with primary AITP. Thyroid autoantibodies were found in 89% of patients with TAD and thrombocytopenia, in 95% of patients with TAD without thrombocytopenia, and in 18% of patients with primary AITP. Thyrotropin (TSH) levels determined in three of four AITP patients with thyroid autoantibodies revealed a subclinical hyperthyroidism in one patient. The present study supports the autoimmune aetiology of thrombocytopenia associated with TAD, since the prevalence and specificity of platelet autoantibodies are similar in TAD and primary AITP. The results indicate also that there exists an overlap between thyroid and platelet autoimmunity with or without clinical manifestations.

Familial association of autoimmune thrombocytopenia and hyperthyroidism

An association between thrombocytopenia and thyrotoxicosis in a single individual is well documented, and the theories for this event include a common immunologic cause or a thyrotoxic-induced decrease in platelet survival. We report the first description of the coexistence of autoimmune thrombocytopenic purpura (AITP) and Graves' disease in several members of the same family, in which four females were thrombocytopenic and two of these were also hyperthyroid. All four patients had high titers of antiplatelet antibodies, and the two hyperthyroid cases were positive for thyroid-stimulating immunoglobulins (TSI). The familial occurrence of two autoimmune disorders is very uncommon, and suggests a genetic etiology. The HLA phenotype was determined and the antigens B8 and DR3, which are reported with high frequency in both diseases, were present in three patients. Although the etiologic cause is still unknown, our findings further support the theory that a genetic predisposition underlies autoimmune disease.

Haemostasis in hypothyroidism

Abnormalities that have been reported for platelet indices and function, coagulation factors and tests, and the fibrinolytic system in hypothyroidism are reviewed. These abnormalities, although usually of limited importance clinically, may occasionally lead to major bleeding episodes and to diagnostic confusion.

Genetic factors predisposing to autoimmune diseases. Autoimmune hemolytic anemia, chronic thrombocytopenic purpura, and systemic lupus erythematosus

Genetic factors predisposing to autoimmune diseases were investigated in 10 families having more than one affected member. Seventy relatives and 23 spouses from two large kindreds (one in whom the proband had autoimmune hemolytic anemia and the other immune thrombocytopenic purpura) were examined for immunologically mediated disorders, autoantibodies, immunoglobulin abnormalities, and HLA genotypes. Significant differences between relatives and spouses were found for immune diseases (21 percent versus 0 percent; p = 0.02), antinuclear antibody titer of 1:80 or more (18 percent versus 0 percent; p = 0.04), single-strand DNA antibodies (18 percent versus 0 percent; p = 0.04), high-titer antinuclear antibody or antibodies to single-strand DNA or both (33 percent versus 0 percent; p = 0.001), and the combined frequencies of immune diseases and serologic abnormalities (44 percent versus 4 percent; p = 0.0004). Similar frequencies were found in 41 relatives from eight families in whom the proband had SLE. Segregation analyses using these abnormalities as genetic traits were most compatible with a Mendelian dominant model. Impressive odds (100:1) against linkage to HLA were calculated.

Idiopathic thrombocytopenic purpura and Graves disease

A 31-year-old black woman was studied who, at the age of 12 years, underwent splenectomy for a bleeding disorder due to idiopathic thrombocytopenic purpura (ITP). More than 20 years after the first signs of her bleeding disorder, the patient developed signs of Graves disease. This condition was treated with 131I with resulting hypothyroidism. The rare combination of ITP and Graves disease was considered to be a manifestation of two separate autoimmune disease. For the second time in the literature, HLA typing was performed in a patient with such a disease combination, and it was found to be of the group A23, A28, and B17. This is different from B8, which is most frequently found in both isolated ITP and Graves disease. Possible racial factors may be involved. It is concluded that more cases of such combined disease need to be studied before possible genetic patterns can be established.