Rituximab for management of refractory pregnancy-associated immune thrombocytopenic purpura

Rituximab as a treatment for refractory immune thrombocytopenia during pregnancy

Immune thrombocytopenia (ITP) is most common in women during their reproductive years. When a low platelet count occurs for the first time during pregnancy, the differential diagnosis includes pregnancy-specific conditions. Although ITP is the most common cause of thrombocytopenia early in pregnancy, pregnancy-related thrombocytopenia develops mainly in late gestation. As maternal and neonatal outcomes are usually favourable, ITP per se is not a contraindication for pregnancy. We report the case with a literature review of patient with ITP, whose diagnosis was established in early pregnancy. This condition was refractory to first-line treatments, such as high-dose steroids and intravenous immunoglobulin and other splenectomy-sparing approaches, as rituximab, having the control been reached on the third trimester after splenectomy. Although not effective in this case, we still believe that rituximab should be considered before surgery during pregnancy.

The many facets of immune-mediated thrombocytopenia: Principles of immunobiology and immunotherapy

Immune thrombocytopenia (ITP) is a rare autoimmune condition, due to peripheral platelet destruction through antibody-dependent cellular phagocytosis, complement-dependent cytotoxicity, cytotoxic T lymphocyte-mediated cytotoxicity, and megakaryopoiesis alteration. This condition may be idiopathic or triggered by drugs, vaccines, infections, cancers, autoimmune disorders and systemic diseases. Recent advances in our understanding of ITP immunobiology support the idea that other forms of thrombocytopenia, for instance, occurring after immunotherapy or cellular therapies, may share a common pathophysiology with possible therapeutic implications. If a decent pipeline of old and new agents is currently deployed for classical ITP, in other more complex immune-mediated thrombocytopenic disorders, clinical management is less harmonized and would deserve further prospective investigations. Here, we seek to provide a fresh overview of pathophysiology and current therapeutical algorithms for adult patients affected by this disorder with specific insights into poorly codified scenarios, including refractory ITP and post-immunotherapy/cellular therapy immune-mediated thrombocytopenia.

Recombinant human thrombopoietin therapy for primary immune thrombocytopenia in pregnancy: a retrospective comparative cohort study

BACKGROUND

Treatment options for pregnant women with immune thrombocytopenia (ITP) who do not respond to first-line treatment are limited. Few studies have reported the use of recombinant human thrombopoietin (rhTPO) for this subset of patients.

AIMS

To investigate the efficacy and safety of rhTPO in ITP during pregnancy and determine obstetric outcomes and predictors of treatment response.

METHODS

From July 2013 to October 2022, the data of 81 pregnant women with ITP and a platelet count < 30 × 109/L who did not respond to steroids and/or intravenous immunoglobulin were retrospectively analysed. Of these patients, 33 received rhTPO treatment (rhTPO group) while 48 did not (control group). Baseline characteristics, haematological disease outcomes before delivery, obstetric outcomes, and adverse events were compared between groups. In the rhTPO group, a generalised estimating equation (GEE) was used to investigate the factors influencing the response to rhTPO treatment.

RESULTS

The baseline characteristics were comparable between both groups (P > 0.05, both). Compared with controls, rhTPO patients had higher platelet counts (median [interquartile range]: 42 [21.5-67.5] vs. 25 [19-29] × 109/L, P = 0.002), lower bleeding rate (6.1% vs. 25%, P = 0.027), and lower platelet transfusion rate before delivery (57.6% vs. 97.9%, P < 0.001). Gestational weeks of delivery (37.6 [37-38.4] vs 37.1 [37-37.2] weeks, P = 0.001) were longer in the rhTPO group than in the control group. The rates of caesarean section, postpartum haemorrhage, foetal or neonatal complications, and complication types in both groups were similar (all P > 0.05). No liver or renal function impairment or thrombosis cases were observed in the rhTPO group. GEE analysis revealed that the baseline mean platelet volume (MPV) (odds ratio [OR]: 0.522, P = 0.002) and platelet-to-lymphocyte ratio (PLR) (OR: 1.214, P = 0.025) were predictors of response to rhTPO treatment.

CONCLUSION

rhTPO may be an effective and safe treatment option for pregnancies with ITP that do not respond to first-line treatment; it may have slightly prolonged the gestational age of delivery. Patients with a low baseline MPV and high baseline PLR may be more responsive to rhTPO treatment. The present study serves as a foundation for future research.

A Systematic Review of the safety of non-TNF inhibitor biologic and targeted synthetic drugs in rheumatic disease in pregnancy

INTRODUCTION

Despite increasing evidence to support safe use of tumour necrosis factor inhibitors (TNFi) and other biologic disease modifying anti-rheumatic drugs (bDMARDs) during pre-conception/pregnancy, there remains a paucity of evidence regarding the safety and compatibility of other non-TNFi and novel targeted synthetic (ts)DMARDs during pre-conception/pregnancy. Therefore, we conducted a systematic review to determine the compatibility of these drugs in pre-conception, during pregnancy and post-partum period.

METHOD

Databases including; EMBASE, Pubmed (MEDLINE), and Cochrane were searched up to 23rd October 2020 to find relevant peer-reviewed papers, using keywords including; rheumatic disease, pregnancy, conception/pre-conception, lactation/breastfeeding, childhood and vaccination/infection, and commonly prescribed non-TNFi drugs and tsDMARDs.

RESULTS

Our search yielded 1483 papers that were screened independently by two authors, and 109 full-text papers were eligible for final analysis. These studies reported 1291 maternal pregnancies exposed to non-TNFi bDMARDs and tsDMARDs with known outcomes, including 721 live births, 219 spontaneous miscarriages and 27 congenital abnormalities. Paternal exposures in 174 pregnancies had reassuring outcomes. A total of 48 breast-fed infants were exposed to non-TNFi bDMARDs and no adverse events reported upon long-term follow-up. Fifteen infants exposed to bDMARDs received normal vaccination regimes, including live vaccines, and had normal developmental outcomes, without any complications or infections.

CONCLUSION

Overall, the findings are reassuring and do not suggest a cause for any major concerns or an increased risk of adverse pregnancy outcomes for maternal or paternal exposures to non-TNFi bDMARDs or tsDMARDs. There were no major concerns for breastfeeding exposures to non-TNFi bDMARDs.

Immunosuppressive Treatment in Antiphospholipid Syndrome: Is It Worth It?

The antiphospholipid syndrome (APS) is characterized by the development of venous and/or arterial thrombosis and pregnancy morbidity in patients with persistent antiphospholipid antibodies (aPL). Catastrophic antiphospholipid syndrome (CAPS) is a life-threatening form of APS occurring in about 1% of cases. Lifelong anticoagulation with vitamin K antagonists remains the cornerstone of the therapy for thrombotic APS, but frequently the use of anticoagulation may be problematic due to the increased risk of bleeding, drug interactions, or comorbidities. Immunosuppressant drugs are widely used to treat several autoimmune conditions, in which their safety and effectiveness have been largely demonstrated. Similar evidence in the treatment of primary APS is limited to case reports or case series, and studies on a large scale lack. Immunomodulatory drugs may be an emerging tool in managing such particular situations, like refractory obstetrical complications, CAPS, or so-called APS non-criteria manifestations. In addition, immunomodulatory drugs may be useful in patients experiencing recurrent thromboembolic events despite optimized anticoagulant therapy. We did a comprehensive review of literature analyzing the possible role of immunomodulation in primary APS to provide a broad overview of potentially safe and effective target treatments for managing this devastating disease.

HOW Collaborative position paper on the management of thrombocytopenia in pregnancy

Thrombocytopenia in pregnancy is a common occurrence, affecting up to 10% of women by the time of birth. These recommendations aim to provide pragmatic guidance on the investigation, diagnosis and management of thrombocytopenia in pregnancy; including safety of neuraxial anaesthesia and precautions required for birth. Management of neonatal thrombocytopenia is also addressed. The authors are clinicians representing haematology, obstetric medicine, maternal-fetal medicine, and anaesthesia. Each author conducted a detailed literature review then worked collaboratively to produce a series of unanimous recommendations. The recommendation strength is limited by the lack of high-quality clinical trial data, and represents level C evidence.

Multidrug Therapy for Refractory Immune Thrombocytopenia in Pregnancy

BACKGROUND

Severe immune thrombocytopenia complicating pregnancy may require treatment beyond first-line medications (intravenous immunoglobulins or corticosteroids), but there is a paucity of literature on the use of such second-line agents in pregnancy.

CASE

The patient is a 29-year-old woman with early-onset severe immune thrombocytopenia at 13 weeks of gestation. Maternal platelet counts reached a nadir of less than 5×10/L. The thrombocytopenia persisted despite first-line medications. Romiplostim, rituximab, and azathioprine were added to the therapeutic regimen. Platelet counts eventually stabilized at greater than 150×10/L before delivery. After delivery at term, the neonate had transient B-cell suppression, which was presumed to be secondary to rituximab, but was otherwise doing well and meeting all milestones at 7 months of age.

CONCLUSION

The addition of second-line agents was associated with sustained elevation in maternal platelet counts and may have obviated the need for splenectomy.

Rituximab and immune thrombocytopenia in adults: The state of knowledge 20 years later

Rituximab has been used for immune thrombocytopenia (ITP) for almost 20 years and is now considered a valid off-label second-line treatment. About 60% to 70% of patients with ITP show initial response to rituximab, but in half of these patients, the disease will eventually relapse. Therefore, in 30% of patients with persistent or chronic ITP, one course of rituximab at 375 mg/m²/week for 4 weeks or 2 fixed 1000-mg rituximab infusions allows for a sustained response rate at 5 years. Unfortunately, to date, no robust predictor of long-term sustained response has been found to assist the physician in deciding to treat with rituximab on an individual basis, and the choice of rituximab or another second-line treatment must be individualized and shared with the patient. Retreatment with rituximab has been found efficient, with a similar or higher magnitude and duration of response in most patients. Rituximab is usually well tolerated, with mainly mild and easily manageable infusion-related adverse events. Severe infections are uncommon, including in the long-term, and occur in patients with at least another contributing factor in more than two thirds. Several issues remain to be resolved. Indeed, head-to-head comparisons with other and new treatments in ITP and robust predictors of long-term response are urgently needed to better determine the position of rituximab in the therapeutic armamentarium for adult ITP. Additionally, the place of combination therapies, maintenance therapy with rituximab and rituximab in newly-diagnosed ITP deserve additional studies.

Clinical effect and safety evaluation of different dosage of Rituximab combined with Cyclophosphamide in treatment of refractory immune Thrombocytopenia

Objective:

To discuss clinical effect of different dosage of rituximab combined with cyclophosphamide in treatment of refractory immune thrombocytopenia (rITP).

Method:

This study was conducted at Department of Hematopathology in XX Hospital from January 2016 to January 2018. In this study. Seventy-eight patients with rITP were selected as the objects, divided into observation group (39 cases) and control group (39 cases) according to random number table. Patients in the control group were treated with conventional rituximab and cyclophosphamide, while the observation group received low-dose rituximab. The same amount of cyclophosphamide was used in the two groups. The statistics of clinical effect, recurrence rate, untoward effect and Laboratory inspection of both groups were made before and after the treatment.

Results:

Compared with the control group, the total occurrence rate of side effects in the observation group decreased significantly; the level of IgM and CD20⁺ in the observation group also decreased significantly, while. The level of IgA, IgG, CD3+ and CD4+ rose significantly (P<0.05). The differences in the level of Th1, TNF-a, IL-18 and Sc5b-9 had statistical significance before and after the treatment (P<0.05).

Conclusion:

Rituximab combined with cyclophosphamide has the definite curative effect on rITP. The small dosage of rituximab combined with cyclophosphamide has higher clinical safety in the treatment.

Use of Rituximab in NHL Malt Type Pregnant in I° Trimester for Two Times

Administration of rituximab, one of the basic drugs for the therapy of B-cell lymphoproliferative diseases, during pregnancy has been suspected to cause developmental fetal events, particularly if given during the first trimester of pregnancy. Therefore, use in pregnancy is not permitted. Howe ver, several cases of pregnant women being treated with rituximab are reported herein; an exception is often made in cases with grave illness. We describe an exceptional case of a woman with non-Hodgkin lymphoma of the mucosa-associated lymphoid tissue type where rituximab was given as a single agent without interruption during two consecutive pregnancies. This case can certainly supply important indications on the safety of rituximab.

A case of successful pregnancy following multidrug treatment including rituximab and intravenous immunoglobulin for primary antiphospholipid antibody syndrome refractory to conventional treatment

Antiphospholipid antibody syndrome (APS) is defined by the presence of clinical symptoms caused by antiphospholipid antibodies. When APS occurs during pregnancy, it is conventionally treated with low-dose aspirin or heparin. In cases refractory to conventional treatment, intravenous immunoglobulin (IvIg) is sometimes added. We present the case of an APS patient with severe thrombocytopenia who experienced a successful pregnancy after treatment that included intravenous rituximab and IvIg. As far as we know, this is the first report demonstrating a positive pregnancy outcome in this context. Physicians may consider prescribing not only IvIg but also rituximab during the first trimester of pregnancy in APS patients with severe obstetrical complications and thrombocytopenia refractory to conventional treatment.

IL-10 producing B cells rescue mouse fetuses from inflammation-driven fetal death and are able to modulate T cell immune responses

Understanding the mechanisms leading to fetal death following maternal subclinical infections is crucial to develop new therapeutic strategies. Here we addressed the relevance of IL-10 secreting B cells (B10) in the maintenance of the immune balance during gestation. µMT females lacking mature B cells presented normal pregnancies, although their fetuses were smaller and their Treg pool did not expand as in B cell sufficient controls. Pregnant µMT females were more susceptible to LPS despite having less Treg; their fetuses died at doses compatible with pregnancy in WT animals. Adoptive transfer of IL-10 negative B effector cells or B cells from IL-10 deficient mice did not modify this outcome. The transfer of B10 cells or application of recombinant murine IL-10 reduced the fetal loss, associated with a normalization of Treg numbers and cytokine modulation at the feto-maternal interface. B cell-derived IL-10 suppressed the production of IL-17A and IL-6 by T cells and promoted the conversion of naïve cells into Treg. B10 cells are required to restore the immune balance at the feto-maternal interface when perturbed by inflammatory signals. Our data position B cells in a central role in the maintenance of the balance between immunity and tolerance during pregnancy.

Immunosuppressives and biologics during pregnancy and lactation : A consensus report issued by the Austrian Societies of Gastroenterology and Hepatology and Rheumatology and Rehabilitation

An increasing and early-onset use of immunosuppressives and biologics has become more frequently seen among patients with inflammatory bowel diseases (IBD) and rheumatic disorders. Many women in their childbearing years currently receive such medications, and some of them in an interdisciplinary setting. Many questions arise in women already pregnant or wishing to conceive with respect to continuing or discontinuing treatment, the risks borne by the newborns and their mothers and long-term safety. Together with the Austrian Society of Rheumatology and Rehabilitation, the IBD working group of the Austrian Society of Gastroenterology and Hepatology has elaborated consensus statements on the use of immunosuppressives and biologics in pregnancy and lactation. This is the first Austrian interdisciplinary consensus on this topic. It is intended to serve as a basis and support for providing advice to our patients and their treating physicians.

Rituximab - A novel therapy for severe ITP in pregnancy: A case report

Background

Rituximab is a novel second-line agent for the treatment of immune thrombocytopenic purpura. Minimal data exist on the use of rituximab in pregnancy. This case illustrates the successful treatment of severe immune thrombocytopenic purpura diagnosed in pregnancy, refractory to all other medical management.

Case

A 32-year-old nulliparous woman was diagnosed with severe immune thrombocytopenic purpura at the time of booking for antenatal care (platelet level of 13 × 10⁹/L). Standard treatment failed to adequately increase her platelet count. Therapy with rituximab was instituted, and her platelet count rose to normal levels, without side effects, and remained at a normal level throughout the pregnancy. There were no maternal or neonatal ill-effects of rituximab therapy.

Conclusion

Rituximab is potentially a safe treatment option for the management of immune thrombocytopenic purpura in pregnancy with good maternal and neonatal outcome when conventional treatments have been unsuccessful. Research is limited to case reports, and therefore limited information currently exists to guide clinicians.

Rituximab before and during pregnancy: A systematic review, and a case series in MS and NMOSD

OBJECTIVE

To evaluate the safety of rituximab treatment before and during pregnancy in women with MS and neuromyelitis optica spectrum disorders (NMOSDs) who may be at risk of relapses by performing a systematic literature review combined with a retrospective single-center case series.

METHODS

Studies were systematically identified in the PubMed, Google Scholar, and EMBASE using the key terms "pregnancy" and "rituximab"; 22 articles were included for review (>17,000 screened). Then, patients with MS and NMOSD from 1 center (University of California, San Francisco) exposed to rituximab before conception were identified through medical record review.

RESULTS

Systematic review: We identified 102 pregnancies with rituximab use within 6 months of conception: 78 resulted in live births and 12 in spontaneous abortions. Of 54 live births with reported gestational age, 31 occurred at term (37 weeks+) and 2 before 32 weeks. When checked, B-cell counts were low in 39% of newborns and normalized within 6 months. Case series: we identified 11 pregnancies (1 ongoing) in 10 women (7 MS and 3 NMOSD) treated with rituximab within 6 months of conception. All completed pregnancies resulted in term live births of healthy newborns (1 lost to follow-up at term). No maternal relapses occurred before/during pregnancy; 1 occurred postpartum (NMOSD).

CONCLUSION

No major safety signal was observed with rituximab use within 6 months of conception. Beyond the need for monitoring neonatal B cells, these observations support prospectively monitoring a larger patient cohort to determine whether rituximab may safely protect women with MS and NMOSD who are planning a pregnancy against relapses.

Acute Kidney Injury in Pregnancy-specific Disorders

The incidence of acute kidney injury in pregnancy (P-AKI) has declined significantly over the last three decades in developing countries. However, it is still associated with significant fetomaternal mortality and morbidity. The diagnosis of P-AKI is based on the serum creatinine increase. The usual formulas for estimating glomerular filtration rate (GFR) are not validated in this population. The incidence of P-AKI with respect to total AKI cases has decreased in the last three decades from 25% in 1980s to 9% in 2000s at our centre. During the first trimester of gestation, AKI develops most often due to septic abortion or hyperemesis gravidarum. Septic abortion related AKI with respect to total AKI decreased from 9% to 5% in our study. Prevention of unwanted pregnancy and avoidance of septic abortion are keys to eliminate abortion associated AKI in early pregnancy. However, we have not seen AKI on account of hyperemesis gravidarum over a period of 33 years at our center. In the third trimester, the differential diagnosis of AKI in association with pregnancy specific conditions namely preeclampsia/HELLP syndrome, acute fatty liver of pregnancy and thrombotic microangiopathies of pregnancy (P-TMA) is more challenging, because these 3 conditions share several clinical features of thrombotic microangiopathy which makes the diagnosis very difficult on clinical grounds. It is imperative to distinguish these conditions to make appropriate therapeutic decisions. Typically, AFLP and HELLP syndrome improve after delivery of the fetus, whereas plasma exchange is the first-line treatment for pregnancy associated thrombotic microangioathies (P-TMA). We observed that preclampsia/eclampsia is the most common cause of AKI in late third trimester and postpartum periods followed by puerperal sepsis and postpartum hemorrhage. Pregnancy-associated thrombotic microangiopathies (aHUS/TTP) and AFLP are rare causes of AKI during pregnancy in developing countries.

Safety issues of biologics in pregnant patients with rheumatic diseases

The safety of biologic agents during pregnancy is still being investigated. Tumor necrosis factor α (TNF-α) inhibitors are the only well-studied biological drugs in pregnancy; they do not appear to be teratogenic but increase the risk of infection after birth when given in late pregnancy. The long-term effects in exposed children are, at present, unknown. An increased risk of infection is a concern for all biologics and the risk increases further should combination with glucocorticoids be necessary. Experiences with rituximab, abatacept, anakinra, tocilizumab, and belimumab in pregnancy are limited. These drugs should be avoided during pregnancy or used only when no other option is available for treatment of serious maternal disease.

Biologic therapies and pregnancy: the story so far

Biologic therapies have revolutionized treatment outcomes for patients with inflammatory arthritis. However, there remains a concern regarding their safety during conception, pregnancy and breastfeeding. Data on the safety of these treatments are largely limited to uncontrolled case reports. Collective evidence from many hundreds of pregnancies in inflammatory arthritis and IBD have suggested that exposure to anti-TNF therapies at the time of conception or during the first trimester does not result in an increased risk of adverse pregnancy and fetal outcomes. Monoclonal antibodies, and to a lesser extent recombinant fusion proteins, do cross the placenta during the second and third trimester and are functional in the fetus, as evidence by lymphopaenia reported at birth in children exposed to rituximab in utero. In addition, live vaccines should be avoided in children with in utero exposure to biologics for at least the first 6 months of life. The longer-term effects of in utero exposure remain unknown. Studies suggest that many of these drugs do enter breast milk in small amounts, but the extent to which they are absorbed by the infant is less clear. Limited reports have not suggested adverse pregnancy outcomes in women whose partners were exposed to anti-TNF therapies or rituximab at the time of conception. Data on other biologic therapies, including anakinra, abatacept and tocilizumab, in both men and women remain extremely limited.

B-cell depletion therapy and pregnancy outcome in severe, refractory systemic autoimmune diseases

OBJECTIVE

To study the pregnancy outcome following Rituximab treatment before conception in patients with refractory autoimmune rheumatic diseases.

METHODOLOGY

Five women with systemic lupus erythematosus (SLE) and 1 woman with ANCA positive vasculitis fulfilling the respective ACR classification criteria were studied retrospectively when they became pregnant following rituximab treatment for refractory disease. Rituximab was given as a 1 g infusion together with 500 mg Methylprednisolone, on day 1 and day 15 after written informed consent.

RESULTS

The median age was 34 (range 32-39) years and median disease duration was 10 (range 5-16) years. All the patients achieved complete B-cell depletion < 1 cell/μL at 1 month and <5 cells/μL at 6 months with prolonged B-cell depletion. Four women had successful pregnancies with median gestational age of 38 (range 31-40) weeks; median weight of the new born was 3.25 (range1.17-3.3) kg with no documented adverse neonatal events. One patient with lupus nephritis (LN) had a premature delivery and increasing proteinuria in the third trimester. One other patient with LN had a premature delivery and the new born had oesophageal atresia.

CONCLUSION

We report a child with oesophageal atresia born to a mother with lupus nephritis who had received Rituximab 12 months prior to conception, while four other pregnancies in women with SLE resulted in morphologically normal children. We also describe the first report, to our knowledge, of a successful pregnancy outcome in a woman with granulomatosis with polyangiitis treated with rituximab.

To B or not to B cells-mediate a healthy start to life

Maternal immune responses during pregnancy are critical in programming the future health of a newborn. The maternal immune system is required to accommodate fetal immune tolerance as well as to provide a protective defence against infections for the immunocompromised mother and her baby during gestation and lactation. Natural immunity and antibody production by maternal B cells play a significant role in providing such immunoprotection. However, aberrations in the B cell compartment as a consequence of maternal autoimmunity can pose serious risks to both the mother and her baby. Despite their potential implication in shaping pregnancy outcomes, the role of B cells in human pregnancy has been poorly studied. This review focuses on the role of B cells and the implications of B cell depletion therapy in pregnancy. It highlights the evidence of an association between aberrant B cell compartment and obstetric conditions. It also alludes to the potential mechanisms that amplify these B cell aberrances and thereby contribute to exacerbation of some maternal autoimmune conditions and poor neonatal outcomes. Clinical and experimental evidence suggests strongly that maternal autoantibodies contribute directly to the pathologies of obstetric and neonatal conditions that have significant implications for the lifelong health of a newborn. The evidence for clinical benefit and safety of B cell depletion therapies in pregnancy is reviewed, and an argument is mounted for further clinical evaluation of B cell-targeted therapies in high-risk pregnancy, with an emphasis on improving neonatal outcomes and prevention of neonatal conditions such as congenital heart block and fetal/neonatal alloimmune thrombocytopenia.

Obstetric nephrology: AKI and thrombotic microangiopathies in pregnancy

AKI in pregnancy remains a cause of significant fetomaternal mortality and morbidity, particularly in developing countries. Hypertensive complications of pregnancy (preeclampsia/eclampsia or hemolysis, elevated liver enzymes, and low platelets count syndrome) are the leading cause of AKI in pregnancy worldwide. Thrombotic microangiopathy is another peculiar and devastating cause of AKI in pregnancy. During the last decade, our understanding, and in some cases, our management, of these causes of AKI in pregnancy has dramatically improved. For instance, convincing data have linked pre-eclampsia/eclampsia to an increase in circulating antiangiogenic factors soluble Flt 1 and endoglin, which induce endothelial cell dysfunction, hypertension, and proteinuria. Several distinct pathogenic mechanisms underlying thrombotic microangiopathy, including thrombotic microangiopathy occurring during pregnancy, have been established. Thrombotic microangiopathy, which can present as hemolytic uremic syndrome or thrombotic thrombocytopenic purpura, can be reclassified in four potentially overlapping subtypes: disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 deficiency-related thrombotic microangiopathy, complement alternative pathway dysregulation-related thrombotic microangiopathy, secondary thrombotic microangiopathy (verotoxin and antiangiogenic drugs), and thrombotic microangiopathy of undetermined mechanism. In most cases, pregnancy is only a precipitating factor for thrombotic microangiopathy. Treatment of thrombotic microangiopathy occurring during pregnancy should be tailored to the underlying pathogenic mechanism: (1) restoration of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 serum activity in the setting of thrombotic thrombocytopenic purpura through plasma exchanges and in some cases, B cell-depleting therapy and (2) inhibition of complement alternative pathway activation in atypical hemolytic uremic syndrome using antiC5 blocking antibody (eculizumab).

Diagnosis and management of maternal thrombocytopenia in pregnancy

Thrombocytopenia is a common finding in pregnancy, occurring in approximately 7-10% of pregnancies. It may be a diagnostic and management problem, and has many causes, some of which are specific to pregnancy. Although most cases of thrombocytopenia in pregnancy are mild, and have no adverse outcome for either mother or baby, occasionally a low platelet count may be part of a more complex disorder with significant morbidity and may be life-threatening. Overall, about 75% of cases are due to gestational thrombocytopenia, 15-20% secondary to hypertensive disorders; 3-4% due to an immune process, and the remaining 1-2% made up of rare constitutional thrombocytopenias, infections and malignancies. In this review, a diagnostic approach to investigating thrombocytopenia in pregnancy is presented, together with antenatal, anaesthetic and peri-natal management issues for mother and baby, followed by a detailed discussion on the specific causes of thrombocytopenia and the management options in each case.

Fetal and Neonatal Illnesses Caused or Influenced by Maternal Transplacental IgG and/or Therapeutic Antibodies Applied During Pregnancy

The human fetus is protected by the mother’s antibodies. At the end of the pregnancy, the concentration of maternal antibodies is higher in the cord blood, than in the maternal circulation. Simultaneously, the immune system of the fetus begins to work and from the second trimester, fetal IgM is produced by the fetal immune system specific to microorganisms and antigens passing the maternal-fetal barrier. The same time the fetal immune system has to cope and develop tolerance and T_REG cells to the maternal microchimeric cells, latent virus-carrier maternal cells and microorganisms transported through the maternal-fetal barrier.

The maternal phenotypic inheritance may hide risks for the newborn, too. Antibody mediated enhancement results in dengue shock syndrome in the first 8 month of age of the baby.

A series of pathologic maternal antibodies may elicit neonatal illnesses upon birth usually recovering during the first months of the life of the offspring. Certain antibodies, however, may impair the fetal or neonatal tissues or organs resulting prolonged recovery or initiating prolonged pathological processes of the children.

The importance of maternal anti-idiotypic antibodies are believed to prime the fetal immune system with epitopes of etiologic agents infected the mother during her whole life before pregnancy and delivery.

The chemotherapeutical and biological substances used for the therapy of the mother will be transcytosed into the fetal body during the last two trimesters of pregnancy. The long series of the therapeutic monoclonal antibodies and conjugates has not been tested systematically yet. The available data are summarised in this chapter.

The innate immunity plays an important role in fetal defence. The concentration of interferon is relative high in the placenta. This is probably one reason, why the therapeutic interferon treatment of the mother does not impair the fetal development.