Antiphospholipid antibody-mediated reproductive failure in antiphospholipid syndrome

Cluster analysis of antiphospholipid antibodies-associated adverse pregnancy outcome patients: based on a 13-years cohort study

Antiphospholipid antibodies (aPLs) are the leading causes of adverse pregnancy outcomes (APOs). We conducted cluster analysis to identify distinct phenotypes among aPLs-associated APOs patients. This approach aims to facilitate risk stratification and improve pregnancy outcomes for obstetric APS. This was a retrospective study of persistent aPLs positive women cohort in Peking Union Medical College Hospital. Baseline demographic characteristics, clinical manifestation, previous APOs and antibodies profiles were included for hierarchical cluster analysis. Placentae from portions of patients were collected and performed the histopathologic diagnoses. Four clusters among 209 patients with 477 pregnancies were identified. Cluster 1 comprised patients with triple aPLs positivity and demonstrates a high incidence of gestational hypertension (34.92%, P < 0.05) and preterm delivery (20.63%, P < 0.05). Patients in cluster 2 were characterized by lupus anticoagulant (LA) positivity, with high risk of whole gestational APOs. Cluster 3 included patients with isolated aPLs-IgM isotype combined with early miscarriage (60.92%, P = 0.016). Patients in cluster 4 majorly presented aPLs-IgG isotype combined with placenta insufficiency (22.73%). During the follow-up, the live birth rate in cluster 1 and 2 was only 69.20%. Placenta pathology revealed the most severe impairment within cluster 1, whereas clusters 3 and 4 exhibited relatively milder damage. By cluster analysis, we identified four clinical subtypes of aPLs-associated APOs patients. Patients with triple antibodies or high-risk lupus characteristics were prone to occurred gestational hypertension and premature delivery. Isolated LA or aCL/aβ2GPI positivity were found to be more frequently associated with early-stage fetal loss.

Glucocorticoids Improve the Pregnancy Rate and Outcome in Women With Unexplained Positive Autoantibodies: A Systematic Review and Meta-Analysis

The effect of glucocorticoid therapy on women with unexplained positive autoantibodies is under debate. This systemic review and meta-analysis were performed to evaluate whether glucocorticoid administration can improve the pregnancy outcome of this population. Relevant publications were searched from databases, and a total of seven prospective and retrospective cohort studies that investigated the effects of glucocorticoid administration on women with unexplained positive autoantibodies, were included. The outcomes of our systematic review and meta-analysis were measured in terms of risk ratios (RR) with 95% confidence intervals (CI) using fixed or random effect models. We found that glucocorticoid treatment improved the clinical pregnancy rate (RR 2.19, 95% CI 1.64–2.92) and live birth rate (RR 1.92, 95% CI 1.17–3.16), especially when glucocorticoid administration was started before pregnancy (clinical pregnancy rate: RR 2.30, 95% CI 1.58–3.34; live birth rate: RR 2.30, 95% CI 1.58–3.34). However, no effect of glucocorticoids on the miscarriage rate was found (RR 0.75, 95% CI 0.55–1.02) regardless of the time of drug administration. Our systematic review and meta-analysis support the rational use of glucocorticoids in women with unexplained positive autoantibodies.

Antiphospholipid antibodies in women with recurrent embryo implantation failure: A systematic review and meta-analysis

OBJECTIVE

Antiphospholipid antibodies (aPL) are related to poor pregnancy outcomes, but their effect on embryo implantation is unclear. We aimed to assess the prevalence of different aPL in women with recurrent implantation failure (RIF).

METHODS

We searched studies in PubMed (MEDLINE), Scopus and Cochrane Library. Quality of studies was scored by the Newcastle-Ottawa Scale and risk of bias assessment by items described in RevMan5 software. Statistical analyses were made using random-effects model and presented as pooled Odds Ratio (OR), 95% confidence interval (CI). Heterogeneity was assessed by I²% and D²%.

RESULTS

This systematic review and meta-analysis included 17 studies and showed a high degree of variability in aPL positivity in RIF. In the latter, the risk of bias assessment suggested unclear bias on study performance with a median sample size and interquartile range for RIF patients and fertile women of 96 (57-417) and 100 (60.5-202.5), respectively. Among the criteria aPL, IgG anticardiolipin autoantibodies (OR 5.02, 95% CI [1.95, 12.93]) were associated with RIF. Within the non-criteria aPL, anti-β2 glycoprotein I-IgA (OR 64.8, 95% CI [9.74, 431.0]), and antiphosphatidylglycerol-IgG and IgM (OR 10.74, 95% CI [5.25, 22.0]; OR 4.26, 95% CI [1.76,10.31]; respectively) were associated with RIF, too.

CONCLUSIONS

Anticardiolipin-IgG is a prevalent autoantibody in women with RIF. Three other non-criteria aPL, aβ2GP I-IgA, aPG-IgG and aPG-IgM also present a positive rate in RIF. Overall, these results advise about testing them as indicators of RIF risk in women seeking IVF treatment.

Safety issues and recommendations for successful pregnancy outcome in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) primarily affects women of childbearing age. One of the major changes in SLE focuses on the timing of a successful pregnancy. In the past, pregnancy was strongly discouraged in SLE, especially in the presence of risk factors such as nephritis, use of immunosuppressive therapies, or positivity of specific autoantibodies such as anti-phospholipids and anti-Ro/SSA, La/SSBA. Thanks to our better knowledge on the disease and management, pregnancy success rates in SLE patients have significantly improved care by the a multidisciplinary team which fosters a successful pregnancy with minimal complications for the mother and fetus when the disease is inactive or in remission. This approach is based on a counseling phase before pregnancy, to assess SLE activity phase, specific medications, risk factors, and continues through pregnancy and lactation with significantly improved pregnancy outcomes. Further, we can now better define the risk of disease flares during pregnancy based on a better understanding of the changes in maternal immunity and its relationship with SLE-associated autoimmunity and chronic inflammation. There is wide consensus that women with SLE can have successful pregnancies as long as conception is planned in a phase of inactive disease, and when the patient is closely managed by a rheumatologist, high-risk OB/GYN, neonatologist, and other medical specialists as indicated. Preconception counseling is essential to assess the risk of both fetal and maternal complications as well as identify life-threatening contraindications. Particular attention should be used in those SLE cases that have nephritis, APS or positivity for aPL, pulmonary hypertension, and positive anti-Ro/SSA or anti-La/SSB antibodies. In conclusion, the use of specific guidelines on the management of SLE before and during pregnancy and lactation, and a better understanding of the use of immunosuppressive therapies have significantly increased pregnancy success.

Antiphosphatidylserine/prothrombin Antibodies in Antiphospholipid Syndrome with Intrauterine Growth Restriction and Preeclampsia

OBJECTIVE

Antibodies that recognize the phosphatidylserine/prothrombin complex (antiphosphatidylserine/prothrombin antibodies; aPS/PT) might reveal enhanced thrombotic risk in patients with systemic lupus erythematosus. Little is known about their association with pregnancy complications in the antiphospholipid syndrome (APS).

METHODS

We enrolled 55 patients with APS who were seeking pregnancy in 2 Italian hospitals. Antiphospholipid antibodies (aPL), including anticardiolipin antibodies, anti-β₂-glycoprotein I antibodies, lupus-like anticoagulant, and aPS/PT antibodies were assessed, and the patients were prospectively followed for 24 months.

RESULTS

There were 65% (36/55) of the APS patients who had aPS/PT antibodies. Forty-seven pregnancies were followed, including 33 of aPS/PT+ patients. Forty-one of the 47 patients (87%) who initiated a pregnancy eventually gave birth to a child. The pregnancy duration and the mean newborn weight at delivery were significantly lower in aPS/PT+ than in aPS/PT- patients (33.1 ± 4.7 vs 36.2 ± 3.4 wks of gestation, respectively, and 2058 ± 964 g vs 2784 ± 746 g, respectively, p < 0.05). Late pregnancy complications, including intrauterine fetal death, preterm delivery, preeclampsia, and intrauterine growth restriction (IUGR), were more frequent in aPS/PT+ patients, independent of the therapy. Titers of aPS/PT IgG were significantly inversely correlated with the neonatal weight at delivery. Vascular injury, as reflected by thrombosis, fibrinoid necrosis, ischemic and hemorrhagic areas, and presence of chorangiomas characterized the IUGR placentas in the presence of aPS/PT.

CONCLUSION

The aPS/PT antibodies might represent markers of aPL-related pregnancy complications, IUGR/preeclampsia in particular, and could help identify beforehand patients who may require additional treatment.

Pregnancy Outcome in Women with Obstetric and Thrombotic Antiphospholipid Syndrome-A Retrospective Analysis and a Review of Additional Treatment in Pregnancy

Antiphospholipid syndrome (APS) is associated with pregnancy complications such as recurrent early fetal loss (RFL), fetal death, preeclampsia (PE), and intrauterine growth restriction (obstetric APS/OAPS). Other clinical manifestations are venous and/or arterial thromboses (thrombotic APS/TAPS). The data of 37 pregnancies with OAPS and 37 pregnancies with TAPS were analyzed and compared. Overall, the most frequent APS antibodies (aPl) were LA as well as "triple-positivity"; LA antibodies were significantly more frequent in women with TAPS (67.6 % TAPS vs. 29.7 % OAPS, p < 0.010), whereas "triple-positivity" was significantly more seen in women with OAPS (40.5 % OAPS vs. 13.5 % TAPS, p < 0.010). Adequate therapy has been administered in nearly all pregnancies with TAPS, whereas in 18.9 % of pregnancies with OPS, no therapy has been given at all. One woman in OAPS and four women in TAPS were treated with plasmapheresis and immunoadsorption. There was no significant association between adverse obstetric outcome and therapy. The most frequent pregnancy complications were RFL in the OAPS group (32.4 vs. 13.5 % in TAPS) and PE in the TAPS group (18.9 % in OAPS and TAPS, respectively). The data of our study showed that pregnancies with OAPS and TAPS have a similar rate of pregnancy complications. However, pregnancies with OAPS tend to have rather RFL. Although we were not able to reveal a significant association with adverse obstetric outcome, it seems that the current adequate therapy for APS in pregnancy, consisting of LDA and LMWH, might rather prevent the development of RFL. Additionally, it might be considered to divide the obstetric APS into obstetric APS with early pregnancy complications and obstetric APS with late pregnancy complications. The division into two groups of obstetric APS might facilitate the choice of additional therapy in these women.

ApoE Receptor 2 Mediation of Trophoblast Dysfunction and Pregnancy Complications Induced by Antiphospholipid Antibodies in Mice

OBJECTIVE

Pregnancies in women with the antiphospholipid syndrome (APS) are frequently complicated by fetal loss and intrauterine growth restriction (IUGR). How circulating antiphospholipid antibodies (aPL) cause pregnancy complications in APS is poorly understood. We sought to determine whether the low-density lipoprotein receptor family member apolipoprotein E receptor 2 (ApoER2) mediates trophoblast dysfunction and pregnancy complications induced by aPL.

METHODS

Placental and trophoblast ApoER2 expression was evaluated by immunohistochemistry and immunoblotting. Normal human IgG and aPL were purified from healthy individuals and APS patients, respectively. The role of ApoER2 in aPL-induced changes in trophoblast proliferation and migration and in kinase activation was assessed using RNA interference in HTR-8/SVneo cells. The participation of ApoER2 in aPL-induced pregnancy loss and IUGR was evaluated in pregnant ApoER2(+/+) and ApoER2(-/-) mice injected with aPL or normal human IgG.

RESULTS

We found that ApoER2 is abundant in human and mouse placental trophoblasts and in multiple trophoblast-derived cell lines, including HTR-8/SVneo cells. ApoER2 and its interaction with the cell surface protein β2 -glycoprotein I were required for aPL-induced inhibition of cultured trophoblast proliferation and migration. In parallel, aPL antagonism of Akt kinase activation by epidermal growth factor in trophoblasts was mediated by ApoER2. Furthermore, in a murine passive-transfer model of pregnancy complications of APS, ApoER2(-/-) mice were protected from both aPL-induced fetal loss and aPL-induced IUGR.

CONCLUSION

ApoER2 plays a major role in the attenuation of trophoblast function by aPL, and the receptor mediates aPL-induced pregnancy complications in vivo in mice. ApoER2-directed interventions can now potentially be developed to combat the pregnancy complications associated with APS.

Antibodies to Phosphatidylserine/Prothrombin Complex in Antiphospholipid Syndrome: Analytical and Clinical Perspectives

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombosis and/or pregnancy-related morbidity accompanied by persistently positive antiphospholipid antibodies (aPL). Current laboratory criteria for APS classification recommend testing for lupus anticoagulant as well as IgG and IgM anticardiolipin, and beta-2 glycoprotein I (anti-β2GPI) antibodies. However, there appears to be a subset of patients with classical APS manifestations who test negative for the recommended criteria aPL tests. While acknowledging that such patients may have clinical features that are not of an autoimmune etiology, experts also speculate that these "seronegative" patients may test negative for relevant autoantibodies as a result of a lack of harmonization and/or standardization. Alternatively, they may have aPL that target other antigens involved in the pathogenesis of APS. In the latter, autoantibodies that recognize a phosphatidylserine/prothrombin (PS/PT) complex have been reported to be associated with APS and may have diagnostic relevance. This review highlights analytical and clinical attributes associated with PS/PT antibodies, taking into consideration the performance characteristics of criteria aPL tests in APS with specific recommendations for harmonization and standardization efforts.

Neonatal outcome in pregnant patients with antiphospholipid syndrome

AIMS

The study aim was to evaluate pregnancy outcomes in patients with antiphospholipid syndrome (APS) and to determine which clinical parameters present risk factors for adverse pregnancy outcomes in these patients.

METHODS

The study included 55 patients with APS treated at the Clinic for Ob/Gyn, Clinical Center of Serbia, from 2006 to 2012. The control group consisted of 55 healthy pregnant women. Data regarding previous pregnancies and conception method were registered. Immunological and laboratory tests were performed. Pregnancy outcomes, including miscarriage, intrauterine fetal death, hypertensive disorders, diabetes mellitus, phlebothrombosis, fetal growth restriction, premature delivery, delivery method, perinatal asphyxia, respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis were followed.

RESULTS

The premature delivery rate in APS patients was 31.8%, and pregnancy loss was 18.2%. Significantly more patients with APS had thrombocytopenia, pregnancy losses, intrauterine growth restriction, and perinatal asphyxia compared with the control group. More miscarriages, preterm delivery, lower birth weight, preeclampsia, and IgM anticardiolipin antibody levels significantly correlated with adverse pregnancy outcomes. Although rare, respiratory distress syndrome can also worsen neonatal health status. According to ROC analysis, previous miscarriages correctly explained 66.3% of adverse pregnancy outcome cases. We generated four equations of adverse pregnancy outcome risk factors.

CONCLUSIONS

The most important prognostic factor for pregnancy outcome in APS patients is the number of previous miscarriages. Using appropriate current therapeutic protocol can enable live birth of a healthy newborn in most cases.

Anti-Phosphatidylserine/Prothrombin Antibodies Are Associated with Adverse Pregnancy Outcomes

Objective. To determine the prevalence and clinical association of anti-phosphatidylserine/prothrombin antibodies (aPS/PT) in patients with a history of pregnancy complications relevant to antiphospholipid syndrome (APS). Materials and Methods. Two hundred and eleven patients with a history of (a) three or more consecutive miscarriages before 10th week of gestation (WG) (n = 64), (b) death of a morphologically normal fetus beyond 10th WG (n = 72), (c) premature birth of a morphologically normal neonate before 34th WG due to eclampsia, preeclamsia and placental insufficiency (n = 33), and (d) less than three unexplained consecutive miscarriages before 10th WG (n = 42). Subjects sera were analyzed for lupus anticoagulant (LA), anti-cardiolipin (aCL), anti-β₂-glycoprotein I (anti-β₂GPI), and aPS/PT antibodies. Results. 41/169 (24.3%) of patients were positive for at least one measured aPL. The highest prevalence was found for aPS/PT and aCL (13.0% and 12.4%, resp.) followed by LA (7.7%) and anti-β₂GPI (7.1%). 11/169 with APS-related obstetric manifestations had only aPS/PT. 17.8% of patients were positive for LA or aCL and/or anti-β₂GPI; however when adding the aPS/PT results, an additional 7% of patients could be evaluated for APS. Conclusion. aPS/PT are associated with recurrent early or late abortions and with premature delivery irrespective of other aPL.

Obstetric antiphospholipid syndrome: a recent classification for an old defined disorder

Obstetric antiphospholipid syndrome (APS) is now being recognized as a distinct entity from vascular APS. Pregnancy morbidity includes >3 consecutive and spontaneous early miscarriages before 10weeks of gestation; at least one unexplained fetal death after the 10th week of gestation of a morphologically normal fetus; a premature birth before the 34th week of gestation of a normal neonate due to eclampsia or severe pre-eclampsia or placental insufficiency. It is not well understood how antiphospholipid antibodies (aPLs), beyond their diagnostic and prognostic role, contribute to pregnancy manifestations. Indeed aPL-mediated thrombotic events cannot explain the obstetric manifestations and additional pathogenic mechanisms, such as a placental aPL mediated complement activation and a direct effect of aPLs on placental development, have been reported. Still debated is the possible association between aPLs and infertility and the effect of maternal autoantibodies on non-vascular manifestations in the babies. Combination of low dose aspirin and unfractionated or low molecular weight heparin is the effective treatment in most of the cases. However, pregnancy complications, in spite of this therapy, can occur in up to 20% of the patients. Novel alternative therapies able to abrogate the aPL pathogenic action either by interfering with aPL binding at the placental level or by inhibiting the aPL-mediated detrimental effect are under active investigation.

The autoimmune side of heart and lung diseases

The elevated cardiovascular morbidity in rheumatoid arthritis, systemic lupus erythematosus, and the antiphospholipid syndrome is well known, as well as the pulmonary involvement observed in these conditions and to a major extent in systemic sclerosis. These manifestations constitute a major challenge for clinicians involved in patient management. Moreover, several issues regarding the link between autoimmune rheumatic diseases and cardio pulmonary morbidity remain largely enigmatic. The mechanistic role of certain autoantibodies frequently observed in association with heart and lung diseases or the pathogenetic link between chronic inflammation and the pathways leading to atherosclerosis or pulmonary vascular changes are yet to be elucidated. As such, these questions as well as treatment strategies are of common interest to rheumatologists, immunologist, pulmonologists, and cardiologists and thus call for an interdisciplinary approach. This paradigm has been well established for rare conditions such as the Churg-Strauss syndrome. Nowadays, it seems that this approach should be expanded to encompass more common conditions such as coronary heart disease, pulmonary arterial hypertension or dilated cardiomyopathy. The present issue of Clinical Reviews in Allergy and Immunology addresses the new knowledge and concepts of autoimmune-related cardiopulmonary diseases. The issue derives from the 2010 International Autoimmunity Meeting held in Ljubljana, Slovenia and is thus timely and dedicated to the latest developments in this new multidisciplinary field.

Loss of maternal annexin A5 increases the likelihood of placental platelet thrombosis and foetal loss

Antiphospholipid syndrome is associated with an increased risk of thrombosis and pregnancy loss. Annexin A5 (Anxa5) is a candidate autoantigen. It is not known, however, whether endogenous Anxa5 prevents foetal loss during normal pregnancy. We found significant reductions in litter size and foetal weight in Anxa5-null mice (Anxa5-KO). These changes occurred even when only the mother was Anxa5-KO. A small amount of placental fibrin deposition was observed in the decidual tissues, but did not noticeably differ between wild-type and Anxa5-KO mice. However, immunoreactivity for integrin beta 3/CD61, a platelet marker, was demonstrated within thrombi in the arterial canals only in Anxa5-KO mothers. Subcutaneous administration of the anticoagulant heparin to pregnant Anxa5-KO mice significantly reduced pregnancy loss, suggesting that maternal Anxa5 is crucial for maintaining intact placental circulation. Hence, the presence of maternal Anxa5 minimises the risk of thrombosis in the placental circulation and reduces the risk of foetal loss.

Immunological and biochemical markers in preeclampsia

A basic precondition for the development of preeclampsia is the presence of placental trophoblast cells in the maternal blood circulation. On the other hand, while trophoblast cells are present in the blood of all pregnant women, preeclampsia occurs in only 2-5% of them. Evidently, other factors play a crucial role. The aim of this study was to compare a set of selected immunological factors (anti-cardiolipin autoantibodies, trophoblast-induced cell-mediated immunity, C3 and C4 complement components) and biochemical factors (serum immunoglobulins IgA, IgG, IgM) among three groups of women with uncomplicated pregnancy, gestational hypertension, or preeclampsia. Blood samples were taken 2-12h before delivery. In the preeclampsia group, there was a significantly higher number of women positive for anti-cardiolipin autoantibodies, trophoblast-induced cell-mediated immunity was elevated, serum IgG was elevated and C4 complement component was reduced. We conclude that both elevated autoimmune reactivity and the higher immune reactivity to trophoblast may contribute to the onset of preeclampsia.

The future of autoimmunity

There have been enormous strides in our understanding of autoimmunity. These strides have come under the umbrellas of epidemiology, immunological phenotype and function, disease definitions and classification and especially new therapeutic reagents. However, while these advances have been herculean, there remains enormous voids. Some of these voids include genetic susceptibility and the interaction of genes and environment. The voids include induction of tolerance in preclinical disease and definitions of host susceptibility and responses to the expensive biologic agents. The voids include the so-called clustering of human autoimmune diseases and the issues of whether the incidence is rising in our western society. Other voids include the relationships between microbiology, vaccination, gut flora, overzealous use of antibiotics, and the role of nanoparticles and environmental pollution in either the induction or the natural history of disease. One cannot even begin to address even a fraction of these issues. However, in this special issue, we are attempting to discuss clinical issues in autoimmunity that are not usually found in generic reviews. The goal is to bring to the readership provocative articles that ultimately will lead to improvement in patient care.

Mechanisms and pathophysiology of autoimmune disease

The first textbook on autoimmunity was published by Ian Mackay and McFarland Burnett in 1963. It was the first attempt to summarize existing knowledge on human autoimmunity. Since that time, there have been tens of thousands of experimental papers and numerous textbooks that focus on the diagnosis and treatment of human autoimmunity. There have been at least as many, if not more, directed at similar issues in animal models. Enormous strides have been made not only in diagnosis, but also in the pathophysiology and especially in treatment. We have gone from the era of simple HLA typing to deep sequencing and, more recently, epigenetic analysis. We have gone from the era of white blood cell differentials to detailed lymphoid phenotyping. We have gone from the era of simple antinuclear antibodies to detailed and sophisticated immunodiagnosis with recombinant autoantigens and disease-specific epitopes. We have gone from the era of using only corticosteroids to selective biologic agents. Diseases that were previously considered idiopathic are now very much understood as autoimmune. We are in the era of autoinflammatory reactions and the concept of both innate versus adaptive immunity in mediating immunopathology. In this edition of Clinical Reviews in Allergy and Immunology, we focus on key and cutting-edge issues in the pathophysiology of autoimmunity. The issues are very much oriented and driven by hypothesis, i.e., a prediction of events expected to occur based on observations. It is not meant to be a complete summary of potential mechanisms of autoimmunity, but rather an attempt to accelerate discussion and better understanding. The primary goal is obviously to help our patients with autoimmune disease.

Cutting-edge issues in organ-specific autoimmunity

There have been numerous methods and ways to classify autoimmune diseases. By far, the most traditional has been to separate immune-mediated pathology into organ-specific and organ-non-specific diseases. The classic systemic autoimmune diseases are, of course, rheumatoid arthritis and systemic lupus. The classic organ-specific autoimmune diseases have been autoimmune thyroiditis and autoimmune gastritis. However, as our understanding of the loss of tolerance has expanded, so has the long list of autoimmune diseases. In many cases, the distinction between organ-specific and organ-non-specific or systemic autoimmunity becomes a blur. In this issue, we discuss recent concepts in autoimmune pancreatitis, primary sclerosing cholangitis, Goodpasture's syndrome, myofasciitis, type I diabetes, polymyositis, autoimmune thyroid disease, IgA nephropathy, autoimmune uveitis, and ANCA-associated vasculitis. Common themes on both etiology and effector mechanisms are described throughout these papers with an attempt to provide a cutting-edge overview.

Prolactin’s role in the pathogenesis of the antiphospholipid syndrome

Increased levels of serum prolactin have been reported in patients with various autoimmune diseases and have been associated with lupus disease activity. Currently, there is a lack of data regarding hyperprolactinaemia in patients with the antiphospholipid syndrome. Hence, this study was carried out in order to evaluate the prevalence and clinical significance of hyperprolactinaemia in antiphospholipid syndrome. A total of 172 European patients with antiphospholipid syndrome and 100 geographically and sex-matched healthy controls were included in the study; none had obvious causes of hyperprolactinaemia. All patients underwent clinical assessment for disease manifestations, in addition to laboratory assessment for serum prolactin, antiphospholipid antibodies and some other biomarkers of autoimmune diseases. The tests were performed utilizing the LIAISON® Analyzer (DiaSorin, Sallugia Italy). Hyperprolactinaemia was detected in 21/172 patients with antiphospholipid syndrome and 0/100 controls (p < 0.001). This significant difference was present in both genders and was obvious even after subgrouping the patients into primary and secondary antiphospholipid syndrome. When clinical features were compared, hyperprolactinaemia was associated with reproductive failure, including early and late pregnancy loss (p < 0.05), as well as intrauterine growth retardation (p < 0.05). Hyperprolactinaemia was negatively related to arthralgias, venous thrombosis, pulmonary microthrombosis, pulmonary hypertension in both primary antiphospholipid syndrome and antiphospholipid syndrome secondary to other diseases, and to neurological manifestations in primary antiphospholipid syndrome (p<0.05). The data indirectly imply that prolactin may play a role in the pathogenesis of antiphospholipid syndrome, especially antiphospholipid syndrome-related reproductive failure.