Critical issues and needs in management of primary immunodeficiency diseases in Latin America

Discontinuation of immunoglobulin replacement therapy in patients with secondary antibody deficiency

INTRODUCTION

Secondary immunodeficiency is becoming a greater medical concern as the usage of immunosuppressive and biological treatments has increased. Individuals with certain medical conditions, such as hematological malignancies, can also have secondary immunodeficiency. Immunoglobulin replacement therapy (IGRT), which has been used for decades in inherited or primary immunodeficiency, provides some protection to patients with acquired and predominant antibody deficiency, i.e. secondary antibody deficiency (SAD). However, IGRT is costly, and supplies are limited. Although there are clinical guidelines on when to initiate IGRT, there is no guideline on when to discontinue it.

AREAS COVERED

The authors reviewed existing literature and provided an overview of the current state of knowledge regarding IGRT discontinuation in SAD patients.

EXPERT OPINION

Long-term supplementary immunoglobulin may not be necessary. Although it is possible to successfully transition away from IGRT in individuals with SAD, evidence-based practices are limited. Without clear guidelines and reliable prognostic markers, IGRT discontinuation practices are restricted to clinical judgment. For this reason, additional research should be conducted to identify markers that indicate the recovery of humoral immunity. Furthermore, the derivation and validation of a set of combined clinical and laboratory criteria to allow safe and timely IGRT discontinuation is warranted.

Current state and future perspectives of the Latin American Society for Immunodeficiencies (LASID)

Primary immunodeficiencies (PID) are genetic diseases that affect the immune system and for the last 20 years, the Latin American Society for Immunodeficiencies (LASID) has been promoting initiatives in awareness, research, diagnosis, and treatment for the affected patients in Latin America. These initiatives have resulted in the development of programmes such as the LASID Registry (with 4900 patients registered as of January 2014), fellowships in basic and clinical research, PID summer schools, biannual meetings, and scientific reports, amongst others. These achievements highlight the critical role that LASID plays as a scientific organisation in promoting science, research and education in this field in Latin America. However, challenges remain in some of these areas and the Society must envision additional strategies to tackle them for the benefit of the patients. In June 2013, a group of experts in the field met to discuss the contributions of LASID to the initiatives of PID in Latin America, and this article summarises the current state and future perspectives of this society and its role in the advance of PIDs in Latin America.

Doctors' awareness concerning primary immunodeficiencies in Brazil

BACKGROUND

PIDs are a heterogeneous group of genetic illnesses, and delay in their diagnosis is thought to be caused by a lack of awareness among physicians concerning PIDs. The latter is what we aimed to evaluate in Brazil.

METHODS

Physicians working at general hospitals all over the country were asked to complete a 14-item questionnaire. One of the questions described 25 clinical situations that could be associated with PIDs and a score was created based on percentages of appropriate answers.

RESULTS

A total of 4026 physicians participated in the study: 1628 paediatricians (40.4%), 1436 clinicians (35.7%), and 962 surgeons (23.9%). About 67% of the physicians had learned about PIDs in medical school or residency training, 84.6% evaluated patients who frequently took antibiotics, but only 40.3% of them participated in the immunological evaluation of these patients. Seventy-seven percent of the participating physicians were not familiar with the warning signs for PIDs. The mean score of correct answers for the 25 clinical situations was 48.08% (±16.06). Only 18.3% of the paediatricians, 7.4% of the clinicians, and 5.8% of the surgeons answered at least 2/3 of these situations appropriately.

CONCLUSIONS

There is a lack of medical awareness concerning PIDs, even among paediatricians, who have been targeted with PID educational programmes in recent years in Brazil. An increase in awareness with regard to these disorders within the medical community is an important step towards improving recognition and treatment of PIDs.

Medical awareness concerning primary immunodeficiency diseases in the city of São Paulo, Brazil

OBJECTIVE

To evaluate medical knowledge of primary immunodeficiency in the city of São Paulo (SP).

METHODS

A 14-item questionnaire about primary immunodeficiency was applied to physicians who worked at general hospitals. One of the questions presented 25 clinical situations that could be associated or not with primary immunodeficiency, and the percentage of appropriate answers generated a knowledge indicator.

RESULTS

Seven hundred and forty-six participated in the study, among them 215 pediatricians (28.8%), 244 surgeons (32.7%), and 287 clinicians (38.5%). About 70% of the physicians responded that they had learned about primary immunodeficiency in graduate school or in residency training. Treatment of patients that use antibiotics frequently was reported by 75% dos physicians, but only 34.1% had already investigated a patient and 77.8% said they did not know the ten warning signs for primary immunodeficiency. The knowledge indicator obtained showed a mean of 45.72% (±17.87). Only 26.6% if the pediatricians and 6.6% of clinicians and surgeons showed a knowledge indicator of at least 67% (equivalent to an appropriate answer in two thirds of the clinical situations).

CONCLUSION

There is a deficit in medical knowledge of primary immunodeficiency in the city of São Paulo, even among pediatricians, despite having greater contact with the theme over the last few years. The improvement of information on primary immunodeficiency in the medical community is an important step towards the diagnosis and treatment process of these diseases.

A cost-effectiveness study of intravenous immunoglobulin in childhood idiopathic thrombocytopenia purpura patients with life-threatening bleeding

BACKGROUND

Although the international guideline recommends intravenous immunoglobulin (IVIG) as the first-line treatment for childhood idiopathic thrombocytopenia purpura (ITP) with life-threatening bleeding, ITP patients may not be able to access IVIG because of the limitation in health benefit packages especially in developing countries. There remains an important policy question as to whether IVIG used as a first-line treatment is worth the money spent. Thus, the objective of this study was to perform a cost-effectiveness analysis of adding IVIG to the standard treatment of platelet transfusion and corticosteroids, for the treatment of childhood ITP with life-threatening bleeding in the context of Thailand.

METHODS

A cost-effectiveness analysis using a hybrid model consisting of a decision tree and Markov models was conducted with a societal perspective. The effectiveness and utility parameters were determined by systematic reviews, while costs and mortality parameters were determined using a retrospective electronic hospital database analysis. All costs were presented in 2012 US$. The discount rate of 3 % was applied for both costs and outcomes. One-way and probabilistic sensitivity analyses were also performed.

RESULTS

The incremental cost-effectiveness ratio (ICER) was $3,172 per quality-adjusted life-year gained ($/QALY) for the addition of IVIG versus standard treatment alone. The probability of response to corticosteroids was the most influential parameter on ICER. According to the willingness-to-pay of Thailand, of approximately $3,861/QALY, the probability of IVIG being cost effective was 33 %.

CONCLUSIONS

The addition of IVIG to standard treatment in the treatment of childhood ITP with life-threatening bleeding is possibly a cost-effective intervention in Thailand. However, our findings were highly sensitive. Policy makers may consider our findings as part of the information for their decision making.

Guidelines for the use of human immunoglobulin therapy in patients with primary immunodeficiencies in Latin America

Antibodies are an essential component of the adaptative immune response and hold long-term memory of the immunological experiences throughout life. Antibody defects represent approximately half of the well-known primary immunodeficiencies requiring immunoglobulin replacement therapy. In this article, the authors review the current indications and therapeutic protocols in the Latin American environment. Immunoglobulin replacement therapy has been a safe procedure that induces dramatic positive changes in the clinical outcome of patients who carry antibody defects.

First report of the Hyper-IgM syndrome Registry of the Latin American Society for Immunodeficiencies: novel mutations, unique infections, and outcomes

Hyper-IgM (HIGM) syndrome is a heterogeneous group of disorders characterized by normal or elevated serum IgM levels associated with absent or decreased IgG, IgA and IgE. Here we summarize data from the HIGM syndrome Registry of the Latin American Society for Immunodeficiencies (LASID). Of the 58 patients from 51 families reported to the registry with the clinical phenotype of HIGM syndrome, molecular defects were identified in 37 patients thus far. We retrospectively analyzed the clinical, immunological and molecular data from these 37 patients. CD40 ligand (CD40L) deficiency was found in 35 patients from 25 families and activation-induced cytidine deaminase (AID) deficiency in 2 unrelated patients. Five previously unreported mutations were identified in the CD40L gene (CD40LG). Respiratory tract infections, mainly pneumonia, were the most frequent clinical manifestation. Previously undescribed fungal and opportunistic infections were observed in CD40L-deficient patients but not in the two patients with AID deficiency. These include the first cases of pneumonia caused by Mycoplasma pneumoniae, Serratia marcescens or Aspergillus sp. and diarrhea caused by Microsporidium sp. or Isospora belli. Except for four CD40L-deficient patients who died from complications of presumptive central nervous system infections or sepsis, all patients reported in this study are alive. Four CD40L-deficient patients underwent successful bone marrow transplantation. This report characterizes the clinical and genetic spectrum of HIGM syndrome in Latin America and expands the understanding of the genotype and phenotype of this syndrome in tropical areas.

Advancing the management of primary immunodeficiency diseases in Latin America: Latin American Society for Immunodeficiencies (LASID) Initiatives

Primary immunodeficiency diseases (PIDD) are associated with significant morbidity and mortality and result in a significant public health burden. This is in part due to the lack of appropriate diagnosis and treatment of these patients. It is critical that governments become aware of this problem and provide necessary resources to reduce this impact on health care systems. Leading physicians in their respective countries must be supported by their own governments in order to implement tools and provide education and thus improve the diagnosis and treatment of PIDD. The Latin American Society of Primary Immunodeficiencies (LASID) has initiated a large number of activities aimed at achieving these goals, including the establishment of a PIDD registry, development of educational programmes and guidelines, and the introduction of a PIDD fellowship programme. These initiatives are positively impacting the identification and appropriate treatment of patients with PIDD in Latin America. Nevertheless, much remains to be done to ensure that every person with PIDD receives proper therapy.

Advances in primary immunodeficiency diseases in Latin America: epidemiology, research, and perspectives

Primary immunodeficiencies (PIDs) are genetic disorders of the immune system comprising many different phenotypes. Although previously considered rare, recent advances in their clinical, epidemiological, and molecular definitions are revealing how much we still need to learn about them. For example, geographical and ethnic variations as well as the impact of certain practices influence their frequency and presentation, making it necessary to consider their study in terms of regions. The Latin American Society for Immunodeficiencies was established as an organization dedicated to provide scientific support for basic and clinical research and to develop tools and educational resources to promote awareness in the medical community. Initiatives such as these are positively influencing the way PIDs are tackled in these countries, as shown by recent reports and publications. This paper provides a historical compilation and a current view of the many issues faced by scientists studying these diseases in these countries, highlighting the diverse scientific contributions and offering a promising perspective for the further developments in this field in Latin America.

Primary immunodeficiencies in highly consanguineous North African populations

The study of inbred populations has contributed remarkably to the description of new autosomal recessive primary immunodeficiencies (PIDs). Here, we examine the pattern of PIDs in North African populations and assess the impact of highly prevalent consanguinity. This review reports on the current status of pediatricians' awareness of PIDs in Egypt, Morocco, and Tunisia, where awareness of PIDs is relatively recent. The phenotypic distribution of PIDs is reported and compared among the three countries and with other populations. Data analysis reveals a prevalence of autosomal recessive forms and a peculiar distribution of major PID categories, particularly more combined immunodeficiencies than antibody disorders. In these endogamous communities, molecular diagnosis is critical to developing a genetic-based preventive approach. The organization of diagnosis and care services in these resource-limited settings faces many obstacles. Autosomal recessive PIDs are overrepresented; thus, it is critical to continue investigation of these diseases in order to better understand the underlying mechanisms and to improve patient care.