A Prospective Observational Study of Hypogammaglobulinemia in the First Year After Lung Transplantation

A second look at secondary hypogammaglobulinemia

Hypogammaglobulinemia is defined as a reduced immunoglobulin level, which can be either primary due to inborn errors of immunity or acquired in the setting of poor antibody production or increased antibody loss. Secondary hypogammaglobulinemia (SHG) should be considered in patients with a history of immunosuppressive therapy, transplant, protein loss syndromes, certain autoimmune conditions, and malignancies, as it can be associated with increased infectious risk. Appropriate history and lab-based screening in these populations can identify SHG allowing treatment and close monitoring as appropriate. Ideally, treatment focuses on control of the underlying condition or removal of iatrogenic causes of SHG. However, in many cases, treatment of the underlying condition does not reverse SHG or immunosuppressive therapy cannot be discontinued without significant risk to the patient. For these patients, strategies for risk mitigation against infectious complications include vaccination, antibiotic prophylaxis, and immunoglobulin replacement therapy. This report aims to summarize the existing and emerging data in the evaluation and management of SHG and highlight areas that require further investigation.

If and When to Consider Prophylactic Immunoglobulin Replacement Therapy in Secondary Hypogammaglobulinemia

Secondary hypogammaglobulinemia (SHG), or decreased IgG levels due to reduced production or increased loss caused by medications or underlying conditions, can be associated with increased infection risk. Although immunoglobulin replacement therapy (IgRT) is generally accepted as a strategy to help prevent recurrent bacterial infections in SHG, controversy exists as to whether it should be initiated to prevent the first occurrence of infection. This question has been raised particularly in the setting of anti-CD20 therapy, solid organ transplant, and B-cell malignancies and their treatments once IgG levels fall below 300 to 400 mg/dL. This article reviews the evidence for and against initiating IgRT in these settings, as well as associated considerations for evaluation and monitoring. Although it is relatively clear that infection risk increases with decreasing IgG levels, the exact contribution of SHG to overall infection risk and the protective benefit of IgRT in the absence of infections remain unclear. In the absence of clear consensus, shared decision-making is often needed to determine if and when to initiate IgRT.

Overview of secondary immunodeficiency

In contrast to inborn errors of immunity (IEI), which are inherited disorders of the immune system that predispose to infections, malignancy, atopy, and immune dysregulation, secondary immunodeficiencies and immune dysregulation states (SID) are acquired impairments in immune cell function and/or regulation, and may be transient, reversible, or permanent. SIDs can derive from a variety of medical comorbidities, including protein-losing conditions, malnutrition, malignancy, certain genetic syndromes, prematurity, and chronic infections. Medications, including immunosuppressive and chemotherapeutic drugs, can have profound effects on immunity and biologic agents used in rheumatology, neurology, and hematology/oncology practice are increasingly common causes of SID. Iatrogenic factors, including surgical procedures (thymectomy, splenectomy) can also contribute to SID. A thorough case history, medication review, and laboratory evaluation are necessary to identify the primary driver and determine proper management of SID. Careful consideration should be given to whether a primary IEI could be contributing to autoimmunity, malignancy, and posttreatment complications (e.g., antibody deficiency). SID management consists of addressing the driving condition and/or removing the offending agent if feasible. If SID is suspected to be permanent, then antibiotic prophylaxis, additional immunization, and immunoglobulin replacement should be considered.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Secondary immunodeficiencies with predominant antibody deficiency: multidisciplinary perspectives of Polish experts

At present, secondary immune deficiencies have become a clinical problem, recognized in different specialties. The aim of this paper was to increase awareness and support the need for screening at-risk populations. Secondary immune deficiencies result in variety of conditions, but not all of them require immunoglobulin replacement therapy, as specific antibody response might be preserved. Moreover, the management of secondary immune deficiencies vary between countries and different medical disciplines. This literature review presents the most common causes and clinical presentation of secondary immunodeficiencies with predominant impaired antibody production. We present diagnostic guidelines for patients at-risk, with an emphasis on the role of prophylactic vaccination as a treatment and diagnostic tool. This review considers the specificity and disparities of the Polish healthcare system and ultimately, suggests that management teams should include a clinical immunologist experienced in the treatment of humoral immunodeficiencies.

Hypogammaglobulinemia following heart transplantation: Prevalence, predictors, and clinical importance

Hypogammaglobulinemia (HGG) can occur following solid organ transplantation. However, there are limited data describing the prevalence, risk factors, and clinical outcomes associated with HGG following heart transplantation. We retrospectively reviewed data of 132 patients who had undergone heart transplantation at our institution between April 2014 and December 2018. We classified patients into three groups based on the lowest serum IgG level post-transplant: normal (≥700 mg/dL), mild HGG (≥450 and <700 mg/dL), and severe HGG (<450 mg/dL). We compared clinical outcomes from the date of the lowest IgG level. Mean age was 57 (47, 64) years, and 94 (71%) patients were male. Prevalence of severe HGG was the highest (27%) at 3-6 months following heart transplantation and then decreased to 5% after 1 year. Multivariate analysis showed that older age and Caucasian race were independent risk factors for HGG. Overall survival was comparable between the groups; however, survival free of infection was 73%, 60%, and 45% at 1 year in the normal, mild HGG, and severe HGG groups, respectively (P = .013). In conclusion, there is a high prevalence of HGG in the early post-heart transplant period that decreases over time. HGG is associated with an increased incidence of infection.

Clinical use of an immune monitoring panel in liver transplant recipients: A prospective, observational study

Immunosuppressive therapy greatly contributed to making liver transplantation the standard treatment for end-stage liver diseases. However, it remains difficult to predict and measure the efficacy of pharmacological immunosuppression. Therefore, we used a panel of standardized, commonly available, biomarkers with the aim to describe their changes in the first 3 weeks after the transplant procedure and assess if they may help therapeutic drug monitoring in better tailoring the dose of the immunosuppressive drugs. We prospectively studied 72 consecutive patients from the day of liver transplant (post-operative day #0) until the post-operative day #21. Leukocytes, neutrophils, lymphocytes (CD4+, CD8+), natural killer cells, monocytes, immunoglobulins and tacrolimus serum levels were measured on peripheral blood (at day 0, 3, 7, 14, 21 after surgery). Patients who developed infections showed significantly higher CD64+ monocytes on post operative day #7. IgG levels were lower on post operative day #3 among patients who later developed infections. We also found that a sharp decrease in IgA from post operative day #0 to 3 (-226 mg/dL in the ROC curve analysis) strongly correlates with the onset of infections among HCV- patients. No specific markers of rejection emerged from the tested panel of markers. Our results show that some early changes in peripheral blood white cells and immunoglobulins may predict the onset of infections and may be useful in modulating the immunosuppressive therapy. However, a panel of commonly available, standardized biomarkers do not support in improving therapeutic drug monitoring ability to individualize immunosuppressive drugs dosing.