IgA nephropathy in a child with X-linked agammaglobulinemia: a case report.

BACKGROUND: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations in the Bruton tyrosine kinase (BTK) gene. Individuals diagnosed with XLA are at an increased risk of developing autoimmune diseases. However, renal involvement are rare in cases of XLA. CASE PRESENTATION: In this report, we discussed a specific case involving a 6-year-old boy with XLA who experienced recurrent upper respiratory tract infections since the age of one. He presented with symptoms of hematuria and proteinuria, and renal pathology confirmed the presence of immunoglobulin (Ig) A nephropathy. Treatment comprised glucocorticoids, mycophenolate mofetil, and intermittent intravenous immunoglobulin replacement therapy. Consequently, there was a remission of proteinuria and a partial improvement in hematuria. CONCLUSIONS: In this study, we describe the first case of IgA nephropathy associated with XLA. This is an interesting phenotype found in XLA, and it provides valuable insights into the process of autoimmunity and the regulation of immune function in individuals with XLA. Based on our findings, we recommend the evaluation of immunoglobulin levels in patients diagnosed with IgA nephropathy.

Case report: Rapidly progressive neurocognitive disorder with a fatal outcome in a patient with PU.1 mutated agammaglobulinemia.

Introduction: PU.1-mutated agammaglobulinemia (PU.MA) represents a recently described autosomal-dominant form of agammaglobulinemia caused by mutation of the SPI1 gene. This gene codes for PU.1 pioneer transcription factor important for the maturation of monocytes, B lymphocytes, and conventional dendritic cells. Only six cases with PU.MA, presenting with chronic sinopulmonary and systemic enteroviral infections, have been previously described. Accumulating literature evidence suggests a possible relationship between SPI1 mutation, microglial phagocytic dysfunction, and the development of Alzheimer's disease (AD). Case description: We present a Caucasian female patient born from a non-consanguineous marriage, who was diagnosed with agammaglobulinemia at the age of 15 years when the immunoglobulin replacement therapy was started. During the following seventeen years, she was treated for recurrent respiratory and intestinal infections. At the age of 33 years, the diagnosis of celiac-like disease was established. Five years later progressive cognitive deterioration, unstable gait, speech disturbances, and behavioral changes developed. Comprehensive microbiological investigations were negative, excluding possible infective etiology. Brain MRI, 18FDG-PET-CT, and neuropsychological testing were suggestive for a diagnosis of a frontal variant of AD. Clinical exome sequencing revealed the presence of a novel frameshift heterozygous variant c.441dup in exon 4 of the SPI1 gene. Despite intensive therapy, the patient passed away a few months after the onset of the first neurological symptoms. Conclusion: We describe the first case of PU.MA patient presenting with a rapidly progressive neurocognitive deterioration. The possible role of microglial dysfunction in patients with SPI1 mutation could explain their susceptibility to neurodegenerative diseases thus highlighting the importance of genetic testing in patients with inborn errors of immunity. Since PU.MA represents a newly described form of agammaglobulinemia, our case expands the spectrum of manifestations associated with SPI1 mutation.

Secondary hypogammaglobulinemia in adults—A large retrospective cohort study / Hipogammaglobulinemia secundaria en adultos: estudio de cohorte retrospectiva

Background and objective: IgG replacement therapy (IgG-RT) has radically changed the clinical evolution of primary immunodeficiencies, yet the information regarding secondary hypogammaglobulinemia (SHG) is insufficient or conflicting. We aim to describe clinical features, evolution and treatment of SHG patients in our center. Methods: Dynamic retrospective cohort between January 2001 and July 2021 of adults with gamma globulin fraction <0.6g/dL in a serum protein electrophoresis and a coincident decrease of IgG levels – with a disease-related SHG or treatment that reduces serum immunoglobulins. Results: We included 1012 patients with SHG with a median follow-up of 5 years (IQR 2–8). Hematological diseases were identified in 95% of the patients and 61% received drugs related to SHG. Sixty five percent had more than one etiological factor associated with SHG. Infectious diseases were present in 69% of the patients, 48% had respiratory infections and 17% had severe infections. There was statistical association between respiratory and severe infections with multiple myeloma (MM), lymphoma and rituximab. MGUS had less infections and death compared with other etiologies. IgG-RT was indicated in 18.7% of the patients and 4.6% received it for more than 6 months with variable intervals. Among the latter group, there was a significant reduction of all-type infections and respiratory infections with IgG-RT (p<0.001), and it was consistent with similar findings in lymphoma, MM and all IgG levels subgroups. Conclusion: SHG was associated with more than one etiological factor and a high frequency of infections. IgG-RT indication was irregular yet still effective. It is relevant to consider IgG levels screening, monitoring and accurate indication of IgG-RT.(AU)

Antecedentes y objetivos: La IgG sustitutiva ha cambiado radicalmente la evolución de las inmunodeficiencias primarias, mientras que la información sobre hipogammaglobulinemia secundaria (HGS) es insuficiente y discordante. El objetivo del estudio es describir las características clínicas, evolución y tratamiento de pacientes con HGS. Métodos: Cohorte retrospectiva dinámica entre enero de 2001 y julio de 2021 de adultos con proteinograma y fracción de gammaglobulina <0,6g/dL y dosaje disminuido de IgG, con enfermedad o tratamiento que produzcan HGS. Resultados: Se incluyó a 1.012 pacientes con HGS con una mediana de seguimiento de 5 años (IIC 2-8). El 95% tenía enfermedad hematológica y el 61% recibió fármacos asociados a HGS. El 65% tenía más de un factor etiológico asociado con HGS. El 69% presentó infecciones de cualquier tipo, el 48% infecciones respiratorias y el 17%, infecciones graves. Hubo asociación significativa entre infecciones respiratorias y graves entre los subgrupos de mieloma múltiple, linfoma y rituximab. Los pacientes con MGUS tuvieron menor frecuencia de infecciones y muerte comparados con otros factores etiológicos. El 18,7% de los pacientes recibió IgG sustitutiva y el 4,6% de forma crónica, con intervalos variables. Los últimos tuvieron disminución significativa de infecciones de cualquier tipo e infecciones respiratorias con IgG sustitutiva (p<0,001), que se mantuvo en los subgrupos con mieloma múltiple, linfoma y todos los niveles de IgG. Conclusión: La HGS asoció más de un factor etiológico y alta frecuencia de infecciones. La indicación de IgG sustitutiva fue irregular, pero, aún así, efectiva. Se plantea considerar el dosaje de inmunoglobulinas, monitoreo y la adecuada indicación de IgG sustitutiva.(AU)

X-Linked Lymphoproliferative Syndrome: A Spectrum of Clinical and Immunological Profile and Novel Pathogenic Variants from Chandigarh, India.

INTRODUCTION: X-linked lymphoproliferative syndrome (XLP) is a rare primary immune deficiency. Two types of XLP have been described: XLP-1 and XLP-2. METHODS: We found 7 patients with XLP (3 had XLP-1 and 4 had XLP-2) after reviewing the data from Pediatric Immunodeficiency Clinic from 1997 to 2021. RESULTS: Mean age at diagnosis was 3.8 years, and mean delay in diagnosis was 2.6 years. Five patients had recurrent episodes of infections. Four patients developed at least one episode of hemophagocytic lymphohistiocytosis (HLH) (2 with XLP-1 and 2 with XLP-2). Of these, 2 had recurrent HLH (both with XLP-2). Epstein-Barr virus (EBV) infection was detected in 2 (1 with XLP-1 and 1 with XLP-2). Both these patients had HLH. One child with XLP-2 had inflammatory bowel disease. Hypogammaglobulinemia was seen in 3 (2 with XLP-1 and 1 with XLP-2). Genetic analysis showed previously reported variants in 5, while 2 had novel variants (one in exon 7 of XIAP gene [c.1370dup p.Asn457Lysfs Ter16] and other had splice site variant in intron 1 of SH2D1A gene [c.138-2_138-1insG]). Episodes of HLH were managed with intravenous immunoglobulin (IVIg), methylprednisolone, oral prednisolone, cyclosporine, and rituximab. Inflammatory bowel disease was managed using oral prednisolone and azathioprine. One patient underwent haploidentical hematopoietic stem cell transplantation. One child with XLP-2 and WAS died because of fulminant pneumonia. DISCUSSION/CONCLUSIONS: XLP should be considered as a strong possibility in any patient with features of HLH, repeated infections with hypogammaglobulinemia, persistent EBV infection, and early-onset IBD.

Prediction of severe infections in chronic lymphocytic leukemia: a simple risk score to stratify patients at diagnosis.

Chronic Lymphocytic Leukemia (CLL) is well-known for increasing susceptibility to infections. Factors such as immune dysregulation, IGHV status, hypogammaglobulinemia, and patient comorbidity and treatment, contribute to higher infection rates and mortality. However, the impact of hypogammaglobulinemia on infection rates is controversial. We aimed to identify clinical and biological parameters linked to the risk of severe infectious events. Additionally, we set up a straightforward risk infection score to stratify CLL patients at diagnosis, thereby enabling the development of suitable infection prevention strategies. We retrospectively evaluated 210 unselected CLL patients diagnosed between 1988 and 2018. This evaluation encompassed demographics, Binet stage, immunoglobulin (Ig) levels, treatment history, comorbidities, and IGHV mutational status at diagnosis. The frequency and severity of infectious events were recorded. Analysis revealed that age, IGHV mutational status, Binet stage, and hypogammaglobulinemia were statistically associated with the Time to First Infection (TTFI) in univariate and multivariate analyses. Using hazard ratios from the multivariate analysis, we finally devised a risk scoring system that integrated age, IGHV mutational status, immunoglobulin levels, and Binet stage to stratify patients at diagnosis based on their specific infection risk. In our cohort, disease progression and infections were the leading cause of death. These findings pointed out the clinical need for a screening process strategic for defining infectious risk at the time of CLL diagnosis, with a significant enhancement in the clinical management of these patients.

Good syndrome and cytomegalovirus retinitis: A literature review.

Good syndrome (GS) is a rare primary immunodeficiency in adults consisting of hypogammaglobulinemia and thymoma that affects both cellular and humoral immunity. It usually appears in patients between the 4th and 6th decade of life and affects both genders equally. Ophthalmological clinical presentation is highly variable; associations with herpetic keratitis, toxoplasmosis, and cytomegalovirus retinitis (CMVR) have been described. GS associated with CMVR is uncommon. Ophthalmologists may be the first to diagnose systemic disease and change the outcome. Only18 cases of CMVR have been described, most of them unilateral with poor visual outcomes. We discuss the clinical features of CMVR in patients with reported GS, pathogenesis, and outline a work-up for diagnosis. CMVR in an apparently healthy patient should encourage the clinician to search for human immunodeficiency virus (HIV) and non-HIV-associated immunosuppression.

Secondary hypogammaglobulinemia in adults-A large retrospective cohort study.

BACKGROUND AND OBJECTIVE: IgG replacement therapy (IgG-RT) has radically changed the clinical evolution of primary immunodeficiencies, yet the information regarding secondary hypogammaglobulinemia (SHG) is insufficient or conflicting. We aim to describe clinical features, evolution and treatment of SHG patients in our center. METHODS: Dynamic retrospective cohort between January 2001 and July 2021 of adults with gamma globulin fraction <0.6g/dL in a serum protein electrophoresis and a coincident decrease of IgG levels - with a disease-related SHG or treatment that reduces serum immunoglobulins. RESULTS: We included 1012 patients with SHG with a median follow-up of 5 years (IQR 2-8). Hematological diseases were identified in 95% of the patients and 61% received drugs related to SHG. Sixty five percent had more than one etiological factor associated with SHG. Infectious diseases were present in 69% of the patients, 48% had respiratory infections and 17% had severe infections. There was statistical association between respiratory and severe infections with multiple myeloma (MM), lymphoma and rituximab. MGUS had less infections and death compared with other etiologies. IgG-RT was indicated in 18.7% of the patients and 4.6% received it for more than 6 months with variable intervals. Among the latter group, there was a significant reduction of all-type infections and respiratory infections with IgG-RT (p<0.001), and it was consistent with similar findings in lymphoma, MM and all IgG levels subgroups. CONCLUSION: SHG was associated with more than one etiological factor and a high frequency of infections. IgG-RT indication was irregular yet still effective. It is relevant to consider IgG levels screening, monitoring and accurate indication of IgG-RT.

Unraveling the Natural History of Good's Syndrome: A Progressive Adult Combined Immunodeficiency.

BACKGROUND: Good's syndrome (GS) is a rare immune deficiency described almost 6 decades ago. Despite numerous published individual case reports and data collected in cross-sectional studies of small cohorts, the natural history and long-term outcomes of this disease remain unknown. OBJECTIVE: We aimed to determine the clinical and laboratory evolution of 8 adults diagnosed with GS and consecutively evaluated between 1983 and 2023. METHODS: In this prospective, longitudinal cohort study, newly diagnosed patients with GS were followed through repeated measures of clinical, immune, and hematologic changes, as well as targeted genetic screening. RESULTS: All patients reported a healthy childhood and adolescence with symptom onset during the third or fourth decade of life. All presented to our center with recurrent bacterial sinopulmonary infections, thymoma, hypogammaglobulinemia, and absence of B cells. The median age of GS diagnosis was 57 years. During follow-up, immunoglobin replacement therapy effectively minimized sinopulmonary infections. However, the majority experienced severe and systemic viral or fungal infections, 3 developed basal cell carcinomas, and 5 had progressive bronchiectasis and persistent splenomegaly. The most notable clinical feature was opportunistic infections and in vitro evidence of cellular immune deficiency, which resulted in the death of 2 individuals. We also report a statistically significant, multidecade progressive decline in lymphocytes, platelets, hemoglobin, and red blood cells in our cohort, suggesting gradual bone marrow failure. CONCLUSIONS: Knowledge of the unique phenotype and temporal evolution of GS has allowed us to develop a more comprehensive diagnostic framework. It can be investigated as part of broader research into disease pathophysiology.

Combined Treatment of Progressive Encephalitis in an X-linked Agammaglobulinemia Patient.

Most patients with X-linked agammaglobulinemia are susceptible to infections, while some cases also suffer from inflammatory or autoimmune complications. We describe a patient with progressive encephalitis who improved after the use of immunomodulatory treatment with corticosteroids, fluoxetine, and nitazoxanide. In most of the cases the evolution of the progressive encephalitis is complicated and catastrophic. Based on our experience and the review of the literature, we propose the use of this combined treatment to control this devastating complication.

In-depth blood immune profiling of Good syndrome patients.

Introduction: Good syndrome (GS) is a rare adult-onset immunodeficiency first described in 1954. It is characterized by the coexistence of a thymoma and hypogammaglobulinemia, associated with an increased susceptibility to infections and autoimmunity. The classification and management of GS has been long hampered by the lack of data about the underlying immune alterations, a controversy existing on whether it is a unique diagnostic entity vs. a subtype of Common Variable Immune Deficiency (CVID). Methods: Here, we used high-sensitive flow cytometry to investigate the distribution of up to 70 different immune cell populations in blood of GS patients (n=9) compared to age-matched CVID patients (n=55) and healthy donors (n=61). Results: All 9 GS patients displayed reduced B-cell counts -down to undetectable levels (<0.1 cells/µL) in 8/9 cases-, together with decreased numbers of total CD4+ T-cells, NK-cells, neutrophils, and basophils vs. age-matched healthy donors. In contrast, they showed expanded TCRγδ+ T-cells (p ≤ 0.05). Except for a deeper B-cell defect, the pattern of immune cell alteration in blood was similar in GS and (age-matched) CVID patients. In depth analysis of CD4+ T-cells revealed significantly decreased blood counts of naïve, central memory (CM) and transitional memory (TM) TCD4+ cells and their functional compartments of T follicular helper (TFH), regulatory T cells (Tregs), T helper (Th)2, Th17, Th22, Th1/Th17 and Th1/Th2 cells. In addition, GS patients also showed decreased NK-cell, neutrophil, basophil, classical monocyte and of both CD1c+ and CD141+ myeloid dendritic cell counts in blood, in parallel to an expansion of total and terminal effector TCRγδ+ T-cells. Interestingly, those GS patients who developed hypogammaglobulinemia several years after the thymoma presented with an immunological and clinical phenotype which more closely resembled a combined immune humoral and cellular defect, with poorer response to immunoglobulin replacement therapy, as compared to those in whom the thymoma and hypogammaglobulinemia were simultaneously detected. Discussion: Our findings provide a more accurate definition of the immune cell defects of GS patients and contribute to a better discrimination among GS patients between those with a pure B-cell defect vs. those suffering from a combined immunodeficiency with important consequences on the diagnosis and management of the disease.

Transcriptome profiling of regulatory T cells from children with transient hypogammaglobulinemia of infancy.

Transient hypogammaglobulinemia of infancy (THI) is one of the most common forms of hypogammaglobulinemia in the early childhood. THI is usually associated with chronic, recurrent bacterial and viral infections, life-threatening in some cases, yet its pathogenesis is still largely unknown. As our previous findings indicated the possible role of Treg cells in the pathomechanism of THI, the aim of the current study was to investigate gene expression profile of Treg cells isolated from THI patients. The transcriptome-wide gene profiling was performed using microarray technology on THI patients in two time-points: during (THI-1), and in resolution phase (THI-2) of hypogammaglobulinemia. As a result, a total of 1086 genes were differentially expressed in THI-1 patients, when compared to THI-2 as well as control group. Among them, 931 were up- and 155 downregulated, and part of them encodes genes important for Treg lymphocyte biology and function, i.e. transcription factors/cofactors that regulate FOXP3 expression. Thus, we postulate that Treg cells isolated from THI patients during hypogammaglobulinemia display enhanced suppressor transcriptome signature. Treg expression profile of THI children after normalization of Ig levels largely resembles the results obtained in healthy control group, suggesting THI Treg transcriptome seems to return to that observed in healthy children. Taken together, we suggest that THI pathomechanism is associated not only with transiently elevated Treg cell numbers, but also with their enhanced regulatory/inhibitory functions. These findings expand our knowledge of human Treg cells and may be useful for the future diagnosis or management of THI.

Hypogammaglobulinemia, a new risk factor for hepatitis B virus reactivation : about two cases.

Reactivation of the hepatitis B virus (HBV) with immunosuppressive status has been well established, mainly due to medications such as immunosuppressive therapy like cytotoxic chemotherapy, rituximab and biologic therapy, immunosuppression after solid and bone-marrow transplantation or long-term corticosteroids therapy. We report here two cases of HBV reactivation due to global hypogammaglobulinemia. Regular HBV serologic screening and PCR for HBV-DNA should be applied for each patient with primary immunosuppressive status and history of chronic HBV infection. The necessity of a preemptive treatment remains debated.

Investigation of a synonymous mutation in Btk in a patient with agammaglobulinemia: A case report.

BACKGROUND: X-linked agammaglobulinemia (XLA) is the most common form of agammaglobulinemia and is caused by mutations in Btk, which encodes Bruton tyrosine kinase (BTK). CASE DESCRIPTION: We describe a 36-year-old male who presented as an infant with hypogammaglobulinemia and sinopulmonary infections and was initially diagnosed with common variable immunodeficiency. Genetic testing showed he was hemizygous for Btk c.240G > A. This synonymous variant affecting the last nucleotide of exon 3 leads to aberrant splicing of most but not all mRNA transcripts. CONCLUSION: We demonstrated reduced BTK protein expression confirming the pathogenicity of the variant and related our findings to genotype-phenotype relationship studies ina XLA caused by synonymous mutations.

Clinical features and mutational analysis of X-linked agammaglobulinemia patients in Malaysia.

Background: Bruton's tyrosine kinase (BTK) is a cytoplasmic protein involved in the B cell development. X-linked agammaglobulinemia (XLA) is caused by mutation in the BTK gene, which results in very low or absent B cells. Affected males have markedly reduced immunoglobulin levels, which render them susceptible to recurrent and severe bacterial infections. Methods: Patients suspected with X-linked agammaglobulinemia were enrolled during the period of 2010-2018. Clinical summary, and immunological profiles of these patients were recorded. Peripheral blood samples were collected for monocyte BTK protein expression detection and BTK genetic analysis. The medical records between January 2020 and June 2023 were reviewed to investigate COVID-19 in XLA. Results: Twenty-two patients (from 16 unrelated families) were molecularly diagnosed as XLA. Genetic testing revealed fifteen distinct mutations, including four splicing mutations, four missense mutations, three nonsense mutations, three short deletions, and one large indel mutation. These mutations scattered throughout the BTK gene and mostly affected the kinase domain. All mutations including five novel mutations were predicted to be pathogenic or deleterious by in silico prediction tools. Genetic testing confirmed that eleven mothers and seven sisters were carriers for the disease, while three mutations were de novo. Flow cytometric analysis showed that thirteen patients had minimal BTK expression (0-15%) while eight patients had reduced BTK expression (16-64%). One patient was not tested for monocyte BTK expression due to insufficient sample. Pneumonia (n=13) was the most common manifestation, while Pseudomonas aeruginosa was the most frequently isolated pathogen from the patients (n=4). Mild or asymptomatic COVID-19 was reported in four patients. Conclusion: This report provides the first overview of demographic, clinical, immunological and genetic data of XLA in Malaysia. The combination of flow cytometric assessment and BTK genetic analysis provides a definitive diagnosis for XLA patients, especially with atypical clinical presentation. In addition, it may also allow carrier detection and assist in genetic counselling and prenatal diagnosis.

Antibody Deficiency in Patients with Biallelic KARS1 Mutations.

Biallelic KARS1 mutations cause KARS-related diseases, a rare syndromic condition encompassing central and peripheral nervous system impairment, heart and liver disease, and deafness. KARS1 encodes the t-RNA synthase of lysine, an aminoacyl-tRNA synthetase, involved in different physiological mechanisms (such as angiogenesis, post-translational modifications, translation initiation, autophagy and mitochondrial function). Although patients with immune-hematological abnormalities have been individually described, results have not been collectively discussed and functional studies investigating how KARS1 mutations affect B cells have not been performed. Here, we describe one patient with severe developmental delay, sensoneurinal deafness, acute disseminated encephalomyelitis, hypogammaglobulinemia and recurrent infections. Pathogenic biallelic KARS1 variants (Phe291Val/ Pro499Leu) were associated with impaired B cell metabolism (decreased mitochondrial numbers and activity). All published cases of KARS-related diseases were identified. The corresponding authors and researchers involved in the diagnosis of inborn errors of immunity or genetic syndromes were contacted to obtain up-to-date clinical and immunological information. Seventeen patients with KARS-related diseases were identified. Recurrent/severe infections (9/17) and B cell abnormalities (either B cell lymphopenia [3/9], hypogammaglobulinemia [either IgG, IgA or IgM; 6/15] or impaired vaccine responses [4/7]) were frequently reported. Immunoglobulin replacement therapy was given in five patients. Full immunological assessment is warranted in these patients, who may require detailed investigation and specific supportive treatment.

[Early detection of WHIM symdrome. A case report]. / Identificación temprana de síndrome de WHIM. Informe de un caso.

BACKGROUND: WHIM syndrome corresponds to an inborn error of innate and intrinsic immunity, characterized by: warts (Warts), Hypogammaglobulinemia, Infections and Myelocathexis, for its acronym in English. CASE REPORT: 4-year-old male, with severe neutropenia and B-cell lymphopenia from birth, without severe infections or warts; the panel genetic sequencing study of primary immunodeficiencies with the CXCR4 c.1000C>T (p.Arg334*) variant, which is associated with WHIM syndrome. CONCLUSIONS: The diagnosis of severe neutropenia from birth should include the search for inborn errors of immunity, through genetic sequencing studies, especially in asymptomatic or oligosymptomatic patients.

ANTECEDENTES: El síndrome WHIM corresponde a un error innato de la inmunidad innata e intrínseca, caracterizada por verrugas (Warts), hipogammaglobulinemia, infecciones y mielocatexis, por sus siglas en inglés. REPORTE DE CASO: Paciente masculino de 4 años, con neutropenia severa y linfopenia de células B desde el nacimiento, sin infecciones severas ni verrugas. El estudio de secuenciación genética informó la variante CXCR4 c.1000C>T (p.Arg334*), relacionada con el síndrome de WHIM. CONCLUSIÓN: El diagnóstico de neutropenia severa desde el nacimiento debe incluir la búsqueda de errores innatos de la inmunidad, mediante estudios de secuenciación genética, especialmente en pacientes asintomáticos u oligosintomáticos.