Nova mutação no gene STAT1 associada com candidíase mucocutânea crônica / New STAT1 gene mutation associated with chronic mucocutaneous candidiasis

Mutações no gene STAT1 (signal transducer and activator of transcription 1) têm sido identificadas como responsáveis pela maioria dos casos sindrômicos da candidíase mucocutânea crônica com herança autossômica dominante (AD). Nesse artigo, descrevemos uma menina de 7 anos que apresentou candidíase da mucosa oral e unhas, além de infecção disseminada da pele e couro cabeludo por Microspora gipseum. Recentemente, a paciente foi diagnosticada e tratada de meningite por Cryptococcus neoformans. Na família não existem outros casos de candidíase. A avaliação imunológica incluiu a detecção de subpopulações de linfócitos (CD3, CD4, CD8, CD20 e células NK), assim como a dosagem de IgG, IgA, IgM e IgE, subclasses de IgG e autoanticorpos. Excluindo-se discreta diminuição de CD3, CD4, CD8, NK e leve aumento de IgG1, os demais exames estiveram dentro da normalidade. O sequenciamento do exoma detectou uma rara mutação em heterozigose no exon 14 do domínio de ligação do DNA (DNA-binding domain) do gene STAT1, ocasionando um provável ganho de função (GOF) responsável pela doença (Gly384Asp). Essa variação foi também identificada pelo sequenciamento de Sanger, não estando reportada nos bancos de dados públicos e apresentando elevado potencial de dano (índice CADD=32). Será interessante contarmos com informações clínicas e estudos com outros pacientes para conhecermos mais essa mutação patológica. Além da apresentação do caso, discutiremos as formas de tratamento existentes.

STAT1 (signal transducer and activator of transcription 1) gene mutations have been identified as responsible for most syndromic cases of chronic mucocutaneous candidiasis with autosomal dominant (AD) inheritance. In this article, we described a 7-year-old girl who presented with candidiasis of the oral mucosa and nails, as well as disseminated infection of the skin and scalp caused by Microsporum gypseum. Recently, the patient was diagnosed and treated for Cryptococcus neoformans meningitis. There are no other cases of candidiasis in the family. The immunological evaluation consisted of detection of subpopulations of lymphocytes (CD3, CD4, CD8, CD20, and NK cells), as well as measurement of IgG, IgA, IgM, and IgE, IgG subclasses, and autoantibodies. Excluding a slight decrease in CD3, CD4, CD8, NK and a minimal increase in IgG1, the others were within normal limits. Exome sequencing detected a rare heterozygous variation in exon 14 of the DNA-binding domain of the STAT1 gene, causing a probable gain of function (GOF) responsible for the disease (Gly384Asp). This variation was also identified by Sanger sequencing, but it was not reported in public databases and had a high potential for damage (Combined Annotation-Dependent Depletion [CADD] score = 32). Having clinical information and conducting studies of other patients will be helpful to learn more about this pathological mutation. In addition to the presentation of the case, we will discuss the existing forms of treatment.

Infecção por SARS-CoV-2 em paciente com agamaglobulinemia ligada ao X tratado com altas doses de imunoglobulina endovenosa e plasma de convalescente / SARS-CoV-2 infection in a patient with X-linked agammaglobulinemia treated with high doses of intravenous immunoglobulin and convalescent plasma

A pandemia pelo vírus SARS-CoV-2 atingiu adultos, crianças e penalizou indivíduos idosos e com comorbidades como diabetes, doença cardíaca, hipertensão e obesidade. A maioria dos infectados são assintomáticos ou têm sintomas leves, entretanto 15% podem apresentar pneumonia e 5% síndrome respiratória aguda grave. Apresentamos um caso de agamaglobulinemia ligada ao X (XLA) em paciente masculino de 27 anos que se infectou com SARS-CoV-2. Os pacientes com XLA não possuem linfócitos B e não produzem anticorpos devido a uma mutação no gene Bruton tirosino-quinase (BTK), responsável pela maturação dos linfócitos B. Ele infectou-se e foi internado em hospital de Ivoti/RS. A evolução da pneumonia foi rápida, necessitando transferência para o Hospital de Clínicas de Porto Alegre (HCPA) no 10° dia de evolução. Iniciou com infusão de imunoglobulinas, tendo utilizado o total de 400 gramas devido ao intenso catabolismo da IgG, mantendo-se sua concentração entre 700-900 mg/dL. Necessitou de ventilação mecânica, oxigenação por membrana extracorpórea (ECMO) e hemodiálise. Foi administrado plasma de convalescente (PC), 300 mL, por duas vezes, com melhora clínico-radiológica e retirada da ventilação mecânica. Piorou e repetiu outras 4 infusões de PC (total de 1717 mL), negativando o vírus na orofaringe (RT-PCR). Em 3 ocasiões teve sepse, debelada rapidamente. Apresentou anemia, com necessidade de transfusão frequente. Identificou-se linfopenia de CD3, CD4, CD8, NK e ausência de linfócitos B. A linfopenia foi revertida com a recuperação clínica e a alta hospitalar aconteceu no 70° dia de internação.

The SARS-CoV-2 pandemic has affected adults and children and penalized older people and those with comorbidities such as diabetes, heart disease, hypertension and obesity. Most of those infected are asymptomatic or have mild symptoms, but 15% may have pneumonia and 5% acute respiratory distress syndrome. We report a case of X-linked agammaglobulinemia (XLA) in a 27-yearold man who was infected with SARS-CoV-2. XLA patients do not have B lymphocytes and do not produce antibodies because of mutations in the Bruton tyrosine-kinase gene, responsible for the maturation of B cells. This patient was infected and then admitted to a hospital in Ivoti, southern Brazil. Pneumonia progressed rapidly, requiring transfer to the Hospital de Clínicas de Porto Alegre on the 10th day. Intravenous immunoglobulin infusions were initiated, using a total of 400 grams because of an intense catabolism of IgG, and the concentration was kept around 700- 900 mg/dL. Mechanical ventilation, extracorporeal membrane oxygenation and hemodialysis were necessary. Convalescent plasma (CP) was administered (2x300 mL) and then followed by clinical and radiological improvement and interruption of mechanical ventilation. Then he got sicker and had to return to invasive support and received 4 extra CP infusions (total of 1717 mL), until a negative reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2 was obtained. On 3 occasions he had sepsis, promptly managed. He had anemia, requiring frequent transfusion, and lymphopenia (CD3, CD4, CD8, NK), with absence of B lymphocytes. Lymphopenia was reverted during recovery, and he was discharged from the hospital on the 70th day.

Comparative analysis of two methods to detect donor-specific anti-HLA antibodies after kidney transplant.

Preformed anti-human leukocyte antigen (HLA) antibodies may be present in the blood of kidney transplant candidates. The production of these antibodies may occur in the post-transplant period, with the possible development of donor-specific antibodies (DSA). Luminex-based tests, such as the single antigen (SA) assay and the Luminex crossmatch (Xm-DSA) assay are the most commonly used tools to detect anti-HLA antibodies, due to their high sensitivity and specificity. This cross-sectional study aimed to compare the findings of two methods for the detection of DSAs after kidney transplant: SA and Xm-DSA. A total of 122 patients who underwent deceased donor kidney transplant at Hospital de Clínicas de Porto Alegre were included. The SA assay detected anti-class I HLA DSAs in 17 patients (13.9%) and anti-class II HLA DSAs in 22 patients (19.6%), whereas the Xm-DSA detected DSAs in 18 patients (14.8%) both against class I and class II antigens. There was agreement between the two methods for class I (kappa = 0.66, p = 0.001) and class II (kappa = 0.54, p = 0.025) antigens. The incidence of DSAs as obtained by the SA assay was 15.57%, and the most prevalent DSAs were those against HLA-DR antigens. Patient survival at 3 years was 92%. The two techniques assessed in this study provide important information on the presence of DSAs and may help in the post-transplant patient monitoring and in immunosuppressive strategy.

Blood chimerism in twins.

CONCLUSIONS: Chimerism is a phenomenon in which an individual has cells with different genetic content from different zygotes. In dizygotic twins (DTs), chimerism is believed to occur through placental anastomoses that enable the bidirectional exchange of hematopoietic stem cells. Little is still known about chimerism frequency in twins, but several studies have shown a relation between chimerism and some conditions such as autism, Alzheimer's disease, and a group of autoimmune diseases such as Sjögren syndrome, systemic lupus erythematosus, and systemic sclerosis. In addition to chimerism of ABO blood groups being possibly mistaken for ABO subgroups, these autoimmune diseases may affect other serologic immunohematologic tests. This study aimed to determine the frequency of chimerism in DTs through ABO and D testing using the tube method, column agglutination, and short tandem repeat (STR) assays. Among the 103 subjects assessed for this study, 24 subjects (12 pairs) were excluded because STR assays showed they were monozygotic; of the remaining, 70 subjects (35 pairs) were DTs and 9 subjects came from gestations of trizygotic triplets. No ABO or D chimerism was detected in any subject through serologic assays, and STR assays did not detect any blood chimerism. Although there was no evidence of chimerism found in this study, we emphasize the importance of observing the family background of individuals with suspected ABO subgroup in complex immunohematologic studies because ABO antigen-antibody reactions are similar in both circumstances, and chimerism can be overlooked. Moreover, the use of the STR analysis method in chimerism studies can be important to help differentiate chimerism and ABO subgroups.

Quantification of mixed chimerism allows early therapeutic interventions.

Hematopoietic stem cell transplantation is the curative option for patients with myelodysplastic syndrome; however, it requires a long post-transplantation follow-up. A 53-year-old woman with a diagnosis of myelodysplastic syndrome underwent related donor allogeneic hematopoietic stem cell transplantation in July 2006. Three months after transplantation, a comparative short tandem repeat analysis between donor and recipient revealed full chimerism, indicating complete, healthy bone marrow reconstitution. Three years and ten months after hematopoietic stem cell transplantation, the patient developed leukopenia and thrombocytopenia. Another short tandem repeat analysis was carried out which showed mixed chimerism (52.62%), indicating relapsed disease. A donor lymphocyte infusion was administered. The purpose of donor lymphocyte infusion is to induce a graft-versus-leukemia effect; in fact, this donor's lymphocyte infusion induced full chimerism. Successive short tandem repeat analyses were performed as part of post-transplantation follow-up, and in July 2010, one such analysis again showed mixed chimerism (64.25%). Based on this finding, a second donor lymphocyte infusion was administered, but failed to eradicate the disease. In September 2011, the patient presented with relapsed disease, and a second related donor allogeneic hematopoietic stem cell transplantation was performed. Subsequent short tandem repeat analyses revealed full chimerism, indicating complete bone marrow reconstitution. We conclude that quantitative detection of mixed chimerism is an important diagnostic tool that can guide early therapeutic intervention.

Quantification of mixed chimerism allows early therapeutic interventions

Hematopoietic stem cell transplantation is the curative option for patients with myelodysplastic syndrome; however, it requires a long post-transplantation follow-up. A 53-year-old woman with a diagnosis of myelodysplastic syndrome underwent related donor allogeneic hematopoietic stem cell transplantation in July 2006. Three months after transplantation, a comparative short tandem repeat analysis between donor and recipient revealed full chimerism, indicating complete, healthy bone marrow reconstitution. Three years and ten months after hematopoietic stem cell transplantation, the patient developed leukopenia and thrombocytopenia. Another short tandem repeat analysis was carried out which showed mixed chimerism (52.62%), indicating relapsed disease. A donor lymphocyte infusion was administered. The purpose of donor lymphocyte infusion is to induce a graft-versus-leukemia effect; in fact, this donor's lymphocyte infusion induced full chimerism. Successive short tandem repeat analyses were performed as part of post-transplantation follow-up, and in July 2010, one such analysis again showed mixed chimerism (64.25%). Based on this finding, a second donor lymphocyte infusion was administered, but failed to eradicate the disease. In September 2011, the patient presented with relapsed disease, and a second related donor allogeneic hematopoietic stem cell transplantation was performed. Subsequent short tandem repeat analyses revealed full chimerism, indicating complete bone marrow reconstitution. We conclude that quantitative detection of mixed chimerism is an important diagnostic tool that can guide early therapeutic intervention...

Development of two multiplex PCR systems for the analysis of 14 X-chromosomal STR loci in a southern Brazilian population sample.

We developed two multiplex systems for the coamplification of X-chromosomal short tandem repeats (STRs). X-Multiplex 1 consisted of DXS6807, DXS6800, DXS7424, DXS101, GATA172D05 and HPRTB and X-Multiplex 2 consisted of DXS8378, DXS9898, DXS6801, DXS6809, DXS6789, DXS7133, DXS8377 and DXS7423. In addition, we present allele frequencies for these loci in a south Brazilian population comprising 124 females and 141 males and haplotype frequencies of linked markers for males. Hardy-Weinberg equilibrium (HWE) was tested in the female sample and no significant deviations were found after applying Bonferroni's correction. Linkage disequilibrium (LD) tests were performed for all pairs of loci and three significant results, out of 91 pairwise comparisons, were obtained. We did not find any evidence of linkage disequilibrium between close or linked markers. The power of discrimination in females (PD(F)) varied between 0.832 for DXS6801 and 0.987 for DXS8377. DXS6801 was the least informative marker (PIC = 0.605), while DXS8377 was the most polymorphic (PIC = 0.911), followed by DXS101 (PIC = 0.872). Genetic distances were estimated for each STR marker applying the calculation of F (ST) between our total sample and other studies from Brazil, Europe, Asia and Africa. The most distant populations were Japan, Korea, China, Ghana and Uganda.

Common variants in the lipoprotein lipase gene in Brazil: association with lipids and angiographically assessed coronary atherosclerosis.

Lipoprotein lipase is the rate-limiting enzyme in the lipolysis of plasma triglyceride-rich lipoproteins. We studied six variants (T-93G, D9N, N291S, PvuII, HindIII and S447X) in the lipoprotein lipase (LPL) gene in 309 non-diabetic patients with angiographically assessed coronary artery disease and in 197 controls in a southern Brazilian population of European descent. The HindIII H-allele was associated with lower triglycerides (p < 0.01) and higher high-density lipoprotein cholesterol (p = 0.03) levels, and the S447X mutation was associated with lower triglyceride levels (p < 0.01) in males, but not females. No other significant lipid associations were observed. Haplotypes were derived from these two sites (HindIII/S447X), and carriers of H-S and H-X haplotypes showed lower triglycerides (p < 0.01) and increased high-density lipoprotein cholesterol (p = 0.01) levels when compared to the H+S haplotype in males. In this gender, the H-X haplotype was associated with a protective effect (OR = 0.36, 95%CI = 0.13-0.97) for significant disease (> or = 60% of luminal coronary stenosis), even controlling for other classical risk factors.

Lipoprotein lipase and APOE/APOC-I/APOC-II gene cluster diversity in native Brazilian populations.

Allele and haplotype frequencies for the T-93G, Hind III, and Pvu II variants of the lipoprotein lipase gene (LPL), and Hpa I and Ava II restriction site polymorphisms (RSP) of the APOE/C-I/C-II gene cluster were determined in 143 individuals from five Brazilian Indian tribes. These results were integrated with those previously reported for APOE. Marked interethnic variability occurs in these sites. A strong linkage disequilibrium was observed between the APOE and APOC-I loci (D' = 0.81; P < 0.00001). Linkage disequilibrium between the Hind III and Pvu II RSPs of the LPL gene was also observed (D' = 1; P < 0.001), but none of these RSPs were in linkage disequilibrium with the T-93G mutation. Considering both loci, heterozygosity was estimated as 0.45, but it was lower in the Xavante and Surui populations, in accordance with the historical and biodemographical data of these Amerindians. The results reported here may have implications for understanding interpopulation differences in lipid levels and coronary heart disease prevalences.