Modulation of granzymes mRNA expression in neural tissue of BoAHV-1 and BoAHV-5-infected cattle.

Bovine alphaherpesviruses (BoAHV)-1 and 5 are neurotropic viruses of cattle which differ in their neuropathogenic potential. BoAHV-5 is responsible for non-suppurative meningoencephalitis in calves while BoAHV-1 can occasionally cause encephalitis. Granzymes (GZMs) are serine-proteases that participate in CD8+ T cells-mediated killing of virally-infected cells upon release through perforin (PFN)-formed pores in the cell membrane. Recently, six GZMs have been identified in cattle (A, B, K, H, M and O). However, their expression in bovine tissues has not been evaluated. In this study, the mRNA expression levels of PFN and GZMs A, B, K, H and M in the nervous system of calves experimentally-inoculated with BoAHV-1 or BoAHV-5 were analyzed at the three distinct stages of the infectious cycle of alphaherpesviruses: acute infection, latency and reactivation. This is the first report describing the expression of GZMs in bovine neural tissue and the first analysis of GZM expression in the context of bovine alphaherpesviruses neuropathogenesis. The findings revealed that PFN and GZM K are upregulated during BoAHV-1 or BoAHV-5 acute infection. In contrast to BoAHV-1, during BoAHV-5 latency a significant up-regulation of PFN, GZM K and GZM H was detected. PFN and GZM A, K and H expression was also up-regulated during BoAHV-5 reactivation. Therefore, a distinct pattern of PFN and GZM expression is evident along the infectious cycle of each alphaherpesvirus and this might contribute to the differences in BoAHV-1 and BoAHV-5 neuropathogenesis.

Immune Response Gaps Linked to SARS-CoV-2 Infection: Cellular Exhaustion, Senescence, or Both?

The COVID-19 pandemic, promoted by the SARS-CoV-2 respiratory virus, has resulted in widespread global morbidity and mortality. The immune response against this pathogen has shown a thin line between protective effects and pathological reactions resulting from the massive release of cytokines and poor viral clearance. The latter is possibly caused by exhaustion, senescence, or both of TCD8+ cells and reduced activity of natural killer (NK) cells. The imbalance between innate and adaptive responses during the early stages of infection caused by SARS-CoV-2 contributes to the ineffective control of viral spread. The present study evaluated the tissue immunoexpression of the tissue biomarkers (Arginase-1, CCR4, CD3, CD4, CD8, CD20, CD57, CD68, CD138, IL-4, INF-α, INF-γ, iNOS, PD-1, Perforin and Sphingosine-1) to understand the cellular immune response triggered in patients who died of COVID-19. We evaluated twenty-four paraffin-embedded lung tissue samples from patients who died of COVID-19 (COVID-19 group) and compared them with ten lung tissue samples from patients who died of H1N1pdm09 (H1N1 group) with the immunohistochemical markers mentioned above. In addition, polymorphisms in the Perforin gene were genotyped through Real-Time PCR. Significantly increased tissue immunoexpression of Arginase, CD4, CD68, CD138, Perforin, Sphingosine-1, and IL-4 markers were observed in the COVID-19 group. A significantly lower immunoexpression of CD8 and CD57 was also found in this group. It is suggested that patients who died from COVID-19 had a poor cellular response concerning viral clearance and adaptive response going through tissue repair.

High Prevalence of Hemophagocytic Lymphohistiocytosis in Acute Liver Failure of Infancy.

OBJECTIVES: To investigate the prevalence of hemophagocytic lymphohistiocytosis (HLH) syndrome in pediatric acute liver failure (PALF) of infancy and assess the diagnostic role of rapid immunologic tests, genotype/phenotype correlations, and clinical outcomes. STUDY DESIGN: We retrospectively analyzed 78 children with PALF aged <24 months referred over almost 2 decades. The studied patients with a phenotype of HLH syndrome had a comprehensive immunologic workup, including additional genetic analysis for primary immunologic causes. RESULTS: Thirty of the 78 children had the HLH phenotype and underwent genetic assessment, which demonstrated positive findings in 19 (63.3%), including 9 (30%) with biallelic primary HLH mutations and 10 (33.3%) with heterozygous mutations and/or polymorphisms. The most common form of primary HLH was familial hemophagocytic lymphohistiocytosis (FHL)-2, diagnosed in 6 children, 4 of whom had a c.50delT (p.Leu17ArgfsTer34) mutation in the PRF1 gene. Three patients with primary HLH received genetic diagnoses of FHL-3, Griscelli syndrome, and LRBA (lipopolysaccharide-responsive vesicle trafficking, beach- and anchor-containing) protein deficiency. Overall mortality in the series was 52.6% (10 of 19), and mortality in children with a documented biallelic pathogenic HLH mutation (ie, primary HLH) was 66.6% (6 of 9). Two children underwent liver transplantation, and 4 children underwent emergency hematopoietic stem cell transplantation; all but 1 child survived medium term. CONCLUSIONS: Primary HLH can be diagnosed retrospectively in approximately one-third of infants with indeterminate PALF (iPALF) who meet the clinical criteria for HLH, often leading to their death. The most common HLH type in iPALF is FHL-2, caused by biallelic mutations in PRF-1. The clinical relevance of observed heterozygous mutations and variants of uncertain significance requires further investigation. Prompt hematopoietic stem cell transplantation could be life-saving in infants who survive the liver injury.

The key to egress? Babesia bovis perforin-like protein 1 (PLP1) with hemolytic capacity is required for blood stage replication and is involved in the exit of the parasite from the host cell.

Bovine babesiosis is a tick-borne disease caused by apicomplexan parasites of the Babesia genus that represents a major constraint to livestock production worldwide. Currently available vaccines are based on live parasites which have archetypal limitations. Our goal is to identify candidate antigens so that new and effective vaccines against Babesia may be developed. The perforin-like protein (PLP) family has been identified as a key player in cell traversal and egress in related apicomplexans and it was also identified in Babesia, but its function in this parasite remains unknown. The aim of this work was to define the PLP family in Babesia and functionally characterize PLP1, a representative member of the family in Babesia bovis. Bioinformatic analyses demonstrate a variable number of plp genes (four to eight) in the genomes of six different Babesia spp. and conservation of the family members at the secondary and tertiary structure levels. We demonstrate here that Babesia PLPs contain the critical domains present in other apicomplexan PLPs to display the lytic capacity. We then focused on the functional characterization of PLP1 of B. bovis, both in vitro and in vivo. PLP1 is expressed and exposed to the host immune system during infection and has high hemolytic capacity under a wide range of conditions in vitro. A B. bovis plp1 knockout line displayed a decreased growth rate in vitro compared with the wild type strain and a peculiar phenotype consisting of multiple parasites within a single red blood cell, although at low frequency. This phenotype suggests that the lack of PLP1 has a negative impact on the mechanism of egression of the parasite and, therefore, on its capacity to proliferate. It is possible that PLP1 is associated with other proteins in the processes of invasion and egress, which were found to have redundant mechanisms in related apicomplexans. Future work will be focused on unravelling the network of proteins involved in these essential parasite functions.

Perforin and granzymes in neurological infections: From humans to cattle.

Perforin and granzymes are essential components of the cytotoxic granules present in cytotoxic T lymphocytes and natural killer cells. These proteins play a crucial role in a variety of conditions, including viral infections, tumor immune surveillance, and tissue rejection. Besides their beneficial effect in most of these situations, perforin and granzymes have also been associated with tissue damage and immune diseases. Moreover, it has been reported that perforin and granzymes released during viral infections could contribute to the pathogenesis of diseases. In this review, we summarize the information available on human perforin and granzymes and their relationship with neurological infections and immune disorders. Furthermore, we compare this information with that available for bovine and present data on perforin and granzymes expression in cattle infected with bovine alphaherpesvirus types1 and -5. To our knowledge, this is the first review analyzing the impact of perforin and granzymes on neurological infections caused by bovine herpesviruses.

Síndrome Hemofagocítico en Niños Reporte de Caso / Hemophagocytic Syndromein children: a case report

Introducción:El síndrome hemofagocítico (SHF) es reconocido como un conjunto de signos clínicos y hallazgos laboratoriales que tienen un grave compromiso en la salud y vitalidad de los niños con una incidencia de 1.2 casos/millón/año. Puede pasar subdiagnosticado y confundido con sepsis de foco inespecífico Caso clínico:Niño de 4 años de edad, sin antecedentes de importancia. Ingresado desde el servicio de emergencia por presentar 20 días de fiebre y dolor abdominal. Requirió intubación por franca falla respiratoria y el ingreso a la Unidad de Cuidados Intensivos Pediátricos. Con hipotensión e insuficiencia hepática, pancitopeniay esplenomegalia. Evolución: Se descartaron infecciones bacterianas con policultivos, SARS-Cov 2negativo,se descartaron inmunodeficiencias congénitas y adquiridas.TORCHnegativo, VDRL no reactivo.La prueba de Epstein Barr fue positivo para IgM.Se determinó endocarditis con derrame pericárdico global. Estudio de biopsia medular normocromía, normocitosis, pancitopenia y blastos <5%, sin infiltración tumoral. Se estableció el Diagnóstico de SHFse inicióciclosporina y corticoterapia.Requirió ventilación mecánica por 20 días con período de pronación de 36 horas. Fue dado de alta a pediatríay posteriormente a domicilio, para control por consulta externa. Conclusión: El diagnóstico del SHF es inusual y subestimado al momento de la evaluación clínica. En el presente reporte se asocia a la presencia del Virus Epstein Barr

Introduction: Hemophagocytic syndrome (HPS) is recognized as a set of clinical signs and laboratory findings that have a serious compromise on the health and vitality of children with an incidence of 1.2 cases / million / year. It can be underdiagnosed and confused with sepsis with a non-specific focus. Clinical case: 4-year-old boy, with no significant history. Admitted from the emergency service due to 20 days of fever and abdominal pain. She required intubation due to frank respiratory failureand admission to the Pediatric Intensive Care Unit. With hypotension and liver failure, pancytopenia and splenomegaly. Evolution: Bacterial infections were ruled out with polycultures, SARS-Cov 2 negative, congenital and acquired immunodeficiencies were ruled out. Negative TORCH, non-reactive VDRL. The Epstein Barr test was positive for IgM. Endocarditis with global pericardial effusion was determined. Medullary biopsy study normochromia, normocytosis, pancytopenia, and blasts <5%, without tumor infiltration. The diagnosis of SHF was established, cyclosporine and corticosteroid therapy were started. He required mechanical ventilation for 20 days with a 36-hour pronation period. He was discharged to pediatrics and later at home, for outpatient control. Conclusion: The diagnosis of HHS is unusual and underestimated at the time of clinical evaluation. In this report it is associated with the presence of the Epstein Barr Virus

Fatal familial hemophagocytic lymphohistiocytosis with perforin gene (PRF1) mutation and EBV-associated T-cell lymphoproliferative disorder of the thyroid

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare fatal autosomal recessive disorder of immune dysregulation. The disease presents most commonly in the first year of life; however, symptomatic presentation throughout childhood and adulthood has also been identified. Biallelic mutation in the perforin gene is present in 20%­50% of all cases of FHL. Secondary hemophagocytic lymphohistiocytosis (HLH) in association with hematological malignancies is known; however, whether mutations in HLH-associated genes can be associated with FHL and hematolymphoid neoplasms is not well documented. Also, Epstein­Barr-virus- (EBV) positive systemic T-cell lymphoproliferative disease (SE-LPD) in the setting of FHL is not clearly understood. Here, we present the case of a young boy who presented with typical features of childhood FHL harboring the perforin gene (PRF1) mutation, and had SE-LPD diagnosed on autopsy, along with evidence of recent EBV infection. The patient expired due to progressive disease. Five siblings died in the second or third decade of life with undiagnosed disease. Genetic counseling was provided to the two surviving siblings and parents, but they could not afford genetic testing. One surviving sibling has intermittent fever and is on close follow-up for possible bone marrow transplantation.

Fatal familial hemophagocytic lymphohistiocytosis with perforin gene (PRF1) mutation and EBV-associated T-cell lymphoproliferative disorder of the thyroid.

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare fatal autosomal recessive disorder of immune dysregulation. The disease presents most commonly in the first year of life; however, symptomatic presentation throughout childhood and adulthood has also been identified. Biallelic mutation in the perforin gene is present in 20%-50% of all cases of FHL. Secondary hemophagocytic lymphohistiocytosis (HLH) in association with hematological malignancies is known; however, whether mutations in HLH-associated genes can be associated with FHL and hematolymphoid neoplasms is not well documented. Also, Epstein-Barr-virus- (EBV) positive systemic T-cell lymphoproliferative disease (SE-LPD) in the setting of FHL is not clearly understood. Here, we present the case of a young boy who presented with typical features of childhood FHL harboring the perforin gene (PRF1) mutation, and had SE-LPD diagnosed on autopsy, along with evidence of recent EBV infection. The patient expired due to progressive disease. Five siblings died in the second or third decade of life with undiagnosed disease. Genetic counseling was provided to the two surviving siblings and parents, but they could not afford genetic testing. One surviving sibling has intermittent fever and is on close follow-up for possible bone marrow transplantation.

Cytotoxic CD4+ T-cells during HIV infection: Targets or weapons?

Classically, CD4+ T-cells have been referred as cytokine-producing cells and important players in immune responses by providing soluble factors that potentiate several effector immune functions. However, it is now evident that CD4+ T-cells can also elaborate cytotoxic responses, inducing apoptosis of target cells. Cytotoxic CD4+ T cells (CD4+ CTLs), exhibit cytolytic functions that resemble those of CD8+ T-cells; in fact, there is evidence suggesting that they may have a role in the control of viral infections. In this article, we discuss the role of CD4+ CTLs during HIV infection, where CD4+ CTLs have been associated with viral control and slow disease progression. In addition, we address the implication of CD4+ CTLs in the context of antiretroviral therapy and the partial reconstitution of CD8+ T-cells effector function.

Evaluation of the cytotoxic response mediated by perforin and granzyme B in patients with non-Hodgkin lymphoma.

This study quantified the perforin and granzyme B in patients with non-Hodgkin lymphoma (NHL) at the time of diagnosis. Protein quantification was performed by flow cytometry. NHL patients had a higher number of cytotoxic T lymphocytes (CTLs) expressing perforin as well as a greater number of activated CTLs than the control group. However, intracellular perforin levels in natural killer cells were lower in the NHL patients compared to the control group. Quantitative real time PCR showed that patients had more expression of perforin and granzyme B transcripts compared to the control group. In addition, patients who had expression of both genes below the median found for the NHL group had lower survival rates. Considering this, we believe that perforin and granzyme B are potential prognostic markers in NHL and thus it is fundamental to pay attention to their expressions in these patients.

Linfo-histiocitose hematofagocítica: relato de caso e revisão da literatura / Hemophagocytic lymphohistiocytosis: case report and literature review

A linfo-histiocitose hematofagocítica é uma síndrome pouco comum, caracterizada por descontrolada ativação e proliferação imunopatológica, levando a evidências clínicas e laboratoriais de inflamação extrema. Pode ser causada primariamente por mutações genéticas (linfo-histiocitose hematofagocítica familiar) ou secundariamente, por uma condição esporádica (linfo--histiocitose hematofagocítica adquirida), como infecções e malignidades.O objetivo deste trabalho foi chamar a atenção para a hinfo-histiocitose hematofagocítica em sua forma secundária (adquirida), com discussão de relato de caso e breve revisão da literatura. Em razão da forma secundária da linfo-histiocitose hematofagocítica ser rara e letal, pouco difundida no meio médico-acadêmico, ter apresentação variável e possuir testes que exigem tempo necessário para o diagnóstico, ela constitui desafio para a realização do diagnóstico precoce e do pronto início da imunoquimioterapia necessária à sobrevivência. O tratamento é complicado por curso clínico dinâmico, alto risco de morbidade e recorrência da doença. O prognóstico geralmente é muito ruim, com evolução potencialmente letal em curto período de tempo se não tratada.

Hemophagocytic Lymphohistiocytosis (HLH) is an uncommon syndrome, characterized by uncontrolled immunopathologic activation and proliferation, leading to clinical and laboratory evidence of severe inflammation. It can be primarily caused by genetic mutations (familial HLH), or secondarily, by a sporadic condition (acquired HLH), such as an infection or malignancy. The purpose of the study is to draw the attention to hematophagocytic Lymphohistiocytosis in its secondary (acquired) form, discussing a case report and briefly reviewing the literature. Because the secondary form of hematophagocytic lymphohistiocytosis is rare and lethal, and poorly widespread in the medical-academic area, with variable appearance, and requiring time-consuming diagnostic tests, it represents a challenge for getting an early diagnosis, and immediately starting immunochemotherapy necessary for survival. Treatment is complicated by the dynamic clinical course, high morbidity risk and recurrence. The prognosis is generally very poor, with potentially fatal outcomes in short time if not treated.

Analysis of the -398C/T polymorphism in the perforin gene in oncohematological patients.

BACKGROUND: Recently, single nucleotide polymorphisms (SNPs) were identified in the promoter region of the perforin gene (PRF1) and it was found that the -398T mutant allele is correlated with lower amounts of protein in circulating CD8(+) cytotoxic T lymphocytes. OBJECTIVE: The aim of this study was to investigate the presence of the -398C/T polymorphism in the perforin gene in oncohematological patients. METHODS: Sixty-two patients with hematological malignancies treated at the teaching hospital of the Universidade Federal do Triângulo Mineiro were invited to participate in this study. The identification of the polymorphism was achieved by amplification using polymerase chain reaction, digestion using the TaqI enzyme and electrophoresis in 1% agarose gel. RESULTS: The heterozygous -398C/T polymorphism was identified in 16.7% patients with acute lymphoblastic leukemia, 40% with multiple myeloma, 50% with essential thrombocythemia, 14.3% with Hodgkin's disease, 7.7% with non-Hodgkin lymphoma and 33.3% with chronic lymphocytic leukemia. The homozygous mutant allele was identified in one mulatto individual (25%) with myelodysplastic syndrome. When Afro-Brazilian and Whites were analyzed together, there was a higher frequency of the -398T allele in patients than in healthy individuals (p-value = 0.0291). CONCLUSION: ne patient was homozygous for the -398T allele. Based on these findings, further studies should be conducted to assess whether the presence of this polymorphism may be a risk factor for the development of hematologic malignancies.

Analysis of the -398C/T polymorphism in the perforin gene in oncohematological patients

BACKGROUND: Recently, single nucleotide polymorphisms (SNPs) were identified in the promoter region of the perforin gene (PRF1) and it was found that the -398T mutant allele is correlated with lower amounts of protein in circulating CD8+ cytotoxic T lymphocytes. OBJECTIVE: The aim of this study was to investigate the presence of the -398C/T polymorphism in the perforin gene in oncohematological patients. Methods: Sixty-two patients with hematological malignancies treated at the teaching hospital of the Universidade Federal do Triângulo Mineiro were invited to participate in this study. The identification of the polymorphism was achieved by amplification using polymerase chain reaction, digestion using the TaqI enzyme and electrophoresis in 1 percent agarose gel. RESULTS: The heterozygous -398C/T polymorphism was identified in 16.7 percent patients with acute lymphoblastic leukemia, 40 percent with multiple myeloma, 50 percent with essential thrombocythemia, 14.3 percent with Hodgkin's disease, 7.7 percent with non-Hodgkin lymphoma and 33.3 percent with chronic lymphocytic leukemia. The homozygous mutant allele was identified in one mulatto individual (25 percent) with myelodysplastic syndrome. When Afro-Brazilian and Whites were analyzed together, there was a higher frequency of the -398T allele in patients than in healthy individuals (p-value = 0.0291). CONCLUSION:One patient was homozygous for the -398T allele. Based on these findings, further studies should be conducted to assess whether the presence of this polymorphism may be a risk factor for the development of hematologic malignancies.

Linfo-histiocitose hemofagocítica: tratamento com plasmaferese e gamaglobulina endovenosa / Haemophagocytic lymphohistiocitosis: treatment with plasmapheresis and intravenous immunoglobulin

O presente relato de caso tem como finalidade chamar a atenção de doença grave que frequentemente é confundida com septicemia, no entanto o mecanismo etiológico é decorrente de defeitos genéticos ou associados à resposta imunológica exagerada, decorrente de ação citotóxica de linfócitos T CD8 e histiócitos, acarretando proliferação clonal e ativação de células ”natural killer” (NK). Uma tempestade de linfocinas acontece e como consequência é iniciada uma incontrolável hemofagocitose de todos os elementos sanguíneos, terminando pela infecção secundária do organismo por ausência de destruição de patógenos. A maioria dos casos termina pela morte do paciente; no entanto, relatamos nesse caso a possibilidade de incluirmos a plasmaferese como forma de retirar as linfocinas circulantes, razão do estímulo à destruição celular. O tratamento concomitante com alta dose de imunoglobulina endovenosa também foi realizado

The purpose of the present case report is to call attention to a serious disease that is often mistaken with septicemia, although its etiological mechanism results from genetic defects or is associated with an immune over-reaction, resulting from cytotoxic action of CD8 T lymphocytes and histiocytes, causing clonal proliferation and activation of “natural killer” (NK) cells. There occurs a storm of lymphokines and, as a consequence, an uncontrollable hemophagocytosis of all blood elements, which leads to secondary infection of the organism because of absence of pathogens destruction. Although most of the cases end up in death, in this case we report the possibility of including plasmapheresis as a way to remove the circulating lymphokines, the reason for stimulation of cell destruction. Co-treatment with high dose of intravenous immunoglobulin was performed too

Perfil de citocinas e células imunológicas em pacientes com tuberculose pleural co-infectados ou não pelo HIV / Cytokine and immune cell profile pleural tuberculosis in patients with and without HIV co-infection

Introdução: a tuberculose pleural tem uma evolução benigna, mesmo quando associada à infecção pelo HIV. Com o objetivo de compreender os mecanismos imunológicos envolvidos neste fenômeno, nós comparamos as concentrações de citocinas e subgrupos de células imunológicas no líquido e tecido pleural de pacientes com tuberculose pleural com e sem infecção pelo HIV. Material e métodos: foram incluídos 42 pacientes com o diagnóstico de tuberculose pleural dos quais 12 infectados pelo HIV. A análise imunohistoquímica do tecido pleural foi realizada em 21 pacientes utilizando os seguintes anticorpos monoclonais: anti-CD4, anti-CD8, anti-delta TCR, anti-perforina e anti-fasL. A concentração de citocinas (IL-2,IL-4, IL-10, IL-12 e IFN-) foi medida pelo método ELISA no líquido pleural de 29 pacientes. Resultados: a mediana das proporções de células CD8+ e perforina+ foi superior nos pacientes infectados pelo HIV. A proporção de células CD4+, FasL+ e delta-TCR+ foram semelhantes nos dois grupos. A IL-4 foi indetectável em todos os pacientes. Três de nove pacientes infectados pelo HIV apresentaram uma concentração de IL-2 superior a 40 pg/ml (p=0,02). Conclusões: as concentrações de IFN-, IL-10 e IL-12 foram semelhantes nos dois grupos. A citotoxicidade mediada pela perforina e a IL-2 parecem ter um papel importante na proteção contra Mycobacterium tuberculosis nos estádios iniciais da infecção pelo HIV. As células CD8+ do tecido pleural podem ser uma fonte alternativa de síntese de IFN- em pacientes com tuberculose pleural co-infectados pelo HIV.

Introduction: pleural tuberculosis (TB) has a benign course whether associated or not to HIV infection. To understand the immune mechanisms involved in this phenomenon, we compared cytokine concentrations and subsets of immune cells in the pleural fluid/tissue from patients with TB pleurisy with and without HIV co-infection. Material and methods: forty-two patients diagnosed with pleural TB were included, twelve of whom were HIV-infected. Immunohistochemical analysis of pleural tissue was performed in 21 patients with TB pleurisy with and without HIV co-infection. Material and methods: forty-two patients diagnosed with pleural TB were included, twelve of whom were HIV-infected. Immunohistochemical analysis of pleural tissue was performed in 21 patients using the following monoclonal antibodies: anti-CD4, anti CD-8, anti-delta TCR, anti-perforin and anti FasL. Cytokine (IL-2, OÇ-4, IL-10, IL-12 amd IFN-) concentration was measured by the ELISA method in the pleural fluid of 29 patients. Results: the median proportions of CD8+ and perforin + cells were higher in HIV-infected patients. The proportions of CD4+, FasL+ and delta-TCR+ cells were similar in both groups. IL-4 was undetectable in all patients. Three out of nine HIV-infected patients had IL-2 concentration ouver 40pg/ml (p=0.02). Conclusion: the concentrations of IFN-, IL-10 and IL-12 were similar in both groups. Perforin-mediated cytotoxicity and IL-2 may play an important role in protection against Mycobacterium tuberculosis in the early stages of HIV infection. Pleural CD8+ cells may be an alternative source for IFN- in HIV-infected patients with tuberculosis.