Recombinant CD5 and CD6 Ectodomains Induce Antiparasitic and Immunomodulatory Effects in Secondary Cystic Echinococcosis.

Scavenger receptors participate in a wide range of biological functions after binding to multiple non-self or altered self-ligands. Among them, CD5 and CD6 are lymphocyte scavenger receptors known to interact with different microbial-associated molecular patterns, and the administration of the recombinant soluble ectodomains of human CD5 (rshCD5) and/or CD6 (rshCD6) has shown therapeutic/prophylactic potential in experimental models of fungal, bacterial and echinococcal infections. The latter is a zoonosis caused by the larval stage of the cestode parasite Echinococcus granulosus sensu lato, which in humans can induce secondary cystic echinococcosis (CE) after the spillage of protoscoleces contained within fertile cysts, either spontaneously or during surgical removal of primary hydatid cysts. Herein, we have analysed the mechanisms behind the significant protection observed in the mouse model of secondary CE following prophylactic administration of rshCD5 or rshCD6. Our results show that both molecules exhibit intrinsic antiparasitic activities in vitro, as well as immunomodulatory functions during early secondary CE, mainly through Th1/Th17 cytokine bias and promotion of peritoneal polyreactive antibodies. These data support the relevance of the parasite components bound by rshCD5 and rshCD6, as well as the potential of their prophylactic administration as a useful strategy to reduce secondary CE in patients.

Latent Tuberculosis Patients Have an Increased Frequency of IFN-γ-Producing CD5+ B Cells, Which Respond Efficiently to Mycobacterial Proteins.

Tuberculosis (TB) remains a public health problem worldwide and is one of the deadliest infectious diseases, only after the current COVID-19 pandemic. Despite significant advances in the TB field, there needs to be more immune response comprehension; for instance, the role played by humoral immunity is still controversial. This study aimed to identify the frequency and function of B1 and immature/transitional B cells in patients with active and latent TB (ATB and LTB, respectively). Here we show that LTB patients have an increased frequency of CD5+ B cells and decreased CD10+ B cells. Furthermore, LTB patients stimulated with mycobacteria's antigens increase the frequency of IFN-γ-producing B cells, whereas cells from ATB do not respond. Moreover, under the mycobacterial protein stimulus, LTB promotes a pro-inflammatory environment characterized by a high level of IFN-γ but also can produce IL-10. Regarding the ATB group, they cannot produce IFN-γ, and mycobacterial lipids and proteins stimulate only the IL-10 production. Finally, our data showed that in ATB, but not in LTB, B cell subsets correlate with clinical and laboratory parameters, suggesting that these CD5+ and CD10+ B cell subpopulations have the potential to be biomarkers to differentiate between LTB and ATB. In conclusion, LTB has increased CD5+ B cells, and these cells can maintain a rich microenvironment of IFN-γ, IL-10, and IL-4. In contrast, ATB only maintains an anti-inflammatory environment when stimulated with mycobacterial proteins or lipids.

Linfoma difuso de células grandes B CD5 positivo con compromiso prostático: una recurrencia inusual / CD5 positive Diffuse large B cell lymphoma with prostate involvement: An unusual recurrenc

Introducción: El Linfoma de células grandes B CD5 positivo (LDCGB CD5+) constituye una patología rara y agresiva con pobre respuesta a la quimioinmunoterapia. Objetivo: Describir un caso con diagnóstico de LDCGB CD5+ con recurrencia inusual prostática. Caso clínico: Paciente varón de 61 años con sintomatología de dolor abdominal y síntomas B. Los estudios de imagen mostraron adenopatías mediastinales y retroperitoneales. El informe patológico fue compatible LDCGB CD5+, recibiendo terapia de primera línea con R-CHOP logrando remisión completa, con recaída precoz prostática confirmada por inmunohistoquímica. Posteriormente, inicia terapia de rescate con R-ICE, con pobre respuesta y deterioro del estado funcional. Conclusiones: El LDCGB CD5 + representa una patología infrecuente y agresiva, siendo la recaída en próstata un evento muy inusual, es por ello que los exámenes clínicos exhaustivos y anatomo-patológico son esenciales para un diagnóstico certero. A la fecha, la respuesta a terapias estándar o de mayor intensidad son desalentadoras, por lo que es necesario un mayor número de estudios a futuro(AU)

Introduction: CD5 positive Large B-cell Lymphoma (CD5 + DLBCL) constitutes a rare and aggressive pathology with poor response to chemoimmunotherapy. Objective: To describe a case with a diagnosis of CD5 + DLBCL with an unusual recurrence in the prostate. Clinical case: A 61-year-old male presented abdominal pain and B symptoms. Imaging studies showed mediastinal and retroperitoneal lymphadenopathy. The pathology informed a CD5+ DLBCL diagnosis, receiving first-line R-CHOP treatment and achieving complete remission, with prostatic early relapse confirmed by immunohistochemistry. Therefore, he received R-ICE as rescue treatment with poor response and performance status decline. Conclusions: CD5 + LDCGB represents a rare and aggressive disease, being the prostate relapse a very unusual event, in which the exhaustive clinical and pathological workup is essential for an accurate diagnosis. To date, the response to standard or higher-intensity therapies is disappointing, so more studies are needed in the future(AU)

Interactome analysis of CD5 and CD6 ectodomains with tegumental antigens from the helminth parasite Echinococcus granulosus sensu lato.

Echinococcus granulosus sensu lato (s.l.) is a cestode parasite affecting both human and livestock health. Recombinant ectodomains of human scavenger receptors CD5 (rshCD5) and CD6 (rshCD6) were previously reported to bind its tegumental antigens and to exert prophylactic effects in a murine model of infection. Although the properties of mammalian scavenger receptors include the binding to diverse pathogen-derived structures, their interaction with helminth parasites has been scarcely explored. Therefore, we report here a search for CD5 and CD6 interactors within E. granulosus s.l. antigens. Mass spectrometry analysis of pull-downs from soluble tegumental components with biotinylated rshCD5 and rshCD6 resulted in 17 and 11 overrepresented interactors, respectively, 8 of which were shared. The interactors included previously reported protective molecules against E. granulosus s.l. and/or other helminths. Similar studies performed with 11-mer peptides mapping to each of the three extracellular scavenger domains of CD5 and CD6 allowed an estimated molecular topology of the interactions. In conclusion, the fact that most helminth interactors identified for rshCD5 and rshCD6 were already reported as vaccine candidates or pharmacological targets against different helminthiases, supports the view that their beneficial effects in experimental infection results from binding to multiple relevant tegumental antigens.

Active fractions of mannoproteins derived from yeast cell wall stimulate innate and acquired immunity of adult and elderly dogs.

Nutritional intervention in older dogs aims to increase lifespan and improve life quality as well as delay the development of diseases related to ageing. It is believed that active fractions of mannoproteins (AFMs) obtained through extraction and fractionation of yeast cell walls (Saccharomyces cerevisiae) may beneficially modulate the immune system. However, studies that have evaluated this component and the effects of ageing on the immune system of dogs are scarce. This study aimed to evaluate the immunological effects of AFMs in adult and elderly dogs. Three extruded iso-nutrient experimental diets were formulated: without addition of AFM (T0); with AFM at 400 mg/kg (T400); and with AFM at 800 mg/kg (T800). Thirty-six beagle dogs were used, and six experimental treatments, resulting in combinations of age (adult and elderly) and diet (T0, T400, and T800), were evaluated. On days zero, 14, and 28, blood samples were obtained for leucocyte phenotyping and phagocytosis assays. On days zero and 28, a lymphoproliferation test, quantification of reactive oxygen (H2O2) and nitrogen (NO) intermediate production, evaluation of faecal immunoglobulin A (IgA) content, and a delayed cutaneous hypersensitivity test (DCHT) were performed. Statistical analyses were performed with SAS software. Repeated measure variance analyses were performed, and means were compared by the Tukey test. Values of P ≤ 0.05 were considered significant, and values of P ≤ 0.10 were considered tendencies. Dogs fed T400 tended to have higher neutrophilic phagocytic activity than dogs fed T800 (P = 0.073). Regarding reactive oxygen intermediates, bacterial lipopolysaccharide (LPS)-stimulated neutrophils from animals that were fed T400 had a tendency to produce more H2O2 than those from animals fed the control diet (P = 0.093). Elderly dogs, when compared to adult dogs, had lower absolute T and B lymphocyte counts, lower auxiliary T lymphocyte counts, and higher cytotoxic T lymphocyte counts (P < 0.05). A significant effect of diet, age, and time with saline inoculation was noted for the DCHT. There was no effect of diet or age on faecal IgA content in dogs. This study suggests beneficial effects of mannoproteins on the specific and nonspecific immune responses in adult and elderly dogs.

Concentration-dependent effect of bleaching agents on the immunolabelling of interleukin-6, interleukin-17 and CD5-positive cells in the dental pulp.

AIM: To evaluate lymphocyte-like cell activation (CD5-positive cells) and the expression of interleukin (IL)-6 and IL-17 in the pulp after tooth bleaching with two concentrations of hydrogen peroxide (H2 O2 ). METHODOLOGY: The right and left maxillary molars from 40 rats were treated randomly with bleaching gel with 20% H2 O2 (BLUE group, 1 application of 50 min), 35% H2 O2 (MAXX group, three applications of 15 min), or placebo gel (control). After 2 and 30 days, the rats were killed (n = 10), and the jaws were processed for histological and immunohistochemistry analysis of the pulp tissue. The scores of inflammation and immunolabelling (IL-6/IL-17) were submitted to Mann-Whitney and Kruskal-Wallis followed Dunn tests, respectively; anova tests were used for comparisons of number of CD5-positive cells and pulp chamber area values (P < 0.05). RESULTS: At 2 days, 60% of specimens of the BLUE group were associated with moderate inflammation in pulp horns, and in the MAXX group with necrosis (P < 0.05). At 30 days, the pulp was organized, and tertiary dentine was formed. The MAXX group had superior immunolabelling of IL-17 at 2 days differing significantly from other groups (P < 0.05). At 2 days, 90% of the specimens of the BLUE group had moderate immunolabelling of IL-6, and 50% of the MAXX group had severe immunolabelling, both significantly different from the control (P < 0.05). There was no significant difference between the groups at 30 days (P > 0.05). CD5-positive cells were present at 2 and 30 days, particularly in the bleached groups (P < 0.05), without significant difference between time periods (P > 0.05). CONCLUSIONS: IL-6 and IL-17 participated in inflammation in the pulp tissue of rats after tooth bleaching, particularly at 2 days. The immunolabelling was greater with increasing H2 O2 concentration. This process was accompanied by the prolonged activation of CD5-positive cells.

Functional requirement of tyrosine residue 429 within CD5 cytoplasmic domain for regulation of T cell activation and survival.

CD5 has been mainly described as a negative regulator of TCR and BCR signaling and recent evidence has shown an important role for this receptor in delivering pro-survival signals. However, the molecular mechanisms underlying these processes remain unresolved. TCR crosslinking leads to phosphorylation of three tyrosine residues within the cytoplasmic tail of CD5 (Y429, Y441 and Y463) leading to the recruitment of signaling molecules like PI3K, c-Cbl and RasGAP; nevertheless, the role of these residues in T cell survival has not yet been assessed. In this study, we show that alanine-scanning mutagenesis of such tyrosine residues, either singly or in combination, leads to an increased thymocyte cell death with or without α-CD3 stimulation. Remarkably, the T-cell death observed with each individual tyrosine mutant was Caspase 3-independent. Furthermore, Y429 mutation resulted in a hyper-phosphorylation of ERK suggesting that this tyrosine residue regulates cell survival through down modulation of TCR signaling. Mutation of Y441 or Y463 did not induce hyper-responsiveness to TCR activation, indicating that they promoted T-cell survival by a TCR signal-independent pathway. Our results show that three tyrosine-based domains within CD5 cytoplasmic tail promote T-cell survival through non-overlapping mechanisms. This study also reveals that Y429 domain of CD5, previously described as a "pseudo ITAM", is functionally an ITIM domain in T cells.

Linfoma B difuso de células grandes: factores pronósticos en la era del rituximab / Diffuse large B cell lymphoma: prognostic factors in the rituximab era

Introducción: la inclusión del rituximab para el tratamiento del linfoma B difuso de células grandes generó la necesidad de reevaluar los factores pronósticos que se empleaban convencionalmente, y la de explorar otros que podrían resultar útiles para establecer el pronóstico. Objetivo: describir los principales factores clínicos, hematológicos, bioquímicos e inmunohistoquímicos que han sido útiles para el pronóstico en estudios de seguimiento de pacientes con linfoma B difuso de células grandes tratados con esquemas de quimioterapia que contenían rituximab. Resultados: entre los factores con significancia para el pronóstico se encontraron el Índice Pronóstico Internacional (IPI) revisado, la infiltración de la médula ósea, la presencia de masa voluminosa, la expresión de CD5 y el porcentaje de expresión de Ki-67; en contraste, es controversial la aplicación de otros factores como el IPI convencional, la expresión de Bcl-2, Bcl-6 y el perfil inmunohistoquímico.

Introduction: The inclusion of rituximab for treatment of diffuse large B cell lymphoma (DLBCL) generated the need to re-assess the conventionally employed prognostic factors and to explore others that could be useful for prognostic purposes. Objective: To describe the most important clinical, hematological, biochemical and immunohistochemical factors that have been useful for prognostic purposes in follow-up studies of patients with DLBCL treated with chemotherapy plus rituximab. Results: The following factors were found to have prognostic significance: the revised International Prognostic Index, bone marrow infiltration, the presence of a bulky mass, CD5 expression and the percentage of Ki-67 expression. Contrariwise, the application of other factors remains controversial: conventional IPI, Bcl-2 and Bcl-6 expression, and the immunohistochemical profile.

Use of CD25 as an immunohistochemical marker for acquired ocular toxoplasmosis / Uso do CD25 como um marcador imuno-histoquímico de toxoplasmose ocular adquirida

PURPOSE: Toxoplasmosis is the most common cause of posterior infectious uveitis worldwide. It is often impossible to determine its congenital or acquired nature. Interleukin-2 (IL-2) in peripheral blood has been described as a possible marker for acquired toxoplasmosis. The purpose of this study is to evaluate the histopathological characteristics of ocular toxoplasmosis cases using CD25 as a marker for the expression of interleukin-2. METHODS: Ten formalin-fixed, paraffin-embedded enucleated globes from ten immunocompetent patients with clinical diagnosis of toxoplasmosis were evaluated. Four patients had the acquired form of ocular toxoplasmosis (positive IgM) while six were IgM negative and IgG positive for toxoplasmosis. Histopathological slides were reviewed for the extension of the retinal necrosis, number of toxo cysts, the granulomatous inflammatory reaction, the presence of T and B cells within the choroid and the IL-2 expression. Immunohistochemistry using monoclonal antibodies was performed to observe the expression of CD4, CD8, CD20, CD25, and CD68. RESULTS: The histopathological evaluation disclosed no differences between acquired and the other ocular toxoplasmosis cases regarding the characteristics studied. However, CD25 showed a higher expression of IL-2 on the 4 acquired cases of ocular toxoplasmosis compared to the remainders. CONCLUSIONS: To the best of our knowledge, this is the first report showing that the use of CD25 as a marker for interleukin-2 could differentiate acquired ocular toxoplasmosis.

OBJETIVO: Toxoplasmose é a causa mais comum de uveíte posterior no mundo. Em grande parte dos casos, não é possível determinar se a doença ocular é devida a um quadro congênito ou adquirido. Interleucina-2 (IL-2) no sangue periférico foi descrita como um possível marcador de toxoplasmose adquirida. O objetivo deste estudo foi avaliar as características de casos de toxoplasmose usando CD25 como um marcador da expressão de interleucina-2. MÉTODOS: Dez olhos enucleados fixados com formalina e embebidos em parafina de dez pacientes imunocompetentes com diagnóstico clínico de toxoplasmose ocular foram examinados. Quatro pacientes tinham a forma adquirida (IgM positivo) enquanto 6 eram IgM negativo e IgG positivo para toxoplasmose. Cortes histopatológicos foram avaliados quanto a extensão de necrose retiniana, número de cistos de T. gondii, reação granulomatosa e presença de células B e T na coróide, bem como a expressão de interleucina-2. Estudo imuno-histoquímico utilizando anticorpos monoclonais foi realizado para determinar a expressão de CD4, CD8, CD20, CD25 e CD68. RESULTADOS: A avaliação histopatológica não mostrou diferenças entre os casos de toxoplasmose ocular com relação às características avaliadas mencionadas anteriormente. Entretanto, CD25 revelou maior expressão de interleucina-2 nos 4 casos adquiridos comparado com os demais. CONCLUSÕES: Expressão elevada de CD25 foi encontrada em todos os casos de toxoplasmose ocular adquirida. Assim, o uso de CD25 como marcador da interleucina-2 pode ser uma ferramenta útil para diferenciar toxoplasmose ocular congênita de adquirida.

Validación del ultramicrométodo inmunocitoquímico mediante la citometría de flujo para el diagnóstico de la leucemia linfoide crónica CD5+ / Validation of immunocytochemical ultramicromethod by flux cytometry for diagnosis of DC5+chronic lymphoid leukemia

Se estudiaron 18 pacientes con el diagnóstico de LLC-B, CD5+ procedentes del Instituto de Hematología e Inmunología y del Servicio de Hematología del Hospital Clinicoquirúrgico Hermanos Ameijeiras, en edades comprendidas entre 55 y 80 años. Se utilizó como control un individuo supuestamente sano. La CF se realizó en un FaCScan (Becton Dickinson, EE.EUU.) mediante un análisis de la reacción con los anticuerpos monoclonales (AcMos) en la ventana de la población linfoide.9 El panel de AcMos incluyó: anti-CD3, anti-CD5 y anti-CD19. Algunos AcMos estaban conjugados con ficoeritrina (RPE) y otros con isotiocianato de fluoresceína (FITC). La lectura se realizó mediante la adquisición de 100 000 células en cada tubo. Cada marcador de membrana se consideró positivo si un porcentaje superior al 20 por ciento de los linfocitos expresaban el antígeno. Los resultados de nuestro trabajo demuestran una expresión antigénica similar en el inmunofenotipaje de la LLC-B, CD5+ por ambos métodos, lo que nos permite concluir que el método UMICIQ utilizado en nuestro laboratorio resulta confiable para el diagnóstico inmunológico de esta hemopatía maligna, y constituye una variante técnica alternativa para la caracterización fenotípica en esta y otras enfermedades, fundamentalmente en los laboratorios en los que, por su alto costo, no se dispone de un citómetro de flujo. La caracterización precisa de las células linfoides por métodos inmunofenotípicos, los avances en las técnicas citogenéticas y de biología molecular, contribuirán significativamente a un mejor diagnóstico y tratamiento de estos pacientes

Expresión fenotípica de las moléculas CD5 y CD6 en la leucemia linfoide crónica B-CD5+ / The B-CD5+ chronic lymphoid leukemia related to the phenotype expression

Las moléculas CD5 y CD6 tienen función coestimuladora y muestran homología en su estructura. Se evaluó la expresión de la molécula CD6 mediante el uso del anticuerpo monoclonal anti-CD6 (T1) en el inmunofenotipaje celular de pacientes con leucemia linfoide crónica By se comparó con la expresión de la molécula CD5.Los resultados demuestranuna homología en la expresión fenotípica de ambas moléculas, CD5 y CD6, lo que asociado con que ambos receptores linfocitarios se encuentran físicamente vinculados, permite sugerir que la molécula CD6 constituye un marcador biológico de interés en la evaluación del pronóstico y la posibilidad de nuevas variantes terapéuticas en esta enfermedad(AU)

CD5 and CD6 molecules have a co-stimulant function and show homology in structure. We assessed CD6 molecule expression using anti-CD6 (T1) monoclonal antibody in the cellular immunophenotyping from patients presenting B chronic lymphoid leukemia, and it was compared to CD5 molecule expression. Results show a homology in phenotype expression of both molecules (CD5 and CD6), what associated with the fact that both lymphocyte receptors are physically linked, allow to suggest that CD6 molecule is a interesting biological marker in prognosis assessment, and the possibility of new therapeutic variants in this disease(AU)

Expresión fenotípica de las moléculas CD5 y CD6 en la leucemia linfoide crónica B-CD5+ / The B-CD5+ chronic lymphoid leukemia related to the phenotype expression

Las moléculas CD5 y CD6 tienen función coestimuladora y muestran homología en su estructura. Se evaluó la expresión de la molécula CD6 mediante el uso del anticuerpo monoclonal anti-CD6 (T1) en el inmunofenotipaje celular de pacientes con leucemia linfoide crónica By se comparó con la expresión de la molécula CD5.Los resultados demuestranuna homología en la expresión fenotípica de ambas moléculas, CD5 y CD6, lo que asociado con que ambos receptores linfocitarios se encuentran físicamente vinculados, permite sugerir que la molécula CD6 constituye un marcador biológico de interés en la evaluación del pronóstico y la posibilidad de nuevas variantes terapéuticas en esta enfermedad.

CD5 and CD6 molecules have a co-stimulant function and show homology in structure. We assessed CD6 molecule expression using anti-CD6 (T1) monoclonal antibody in the cellular immunophenotyping from patients presenting B chronic lymphoid leukemia, and it was compared to CD5 molecule expression. Results show a homology in phenotype expression of both molecules (CD5 and CD6), what associated with the fact that both lymphocyte receptors are physically linked, allow to suggest that CD6 molecule is a interesting biological marker in prognosis assessment, and the possibility of new therapeutic variants in this disease.

Detection of CD5 in B-cell chronic lymphoproliferative diseases by flow cytometry: a strong expression in B-cell chronic lymphocytic leukemia

PURPOSE: CD5 is a T cell marker, aberrantly express in B cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL). Other chronic B cell malignancies including hairy cell leukemia (HCL) and B cell prolymphocytic leukemia (B-PLL) are CD5 negative or express this antigen in a weak way. In this study, CD5 expression was investigated in leukemic cells from 42 patients with chronic B cell lymphoproliferative disease. METHODS: We studied the CD5 expression in leukemic cells from 42 patients with chronic B-cell malignancies by flow cytometry. Demographic features such as age, sex and clinical date were also analyzed. RESULTS: There were 22 males and 20 females. The immunophenotyping showed that 35 cases were B-CLL, 3 B-PLL and HCL and one patient was MCL. CD5 expression was present in all B-CLL and MCL. Low expression of CD5 was observed in one patient with B-PLL and negative in all cases of HCL. CONCLUSION: Our date demonstrated that CD5 expression can help distinguish among B-CLL from HCL and B-PLL, but is similar expressed in MCL.

OBJETIVOS: CD5 é um marcador normalmente expresso nas células T e de forma aberrante nas células B da leucemia linfocítica crônica (LLC) e no linfoma de células do manto (LCM). Outras doenças linfoproliferativas crônicas como a hairy cell leukemia (HCL) e leukemia prolinfocítica de células B (LPL-B), são geralmente CD5 negativas ou expressam fracamente este antígeno. Neste trabalho investigou-se o padrão de expressão do CD5 em 42 pacientes com doenças linfoproliferativas crônicas de células B (DLC-B). METODOS: Investigamos a expressão de CD5 em células leucêmicas de 42 pacientes com DLC-B através da citometria de fluxo. Dados demográficos, tais como idade e sexo, bem como dados clínicos e laboratoriais também foram analisados. RESULTADOS: A imunofenotipagem mostrou que 35 casos foram LLC, 3 LPL-B, 3 HCL e um caso de LMC. O CD5 mostrou-se fortemente expresso em todos os casos de LLC e LMC. Baixa expressão desse antígeno foi observada em um caso de LPL-B, mostrando-se negativamente expresso em todos os casos de HCL. CONCLUSÃO: Nossos resultados demonstram que o padrão de expressão do CD5 pode auxiliar na distinção entre LLC da HCL e LPL-B, sendo no entanto similares na HCL e LCM.

Detection of CD5 in B-cell chronic lymphoproliferative diseases by flow cytometry: a strong expression in B-cell chronic lymphocytic leukemia

PURPOSE: CD5 is a T cell marker, aberrantly express in B cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL). Other chronic B cell malignancies including hairy cell leukemia (HCL) and B cell prolymphocytic leukemia (B-PLL) are CD5 negative or express this antigen in a weak way. In this study, CD5 expression was investigated in leukemic cells from 42 patients with chronic B cell lymphoproliferative disease. METHODS: We studied the CD5 expression in leukemic cells from 42 patients with chronic B-cell malignancies by flow cytometry. Demographic features such as age, sex and clinical date were also analyzed. RESULTS: There were 22 males and 20 females. The immunophenotyping showed that 35 cases were B-CLL, 3 B-PLL and HCL and one patient was MCL. CD5 expression was present in all B-CLL and MCL. Low expression of CD5 was observed in one patient with B-PLL and negative in all cases of HCL. CONCLUSION: Our date demonstrated that CD5 expression can help distinguish among B-CLL from HCL and B-PLL, but is similar expressed in MCL.

OBJETIVOS: CD5 é um marcador normalmente expresso nas células T e de forma aberrante nas células B da leucemia linfocítica crônica (LLC) e no linfoma de células do manto (LCM). Outras doenças linfoproliferativas crônicas como a hairy cell leukemia (HCL) e leukemia prolinfocítica de células B (LPL-B), são geralmente CD5 negativas ou expressam fracamente este antígeno. Neste trabalho investigou-se o padrão de expressão do CD5 em 42 pacientes com doenças linfoproliferativas crônicas de células B (DLC-B). METODOS: Investigamos a expressão de CD5 em células leucêmicas de 42 pacientes com DLC-B através da citometria de fluxo. Dados demográficos, tais como idade e sexo, bem como dados clínicos e laboratoriais também foram analisados. RESULTADOS: A imunofenotipagem mostrou que 35 casos foram LLC, 3 LPL-B, 3 HCL e um caso de LMC. O CD5 mostrou-se fortemente expresso em todos os casos de LLC e LMC. Baixa expressão desse antígeno foi observada em um caso de LPL-B, mostrando-se negativamente expresso em todos os casos de HCL. CONCLUSÃO: Nossos resultados demonstram que o padrão de expressão do CD5 pode auxiliar na distinção entre LLC da HCL e LPL-B, sendo no entanto similares na HCL e LCM.