A distinct large granular lymphocyte (LGL)/NK-associated (NKa) abnormality characterized by membrane CD4 and CD8 coexpression

In a study of 870 individual patients with either lymphocytosis (excluding known lymphoproliferative disease), increased proportions of blood lymphocytes with granular morphology (LGL), or neutropenia, 14 cases were found with abnormally increased CD3+CD4+CD8+ components. Eleven of these were further investigated and 10 shown in follow-up studies to be persistent in nature. Morphological assessments revealed increased LGL in 9/11 cases, and in seven of these > 50% lymphocytes had discernable cytoplasmic granulation. Immunophenotypic studies indicated that CD8 expression by CD4+ lymphocytes in these patients was of low density (CD8dim+), and that both the CD4+CD8- and CD4+CD8dim+ fractions in each patient was characterized by a CD11b+CD16-CD56+CD57+ composite NK-associated (NKa) phenotype (in contrast to normal CD4+CD8- blood lymphocytes and CD4+CD8+ thymocytes which were consistently CD11b-CD16-CD56-CD57-). TCR genotypic studies revealed rearranged components (beta plus gamma, or beta alone) in 5/11 cases, but there were no obvious relationships between TCR configuration (including rearranged band densities) and immunophenotypes, absolute lymphocyte or neutrophil numbers, the proportions of blood LGL, or the proportions of CD4+ cells coexpressing CD8. The occurrence of identical NKa phenotypic profiles in both germline and rearranged TCR cases does, however, suggest the possibility of an evolutionary process from a non-clonal expansion to a clonal state. Serum studies, including soluble CD4, CD8 and IL2-R concentrations and autoantibody investigations, of representative germline and rearranged TCR cases failed to indicate any consistent abnormalities, but there was some suggestion for the existence of a chronic reactive process in some of the patients with germline TCR. These findings suggest that expanded LGL/NKa+ components with phenotypic evidence of CD4/CD8 coexpression should be regarded as a distinct diagnostic category and that persistent CD4+CD8+ abnormalities with germline TCR should be monitored for possible clonal transition.     

Transient and persistent expansions of large granular lymphocytes (LGL) and NK-associated (NKa) cells: the Yorkshire Leukaemia Group study

Summary. A survey of 870 different adult blood samples (primarily from patients with non-haematological disorders) found that 269 (31%) had increased proportions (>25%) and/or absolute numbers (>1.0 × 10⁹/l) of morphologically-defined large granular lymphocytes (LGL), and/or pheno-typically-defined NK-associated (NKa) cells. Of these, 112 were re-analysed at least 6 months after initial presentation and were classified as‘persistent’(92/112) or ‘transient’(20/112) according to whether or not the original abnormality was still present. Lymphocyte counts in most patients with persistent abnormalities were within normal limits (18/92) or slightly increased (68/92), with only six having a lymphocytosis exceeding 10.0 × 10⁹/l. With the exception of five persistent LGL expansions in which the granular lymphocytes did not express NKa determinants (designated LGL⁺NKa-), the remaining 87 cases could be phenotypically grouped according to their primary abnormality as CD8⁺NKa⁺ (n = 33), CD4⁺ NKa⁺ (n=14), CD8^dim+NKa⁺ (n=7) or CD8^?NKa⁺ (n=33). TCR genotypic studies in 58 patients showed that the 16 patients with rearranged TCR components were restricted to the CD8⁺NKa⁺ group and that, in most of these, the CD8⁺ fraction showed abnormal relative CD16/CD56 expression. Persistent neutropenia (n=15) also appeared to be associated with primary abnormalities of CD8⁺NKa⁺ cells (12/15). with 10 of these additionally showing rearranged TCR genes. In contrast, persistently increased CD8^dim+NKa⁺ and CD8^–NKa⁺ components did not appear to phenotypically differ from their corresponding ‘counterparts’in normal bloods or in patients with transient LGL/NKa⁺ abnormalities. This survey has therefore established that persistent LGL/NKa⁺ abnormalities are considerably more common than suggested in published work, that a high proportion of patients with expanded CD8⁺NKa⁺ components, with quite diverse clinical histories, show evidence of clonal lymphoid populations, and that the clonal nature of such disorders appears to be associated with abnormal NKa phenotypic patterns.     

Persistent expansions of CD4+ CD8+ peripheral blood T cells

CD4+ CD8+ cells are present during T cell differentiation in the thymus. Less than 2% of normal T cells that coexpress CD4 and CD8 also are released in the circulation and are present in the peripheral blood. In this study, nine individuals are described that manifested persistent expansions (11% to 43%) of circulating CD4+ CD8+ T cells that in three cases had large granular lymphocyte (LGL) morphology in the absence of either lymphocytosis or overt lymphoproliferative disorders. Southern blot hybridization of enriched CD4+ CD8+ cells with T-cell receptor beta (TCR beta) and TCR gamma probes showed that most cases had the 12-kb Eco RI germinal band deleted or of decreased intensity. In several individuals new TCR beta-specific bands of different intensity and distinct from case to case suggested either monoclonal or oligoclonal and polyclonal expansions. Immunophenotypic analysis showed that in 7 out of 9 cases the CD4+ CD8+ T cells presented with CD8 dim expression. Furthermore, all the CD4+ CD8+ cells did not express many of the known activation antigens (low or absent CD25, CD38, CD71, HLA-DR), whereas they expressed high levels of CD2, CD29, CD56, and CD57. In addition, the CD4+ CD8+ cells of 5 out of 9 subjects coexpressed CD45RA and CD45RO suggesting that these cells might be "frozen" in an intermediate state between naive and memory T cells. In conclusion, the present CD4+ CD8+ cases fall within a larger spectrum of disorders ranging from apparently normal to reactive or proliferative situations and encompassing cells with LGL morphology or LGL-associated antigens expression either in the presence or in the absence of absolute lymphocytosis that deserve careful follow-up investigations.     

A biclonal large granular lymphocyte (LGL)/NK-associated (NKa) disorder of CD4+ and CD8+ lymphocyte subpopulations characterized by the simultaneous presence of distinct TCR rearrangements

Summary. This communication reports a patient with concomitant expansions of CD4⁺ and CD8⁺ large granular lymphocytes. Immunological analyses revealed that the abnomally increased CD4⁺ LGL fraction was phenotypically similar to other reported persistent CD4⁺ LGL expansions, whereas the phenotypic profile for the CD8⁺ LGL component was unusual. of particular note was the finding that both the CD4⁺ and CD8⁺ LGL fractions showed high membrane the CD45RO isoform expression, thus suggesting their 'primed' status. Molecular biology studies of immunomagnetically fractionated cells using a Tγ9 TCR gamma gene primer further revealed that the CD4⁺ and CD8⁺ components were both clonal but showed different patterns of rearrangement It is suggested that the simultaneous presence of CD4⁺ and CD8⁺ clonal populations are unlikely to have been derived from a common progenitor and that they reflect expansions of functionally restricted subpopulations     

Biphenotypic leukemic lymphocyte precursors in CD2+CD19+ acute lymphoblastic leukemia and their putative normal counterparts in human fetal hematopoietic tissues

During detailed immunophenotypic analyses of marrow blasts from 336 acute lymphoblastic leukemia (ALL) patients, a very small percentage of cases reactive with B-cell-directed as well as T-cell-directed monoclonal antibodies (MoAbs) were identified. Five ALL cases were biphenotypic since they coexpressed CD2 (Tp50) and CD19 (Bp95) antigens at the single-cell level. The composite immunophenotype of these biphenotypic ALL cases was [TdT+HLA-ABC+CD2+CD3-CD10+CD13-CD14-CD16- CD19+CD20+ ++-CD21-CD33-CD34+Bgp95-C mu- slg-]. Low-molecular-weight B- cell growth factor (LMW-BCGF), recombinant interleukin-2 (rIL-2), and rIL-3 stimulated the proliferative activity of biphenotypic leukemic lymphocyte precursors without inducing differentiation. In the presence of the phorbol ester TPA, leukemic blasts from two cases differentiated along the B precursor pathway to the [CD2-CD10+CD19+CD20+C mu+slg-] pre- B cell stage. Biphenotypic ALL cases did not share a common configuration and gene rearrangement pattern of the immunoglobulin heavy chain genes or T-cell receptor (TCR) genes. Three cases had rearranged C mu genes but germline TCR genes, one case showed rearrangement of both C mu and TCR genes, and the remaining case had rearranged TCR genes but germline C mu genes. All five patients attained prompt remission after standard induction chemotherapy. Three to four years after initial diagnosis, four patients are now off chemotherapy and remain alive in their first remission. One patient relapsed at 3 years, 7 months, but promptly achieved complete remission after reinduction chemotherapy and remains in second remission off chemotherapy greater than 3 years after her reinduction therapy. With two-color immunofluorescence staining techniques and multiparameter flow cytometric analyses, we identified a small population of CD2+CD19+ lymphoid cells in fetal livers (FLs) and fetal bone marrows (FBMs), which may represent the putative normal counterparts of biphenotypic ALL blasts. A CD2+CD19+ normal biphenotypic lymphoid precursor cell line, designated FL 8.2 CD2+, was established from an FL of 8-weeks of gestational age by Epstein-Barr virus (EBV)-induced blastoid transformation. The composite immunophenotype of FL 8.2 CD2+ cell line was [TdT+HLA-ABC+HLA-DR+ CD2+CD5-CD7-CD10+/-CD13-CD19+CD20-CD21+ CD22+CD33-CD34+/-Bgp95-CDw40+C mu-slgD-slgM-]. FL 8.2 CD2+ cells showed germline patterns of immunoglobulin heavy-chain joining region, heavy- chain constant region, kappa light-chain constant region genes, and TCR beta-chain genes. Cross-linking of CD2 as well as CD19 antigens on FL 8.2 CD2+ cells caused an increase of intracellular ionized calcium.(ABSTRACT TRUNCATED AT 400 WORDS)     

CD2+, CD3-, CD56/NCAM+ malignant lymphoma with TCRβ gene rearrangement: A case report

A case of CD56/NCAM+ malignant lymphoma is reported. Only a rare malignant lymphoma cell showed azurophilic granules in the cytoplasm of Giesma-stained preparations, while electron microscopic examination revealed occasional cytoplasmic granules with paracrystalline inclusions. The most common phenotype seen in NK lymphomas, CD2+, CD3-, CD56+, CD16-, CD57-, was present in the case. Cases with this phenotype have been interpreted to represent either true NK lymphoma or T-cell lymphoma with NK expression. Genotyping, where performed, has shown TCR germline configuration. Our case showed TCRβ rearrangement indicating that the above phenotype can be associated with a peripheral T-cell lymphoma.     

Classification of large granular lymphocyte (LGL) and NK-associated (NKa) disorders

Literature trends indicate an increasing awareness regarding the frequency, nature and clinical associations of abnormal and persistent expansions of lymphocytes with cytoplasmic granulation. These particular cells, which represent a minor normal lymphoid subpopulation and are widely referred to as large granular lymphocytes (LGL), generally (but not invariably) express monoclonal antibody-defined membrane NK-associated (NKa) determinants and appear to functionally correspond to those populations involved in cellular cytotoxicity. Increased proportions or absolute numbers of blood lymphocytes with LGL morphology and/or NKa+ phenotypes are associated with a diverse spectrum of clinical (haematological and non-haematological) disorders and may be broadly viewed as secondary (acute and chronic reactive) or primary in nature. Both primary and secondary LGL/NKa+ expansions may be persistent in type and the clinical distinction between the two may be difficult. A number of investigators have proposed schemes for the classification of these disorders but, because of their diversity, abnormal LGL/NKa+ expansions often defy rigid compartmentalisation. This communication examines the general basis of these classifications and illustrates their limitations by reviewing the data for 97 patients recorded in the largest (Yorkshire Leukaemia Group) survey to date of persistent LGL/NKa+ expansions.     

Stages of T-cell receptor protein expression in T-cell acute lymphoblastic leukemia.

In this study five monoclonal antibodies (MoAbs) to T-cell receptor (TCR) proteins (WT31, alpha F1, beta F1, TCR delta-1 and delta TCS-1) were used to identify discrete maturative stages in 40 cases of T-cell acute lymphoblastic leukemia (T-ALL). These MoAbs reacted exclusively with CD3+ T cells and did not label B-lineage and myeloid cells. In 17 of the 40 T-ALL cases studied the leukemic blasts lacked membrane and cytoplasmic TCR chains (group I). In 12 cases cells did not have membrane CD3/TCR but expressed cytoplasmic TCR proteins heterogenously: nine cases had cytoplasmic TCR beta chains (beta F1+, alpha F1-; group II), one case had cytoplasmic TCR alpha chains (alpha F1+, beta F1-; group III), and two cases were labeled by both alpha F1 and beta F1 MoAbs (group IV). The remaining 11 cases were mCD3+: nine were TCR alpha beta+ (group Va) and two exhibited TCR gamma delta (TCR delta-1+, delta TCS-1+; group Vb). The analysis of the TCR beta, -gamma, and -delta gene configurations in 23 of the 40 T-ALLs showed that: (1) the lack of TCR protein expression was due to the lack of TCR gene rearrangements only in one of nine cases; (2) five of five TCR beta+, TCR alpha- cases studied had germline TCR alpha genes (ie, no detectable TCR delta gene deletions); (3) seven of eight cases with TCR delta gene deletions expressed TCR alpha proteins, whereas in 12 of 20 of the T-ALLs with TCR beta gene rearrangements the synthesis of the corresponding protein occurred; only 2 of 16 cases with rearranged TCR delta genes expressed TCR delta chains. The T-ALL categories identified with anti-TCR MoAbs did not have additional characteristic phenotypic patterns and may correspond to the normal stages of T-cell development more precisely than those defined by other differentiation antigens.     

Clonal populations of CD4+ and CD8+ T cells in patients with multiple myeloma and paraproteinemia

Patients with paraproteinemia have abnormalities in their T-cell subsets including inversion of the CD4:CD8 ratio and increased expression of activation markers. Recently, distortions in T-cell receptor (TCR) TCRAV and TCRBV gene segment expression have been reported, although the significance of these observations is unclear given the finding of clonal populations of CD8+ T cells in healthy elderly individuals. We have used an extensive range of TCR V-region- specific monoclonal antibodies to assess TCRAV and TCRBV expression in patients with myeloma and paraproteinemia. TCR sequence analysis was used to assess the clonality of expansions and 3-color fluorescence- activated cell sorting analysis determined the phenotype of the expanded populations. The patients show novel oligoclonal expansions within the CD4+ subset and show an increased frequency of CD8+ expansions. Oligoclonal CD4+ T cells belong to the rare CD4+CD28- T- cell subset, a phenotype associated with granular morphology. CD45RA and CD11b are expressed on many of the CD8 T-cell expansions. Comparison of T-cell receptor sequences from two T-cell clones in one patient suggests a possible role for a common peptide antigen in the generation of the expansions. Further work is needed to identify the relevance of such T cells to the B-cell proliferation.     

CD5-CD56+ T-cell receptor silent peripheral T-cell lymphomas are natural killer cell lymphomas [see comments]

Non-Hodgkin's lymphomas are divided into B- and T-cell neoplasms. The existence and the clinical relevance of lymphomas derived from the third lymphocyte lineage, ie, natural killer (NK) cells are still controversial. NK cells are lymphocytes that mediate cytotoxicity without prior sensitization. NK cells also have phenotypic and genotypic characteristics: they express the NK-related antigen CD56, T- cell markers such as CD2 and CD7, but do not express CD5 and T-cell receptor (TCR) proteins, and their TCR locus is not rearranged. Therefore, if NK cell lymphomas exist, they should express some T-cell markers, but not alpha beta or gamma delta TCR proteins. Such lymphomas are actually called TCR silent peripheral T cell lymphomas (PTCL). To detect and characterize NK cell lymphomas, we investigated the immunophenotype and immunogenotype of 35 patients with TCR silent PTCL. The first group included 16 patients with a lymphoma of CD5-CD56+ phenotype, which is identical to normal NK cells. These patients had either a nasal/nasopharyngeal lymphoma (11 cases) or a lymphoma with predominant non-nasal/non-nodal initial involvement (five cases). Eight of the nine cases for which immunogenotypic data were available lacked clonal rearrangement of the TCR gamma genes. Thus, these tumors are likely to be NK cell lymphomas. The second group of 15 cases had a CD5+ phenotype (14 were CD56-, and 1 was CD56+) and clonal rearrangement of TCR gamma genes, indicating that they were true PTCL with unproductive TCR rearrangement. The four remaining cases were CD5- CD56- lymphomas and disclosed either a clonal (two cases) or no clonal (two cases) rearrangements of the TCR gamma genes. Altogether these findings show that CD5-CD56+ so-called "TCR silent PTCL" bear the immunophenotype and immunogenotype of normal NK cells and display peculiar clinical features distinct from true PTCL.     

Lineage determination of CD7+ CD5− CD2− and CD7+ CD5+ CD2− lymphoblasts: Studies on phenotype,genotype, and gene expression of myeloperoxidase,CD3ϵ, and CD3δ

The gene expression of myeloperoxldase (MPO), CD3? and CD3δ molecules, the gene rearrangement of T-cell receptor (TCR)δ, γ, and β and Immunoglobulin heavy (IgH) chain, and the expression of cell-surface antlgens were investigated In seven cases of CD7+ CD5? CD2? and four cases of CD7+ CD5+ CD2? acute lymphoblastic leukemia or lymphoblastic lymphoma (ALL/LBL) blasts, which were negative for cytochemical myeloperoxidase (cyMPO). More mature T-lineage blasts were also investigated in a comparative manner. In conclusion, the CD7+ CD5? CD2? blasts included four categories: Undifferentiated blasts without lineage commitment, T-lineage blasts, T-/myeloid lineage blasts, and cyMPO-negative myeioblasts. The CD7+ CD5+ CD2? blasts included two categories; T-lineage and T-/myeloid lineage blasts. The 11 cases were of the germ-line gene (G) for TCRβ and IgH. Four cases were G for TCRδ and TCRγ. The others were of the monoclonally rearranged gene (R) for TCRδ and G for TCRγ or R for both TCRδ and TCRγ. The expression or In vitro induction of CD13 and/or CD33 antigens correlated with the immaturity of these neoplastic T cells, since it was observed In all 11 CD7+ CD5? CD2?and CD7+ CD5+ CD2?, and some CD7+ CD5+ CD2+ (CD3? CD4? COB-) cases, but not in CD3± CD4+ CD8+ or CD3+ CD4+ CD8? cases. CD3? mRNA, but not CD3δ mRNA, was detected in two CD7+ CD5? CD2? cases, while mRNA of neither of the two CD3 moleculea was detected In the other tested CD7+ CD5?CD2? cases. In contrast, mRNA of both CD3e and CD36 were detected in ail CD7+ CD5+ CD2? cases, indicating that CD7+ CD5+ CD2? blasts at least belong to T-lineage. The blasts of two CD7+ CD5? CD2? cases with entire germ-line genes and without mRNA of the three molecules (MPO, CD3?, and CD3δ) were regarded as being at an undifferentiated stage prior to their commitment to either T- or myelold-lineage. The co-expression of the genes of MPO and CD3e In a CD7+ CD5? CD2? case or MPO, CD3?, and CD3δ in a CD7+ CD5+ CD2? case suggested the presence of some overlapping phase for T- and myeloid-lineage commitment during Immature stages of differentiation. This heips understand the conversion of some T-ALL/LBL cases to acute myeloblastic leukemia (AML). The detection of CD3?, but not CD3δ mRNA, in two CD7+ CD5? CD2?cases indicated that the gene expression of CD3? occurs at a more immature stage of differentiation than that of the CD3δ chain. © 1994 Wiley-Liss, Inc.     

T-cell receptor variable region gene usage by CD4+ and CD8+ T cells in bronchoalveolar lavage fluid and peripheral blood of sarcoidosis patients.

Sarcoidosis is a chronic noncaseating granulomatous disease of unknown etiology. An accumulation of CD4+ T cells in the alveolar space of the lungs is a characteristic feature of the disease. We have in this study analyzed T-cell receptor (TCR) variable region (V) gene usage by CD4+ and CD8+ lung and peripheral blood T cells of 29 sarcoidosis patients and 15 control subjects. In the patient group, we found a 100% positive correlation between TCR V alpha 2.3+ CD4+ lung T-cell expansions and the expression of the HLA-DR3(17),DQ2 haplotype. The remaining TCR V alpha/V beta gene products analyzed in this study--V alpha 12, V beta 2, V beta 3, V beta 5.1, V beta 5.2/5.3, V beta 5.3, V beta 6.7, V beta 8.1, and V beta 12--were in general normally expressed by CD4+ T cells, although some of them were used to a significantly higher or lower degree by lung T cells compared to peripheral blood T cells. We also performed repeated TCR V gene analyses on some HLA-DR3+ patients and found an association between the ratio bronchoalveolar lavage fluid/peripheral blood V alpha 2.3+ CD4+ T cells and clinical signs of disease activity. Finally, when analyzing TCR V gene usage by CD8+ bronchoalveolar lavage fluid and peripheral blood T cells, a normal V alpha 2.3 usage was found in all cases, but lung-restricted T-cell expansions using other TCR V gene segment products were identified.     

CD56+CD7+ stem cell leukemia/lymphoma with D2-Jdelta1 rearrangement.

OBJECT: We describe the characteristics of three patients with CD56+CD7+ stem cell leukemia/lymphoma. METHODS: These blasts were analyzed for morphologic, karyotypic, immunophenotypic, and immunogenotypic features using Southern blot and polymerase chain reaction analysis. MATERIALS: Peripheral blood, bone marrow aspirates, or biopsied mediastinal tumor specimens of three CD56+CD7+ stem cell leukemia/lymphoma patients were investigated. RESULTS: The bone marrow of all patients showed myeloperoxidase (MPO) negative blast cells with basophilic cytoplasm and distinct nucleoli with no azurophilic granules. The blasts of two patients were classified as acute lymphoblastic leukemia (L2). The liver, spleen, and lymph nodes were unaffected in all patients. All had an aggressive clinical course. The blasts were strongly positive for both CD7 and CD56 but negative for other T-lineage associated antigens, including CD1, CD2, surface membrane CD3, cytoplasmic CD3c (2/2), CD4, CD5 and CD8. The additional antigens were recognized as follows: CD19 (1/3 cases) as a B lineage, CD33 (1/3) as a myeloid marker, CD34 (2/3) as a stem cell, CD38 (1/1) and HLA-DR (2/3). When the patients relapsed, the phenotypes changed to blasts positive for CD5, CD10 and CD13 in patient 1, CD5 in patient 2, and CD33 in patient 3. MPO, however, remained negative. Cytogenetic analysis showed no common abnormal karyotype. All had a common D2-Jdelta1 induced by T-cell specific enhancer. Rearrangement of TCR beta and gamma genes occurred in patient 2, and IgH and TCR beta underwent rearrangement in patient 3. CONCLUSION: Although a more comprehensive case analysis is necessary, these data suggest the possibility that the blasts of the present cases come from a common lymphoid precursor (T, NK, and B cell) or from a NKT precursor as the fourth lymphoid lineage.     

慢性乙型肝炎患者CD3+CD56+淋巴细胞及其表型与病情的关系

目的 探讨CD3+CD56+淋巴细胞与慢性乙型肝炎(CHB)患者病情变化和转归的关系.方法 CHB患者53例,HBV携带者17例,19名健康体检者为对照组.研究对象均抽取外周血2～3ml,采用流式细胞技术测定CD3+CD56+淋巴细胞,并进一步分析CD3+CD56+淋巴细胞表面CD4,CD8、T细胞抗原受体(TCR)V α 24,TCR α/β以及TCR γ/δ的表达.结果CHB组CD3+CD56+淋巴细胞为7.4%±4.6%,慢性HBV携带者组为4.5%±3.5%,对照组为4.4%±3.7%,CHB组CD3+CD56+淋巴细胞明显升高.3组人群CD3+CD56+淋巴细胞TCR V α 24的表达,差异无统计学意义.慢性HBV携带者组CD3 CD56+细胞表达的TCR V α 24为2.8%±1.4%,明显高于对照组1.7%±1.0%.CHB组CD3+CD56+细胞CD8和TCRα/β的表达分别为61.9%±16.8%和68.1%±16.9%,对照组为49.2%±15.6%和56.4%±17.9%,CHB组均明显高于对照组.CHB组和HBV携带者组TCR γ/δ的表达,分别为29.6%±15.4%和30.5%±14.8%,CHB组和HBV携带者明显低于对照组41.4%±19.4%.CHB重度患者CD3+CD56 1细胞CD8和TCR α/β的表达分别为69.0%±14.0%和76.1%±12.9%,CHB中度患者CD8的表达为66.4%±14.9%,均明显高于CHB轻度患者51.4%±16.2%和62.1%±14.6%. 结论 慢性乙型肝炎的活动可能与CD3+CD56+淋巴细胞的CD8高表达有关.     

Expansion of pulmonary CD8+CD56+ natural killer T-cells in hypersensitivity pneumonitis

BACKGROUND: Natural killer T (NKT) cells, a newly identified subgroup of T cells with immunoregulatory function, may be implicated in the pathogenesis of interstitial lung disease (ILD). METHODS: We used multiparameter flow cytometry with antibodies to CD3, CD4, CD8, CD14, CD19, CD45, CD16/56, CD56, CD161, and Valpha24 invariant T-cell receptor (TCR) in BAL fluid (BALF) to examine the frequency and distribution of pulmonary NKT cells in several cases of ILD. We included 57 patients with sarcoidosis and 17 patients with hypersensitivity pneumonitis. RESULTS: We found significantly higher frequencies of pulmonary NKT cells in patients with hypersensitivity pneumonitis in comparison to the other study patients with ILD (median proportion of NKT cells, 11%; range, 3 to 38%; vs 3%; range, 0 to 16%; p < 0.0001). In contrast, there was no difference in the proportion of conventional natural killer cells. We found that a major subset of NKT cells in the BALF of patients with hypersensitivity pneumonitis was a CD8+CD56+ population that did not express the invariant TCR. CONCLUSIONS: These results suggest the involvement of NKT cells in the pathogenesis of hypersensitivity pneumonitis.     

Establishment of an IL-2-dependent cell line derived from 'nasal-type' NK/T-cell lymphoma of CD2+, sCD3−, CD3ɛ+, CD56+ phenotype and associated with the Epstein-Barr virus

A novel interleukin-2 (IL-2)-dependent cell line, HANK1, was established from a patient with CD56⁺ NK/T-cell lymphoma arising in the retroperitoneum. Morphologically, HANK1 is a pleomorphic large cell line with irregular nuclei, which contains azurophilic granules in the cytoplasm. Immunophenotypic analysis showed that HANK1 expressed CD2, CD3ɛ, CD56, TIA-1, granzyme B, and HLA-DR, but no other T-lineage markers. These features were the same as seen in the original tumour, and are highly characteristic of nasal and 'nasal-type' NK/T-cell lymphoma as described in the proposed W.H.O. classification. Genotypically, this cell line also demonstrated the germline configuration of the T-cell receptor β, γ and the immunoglobulin heavy chain genes and clonal integration of the Epstein-Barr virus (EBV) together with antigen expression with a type II latency pattern (LMP-1⁺ and EBNA2⁻). Furthermore, Southern blot analysis using the EBV termini as probes confirmed its derivation from the original lymphoma, and revealed that it contained multiple copies of the EBV genome. Dose-dependent growth on IL-2 was observed in an in vitro study with a doubling time of 3 d at maximal stimulation. These data indicate that HANK1 seemed to preserve the biological characteristics of the original tumour and therefore may serve as a good model for the further analysis of unusual 'nasal-type' NK/T-cell lymphoma.     

CD3+ CD8+ CD56− clonal large granular lymphocyte leukaemia and HIV infection

High-grade malignant lymphomas associated with HIV infection are usually derived from B lymphocytes. Although a broad spectrum of T-cell-derived malignancies has been described, no case of monoclonal T large granular lymphocyte leukaemia has been reported to date. We report a case of clonal T-LGL (CD3⁺, CD4⁻, CD8⁺, CD56⁻, CD57⁺) in an HIV-infected, HTLV1/2-negative individual. Large granular lymphocytes are thought to represent activated cytotoxic T lymphocytes. HIV infection, as previously reported for HTLV1/2, may represent a pathway of antigen activation and lead to clonal expansion of T large granular lymphocytes.     

CD3−CD4−CD8−CD56−CD19−CD14− cells and CD3+CD8 dull-positive cells produce IL-4 in AIDS patients

We used flow cytometry to identify the presence of intracellular cytokines (cytoflow) and analyse the production of IL-4 in peripheral blood from AIDS patients who have practically no CD4⁺ T cells. We found that IL-4 was produced by CD3⁻CD4⁻CD8⁻CD56⁻CD19⁻CD14⁻ cells and CD3⁺CD8 dull-positive cells in AIDS patients. Moreover, CD3⁻CD4⁻ CD8⁻CD56⁻CD19⁻CD14⁻ cells had helper activity for immunoglobulin synthesis. These findings indicate that instead of CD4⁺ T helper cells, C3⁻CD4⁻CD8⁻CD56⁻ CD19⁻CD14⁻ cells and CD3⁺CD8 dull-positive cells may be an important source of IL-4 in a variety of immune responses for AIDS patients.