Genotype, phenotype and hormonal levels correlation in non-classical congenital adrenal hyperplasia

Non-classical congenital adrenal hyperplasia (NCAH) is a morbid condition sustained by the reduced function of one of the enzymes involved in the adrenal steroid biosynthesis pathway, mainly the 21-hydroxylase. Different degrees of enzyme activity impairment determine different clinical pictures, with childhood or post-pubertal onset. The aim of this study was to evaluate the relationship between genotype, phenotype, and adrenal hormonal levels in a group of 66 patients affected by NCAH attending outpatient pediatric or endocrinological Clinics. Our findings show that age at pubarche/menarche was significantly younger, height SD score) and Δ bone age-chronological age were significantly higher in patients with a more severe enzyme activity impairment, while cutaneous androgenization and menstrual irregularities in post-pubertal girls were not related to the grading of genotype.

A family with autosomal dominant leukodystrophy linked to 5q23.2-q23.3 without lamin B1 mutations

BACKGROUND AND PURPOSE

Duplications of lamin B1 (LMNB1) at 5q23 are implicated in adult-onset autosomal dominant leukodystrophy (ADLD) having been described in six families with diverse ethnic background but with a homogeneous phenotype. In a large Italian family, we recently identified a variant form of ADLD characterized clinically by absence of the autonomic dysfunction at onset described in ADLD and, on MRI, by milder cerebellar involvement with sparing of hemispheric white matter. Aim of this study was to investigate the genetic basis of this variant form of ADLD.

METHODS

We carried out a genome-wide linkage analysis using microsatellite markers, and the genes in the candidate region were screened for point mutations. LMNB1 was also screened for deletions/duplications by real-time PCR, multiplex ligation-dependent probe amplification and Southern blot.

RESULTS

We mapped the variant ADLD locus to 5q23.2-q23.3, a genomic region containing 11 genes including LMNB1. Neither gene copy-number defects nor point mutations in the LMNB1 gene were found. We also excluded point mutations in the coding exons of the other ten genes in the candidate region. However, expression of lamin B1 evaluated in lymphoblastoid cells was higher in patients than in healthy controls, and was similar to the lamin B1 expression levels found in a patient with LMNB1 duplication.

CONCLUSIONS

This observation suggests that a mutation in an LMNB1 regulatory sequence underlies the variant ADLD phenotype. Thus, adult forms of ADLD linked to 5q23 appear to be more heterogeneous clinically and genetically than previously thought.

Mutations in the lamin B1 gene are not present in multiple sclerosis

BACKGROUND

Whole gene duplication of the lamin B1 gene (LMNB1), encoding for a protein of the nuclear lamina, causes an adult-onset autosomal dominant leukodystrophy (ADLD). Clinical features of ADLD (onset in adult life, dysautonomic symptoms, followed by pyramidal and cerebellar dysfunctions) partially resemble those of multiple sclerosis (MS), particularly the primary-progressive form. Our aim was to test whether LMNB1 gene mutations were present amongst patients with a diagnosis of MS.

METHODS

One hundred eighty-two MS patients were screened for copy number variations of the LMNB1 gene using a qPCR assay. Point mutations in the LMNB1 gene were searched by denaturing high-performance liquid chromatography and direct sequencing in a subgroup of 16 patients with familial MS.

RESULTS

No duplication/deletion of the lamin B1 gene was found amongst MS patients, and no point mutation was identified in the familial cases.

CONCLUSION

Our work indicates that lamin B1 defects are probably not responsible for signs and symptoms resembling multiple sclerosis.

A novel family with Lamin B1 duplication associated with adult-onset leucoencephalopathy

BACKGROUND AND AIMS

Duplication of the lamin B1 gene (LMNB1) has recently been described in a rare form of autosomal dominant adult-onset leucoencephalopathy. The aim of the study was to evaluate the presence of LMNB1 gene defects in a series of eight patients with diffuse adult-onset hereditary leucoencephalopathy.

METHODS

Clinical features of tested patients included a variable combination of pyramidal, cerebellar, cognitive and autonomic dysfunction. Neuroradiological data (MRI) showed symmetrical and diffuse white-matter lesions in six cases, and multifocal confluent lesions in two. LMNB1 full gene deletion/duplication and point mutations were searched using a TaqMan real-time PCR assay and direct sequencing of all coding exons.

RESULTS

One patient carried a 140-190 kb duplication involving the entire LMNB1 gene, the AX748201 transcript and the 3' end of the MARCH3 gene. Clinical and neuroimaging data of this proband and an affected relative overlapped with the features already described in patients with LMNB1 duplication. Lamin B1 expression was found increased in lymphoblasts. No LMNB1 gene defect was identified in the remaining seven probands.

CONCLUSIONS

LMNB1 gene duplication appears characteristic of a subset of adult-onset autosomal dominant leucoencephalopathies, sharing autonomic dysfunction at onset, diffuse T2-hyperintensity of supra- and infratentorial white matter, sparing of U-fibres and optic radiations. The variable phenotypes in the remaining cases lacking LMNB1 defects (five with autosomal dominant transmission) suggest that adult-onset leucoencephalopathies are genetically heterogeneous.

The polymorphic polyglutamine repeat in the mitochondrial DNA polymerase gamma gene is not associated with oligozoospermia

The POLG1 nuclear gene, encoding for the catalytic subunit of the mitochondrial polymerase gamma, has been reported to play a role in male infertility. In fact, genotypes showing alleles different from the common ten repeat CAG allele have been detected in patients with oligozoospermia or in patients with normal spermiograms and unexplained infertility. However, these results have been debated by other studies. To verify these data, we analyzed 625 individuals in three groups of case-controls from three different Italian regions. In these series, the frequency of the different genotypes was not statistically different in oligozoospermic vs normal subjects. Even considering the pooled controls and patients (348 and 277, respectively), no significant difference was shown (p = 0.11). Our findings, in agreement with other studies from Italy and France, suggest that, at least in these countries, the POLG1 CAG-repeat polymorphisms do not contribute to oligozoospermia.

Camurati-Engelmann disease: review of the clinical, radiological, and molecular data of 24 families and implications for diagnosis and treatment

Camurati-Engelmann disease (CED) is a rare autosomal dominant type of bone dysplasia. This review is based on the unpublished and detailed clinical, radiological, and molecular findings in 14 CED families, comprising 41 patients, combined with data from 10 other previously reported CED families. For all 100 cases, molecular evidence for CED was available, as a mutation was detected in TGFB1, the gene encoding transforming growth factor (TGF) beta1. Pain in the extremities was the most common clinical symptom, present in 68% of the patients. A waddling gait (48%), easy fatigability (44%), and muscle weakness (39%) were other important features. Radiological symptoms were not fully penetrant, with 94% of the patients showing the typical long bone involvement. A large percentage of the patients also showed involvement of the skull (54%) and pelvis (63%). The review provides an overview of possible treatments, diagnostic guidelines, and considerations for prenatal testing. The detailed description of such a large set of CED patients will be of value in establishing the correct diagnosis, genetic counselling, and treatment.

FMR1 gene premutation is a frequent genetic cause of late-onset sporadic cerebellar ataxia

In an Italian population of 275 unrelated men affected by adult-onset sporadic progressive cerebellar ataxia, the authors found six patients carrying an FMR1 gene premutation. Age at onset (range, 53 to 69 years) and clinical-neuropathologic findings were consistent with the fragile-X tremor ataxia syndrome (FXTAS), although tremor was not as common as previously described. FXTAS accounted for 4.2% of the cases diagnosed at >50 years, suggesting that it is a frequent genetic cause of late-onset sporadic ataxia.

TSC1 and TSC2 deletions differ in size, preference for recombinatorial sequences, and location within the gene

Large TSC gene rearrangements are not rare findings in tuberous sclerosis. Interestingly, all deletions, duplications and inversions so far described involve TSC2, none being associated with TSC1. In order to shed light on the structural basis of the preferential DNA rearrangements in TSC2 over TSC1 and to assess, in an unselected patient population, the prevalence of large re-arrangements in both TSC loci, we screened 202 tuberous sclerosis patients consecutively referred at our center. Southern blot analysis on EcoRI+HindIII double-digested DNA identified 19 partial or full-length gene deletions: three involved TSC1 and sixteen TSC2. The breakpoint sequence of seven internal deletions, three in TSC1 and four in TSC2, allowed us to speculate on the mechanism favoring TSC2 unequal recombinations and to identify a deletion hot spot that lies in TSC1 and that may be relevant in the routine genetic testing of tuberous sclerosis. Briefly, three major features appear to distinguish TSC1 from TSC2 deletions: (1) deletion size: all TSC1 deletions are within the transcriptional unit, whereas 12 of the 16 TSC2 deletions have at least one external breakpoint; (2) location within the gene: all TSC1 deletions are confined to the 3'end of the gene (all three 5' breakpoints being located in intron 20) thus resulting in the same frameshift mutation following amino acid K875, whereas the TSC2 internal breakpoints appear to be scattered along the gene; (3) preference for recombinatorial sequences: six out of eight internal TSC2 breakpoints map within Alu repeats, whereas none of the three TSC1 deletions appear to be Alu-mediated. Indeed, in the latter gene, unique structural features (a purine-rich tract flanked by pyrimidine-rich segments) surrounding one of the two identified breakpoint cluster regions might play a role in promoting inappropriate recombinations.

Mutations in the gene encoding the latency-associated peptide of TGF-beta 1 cause Camurati-Engelmann disease

Camurati-Engelmann disease (CED; MIM 131300), or progressive diaphyseal dysplasia, is a rare, sclerosing bone dysplasia inherited in an autosomal dominant manner. Recently, the gene causing CED has been assigned to the chromosomal region 19q13 (refs 1-3). Because this region contains the gene encoding transforming growth factor-beta 1 (TGFB1), an important mediator of bone remodelling, we evaluated TGFB1 as a candidate gene for causing CED.

Localisation of the gene causing diaphyseal dysplasia Camurati-Engelmann to chromosome 19q13

Camurati-Engelmann disease, progressive diaphyseal dysplasia, or diaphyseal dysplasia Camurati-Engelmann is a rare, autosomal dominantly inherited bone disease, characterised by progressive cortical expansion and sclerosis mainly affecting the diaphyses of the long bones associated with cranial hyperostosis. The main clinical features are severe pain in the legs, muscular weakness, and a waddling gait. The underlying cause of this condition remains unknown. In order to localise the disease causing gene, we performed a linkage study in a large Jewish-Iraqi family with 18 affected subjects in four generations. A genome wide search with highly polymorphic markers showed linkage with several markers at chromosome 19q13. A maximum lod score of 4.9 (theta=0) was obtained with markers D19S425 (58.7 cM, 19q13.1) and D19S900 (67.1 cM, 19q13. 2). The disease causing gene is located in a candidate region of approximately 32 cM, flanked by markers D19S868 (55.9 cM, 19q13.1) and D19S571 (87.7 cM, 19q13.4).

The SH3 domains of endophilin and amphiphysin bind to the proline-rich region of synaptojanin 1 at distinct sites that display an unconventional binding specificity

The proline-rich domain of synaptojanin 1, a synaptic protein with phosphatidylinositol phosphatase activity, binds to amphiphysin and to a family of recently discovered proteins known as the SH3p4/8/13, the SH3-GL, or the endophilin family. These interactions are mediated by SH3 domains and are believed to play a regulatory role in synaptic vesicle recycling. We have precisely mapped the target peptides on human synaptojanin that are recognized by the SH3 domains of endophilins and amphiphysin and proven that they are distinct. By a combination of different approaches, selection of phage displayed peptide libraries, substitution analyses of peptides synthesized on cellulose membranes, and a peptide scan spanning a 252-residue long synaptojanin fragment, we have concluded that amphiphysin binds to two sites, PIRPSR and PTIPPR, whereas endophilin has a distinct preferred binding site, PKRPPPPR. The comparison of the results obtained by phage display and substitution analysis permitted the identification of proline and arginine at positions 4 and 6 in the PIRPSR and PTIPPR target sequence as the major determinants of the recognition specificity mediated by the SH3 domain of amphiphysin 1. More complex is the structural rationalization of the preferred endophilin ligands where SH3 binding cannot be easily interpreted in the framework of the "classical" type I or type II SH3 binding models. Our results suggest that the binding repertoire of SH3 domains may be more complex than originally predicted.

Polycystin-1 expression in PKD1, early-onset PKD1, and TSC2/PKD1 cystic tissue

BACKGROUND

The mutational mechanism responsible for cyst formation in polycystic kidney disease 1 gene (PKD1) remains controversial, with data indicating a two-hit mechanism, but also evidence of polycystin-1 expression in cystic tissue.

METHODS

To investigate this apparent paradox, we analyzed polycystin-1 expression in cystic renal or liver tissue from 10 patients with truncating PKD1 mutations (including one early-onset case) and 2 patients with severe disease associated with contiguous deletions of TSC2 and PKD1, using monoclonal antibodies (mAbs) to both extreme N-(7e12) and C-terminal (PKS-A) regions of the protein. Truncation of the C-terminal epitope from the putative mutant proteins in each case allowed exclusive assessment of the nontruncated protein with PKS-A.

RESULTS

In adult PKD1 tissue, the majority of cysts (approximately 80%) showed polycystin-1 expression, although staining was absent in a variable but significant minority (approximately 20%), in spite of the normal expression of marker proteins. Unlike adult PKD1, however, negative cysts were rarely found in infantile PKD1 or TSC2/PKD1 deletion cases.

CONCLUSIONS

If a two-hit mutational mechanism is operational, these results suggest that the majority of somatic mutations in adult PKD1 are likely to be missense changes. The low level of polycystin-1-negative cysts in the three "early-onset" cases, however, suggests that a somatic PKD1 mutation may not always be required for cyst formation.

A large TSC2 and PKD1 gene deletion is associated with renal and extrarenal signs of autosomal dominant polycystic kidney disease

BACKGROUND

The renal lesions in tuberous sclerosis complex (TSC) consist in multiple angiomyolipomas, often associated with cysts of variable size. Recently a few TSC patients with early-onset renal cysts resembling the autosomal dominant polycystic kidney disease (ADPKD) have been described. Virtually all of them showed deletions of both TSC2 and PKD1 genes.

METHODS

Two unrelated families in which TSC and PKD co-segregate were investigate. 16p13.3-linked haplotype segregation, Southern blot, pulsed field gel electrophoresis, and loss of heterozygosity analyses were performed in both affected and unaffected family members.

RESULTS

The proband from family 1 was first recognized as presenting typical neurological signs and skin lesions of TSC and multiple renal cysts at 12 years of age. Haemodialysis became necessary at age 28. CT and MRI scans revealed multiple cysts in the live and an asymptomatic, 3-4 mm aneurysm of the middle cerebral artery. His mother, who died at 47 of breast cancer, had ADPKD and reached the ESRD at 42. She showed facial angiofibromas. Both patients carried a submicroscopic germline deletion spanning the entire TSC2 gene and the large majority of PKD1 coding sequence. In the proband from family 2, the TSC diagnosis was made at 4 years. Enlarged polycystic kidneys causing and-stage renal failure at 19 years were observed. This patient carried a large germline, de novo deletion involving the entire TSC2 and PKD1 genes. In addition we could show in a renal hamartoma from this subject the loss of heterozygosity of markers spanning the TSC2 and PKD1 genes from the residual, normal chromosome 16 of paternal origin.

CONCLUSIONS

The presence of a deletion involving both TSC2 and PKD1 genes should be considered in the clinical assessment of TSC children with an early-onset polycystic kidney disease, and more generally in all ADPKD patients who develop end-stage renal failure prior to the fourth or fifth decade of life. Finally, the occurrence of typical renal and extrarenal signs of ADPKD in a PKD1 hemizygote individual seems to support concept that a somatic inactivation of the residual PKD1 gene is required for the development of the cysts.

A novel SH3-containing human gene family preferentially expressed in the central nervous system

The Src-homology-3 domain (SH3) is an evolutionarily conserved, 50- to 60-amino-acid module carried by intracellular proteins involved in the transduction of signals for cell polarization, motility, enzymatic activation, and transcriptional regulation. The SH3 drives protein-protein interactions through binding to proline-rich ligands. This function relies on the conserved secondary structure, whereas the SH3 primary structure is highly diverse. Taking advantage of the fact that the few conserved amino acids are clustered near the N- and C-terminal ends, we designed degenerate oligonucleotides spanning these two regions and screened by PCR a variety of normal and tumor tissues for the expression of SH3-containing transcripts. Using this strategy, we have identified a novel SH3-containing human gene family of six related transcripts that map to four different chromosomes. The SH3 domain lies at the C-terminal end and shows 56-50% amino acid homology to the C-terminal SH3 of Sem-5/Drk/GRB2. The N-terminal segment of this novel SH3GL (from SH3-containing Grb2-like) gene family does not resemble any known protein. Three of these transcripts are in-frame and show a peculiar tissue distribution: SH3GL2 is preferentially expressed in the brain, SH3GL3 in brain and testis, and SH3GL1 is ubiquitous.

Tuberous sclerosis complex: neonatal deaths in three of four children of consanguineous, non-expressing parents

We describe here four sibs, born to consanguineous, healthy, asymptomatic parents. Three of these infants had a rapidly fatal course in the neonatal period; death was attributed to congestive heart failure with radiographic evidence of cardiomegaly in all of them. Necropsy was done in only one of them and showed the typical findings of tuberous sclerosis complex (TSC) in the central nervous system (CNS), kidneys, heart, and liver. The fourth sib, currently 2 years old, also has typical signs of TSC, namely hypomelanotic skin macules and calcified subependymal nodules. Both parents and a living maternal grandmother had appropriate examination, which included skin inspection under Wood's lamp, dental examination, fundoscopy, echocardiography, abdominal and renal ultrasound, and head CT and MRI scans, and no signs of TSC were found in either parent or in the only living grandmother. By history alone there is no other relative with signs or symptoms suggestive of TSC. Linkage analysis and loss of heterozygosity (LOH) investigations on a variety of lesions obtained from postmortem and tissue or blood specimens from all available family members studied failed to identify a microdeletion in the chromosomal regions where TSC genes are located. It is very unusual that in a single TSC family there were three consecutive neonatal deaths, and very likely that all had cardiac rhabdomyomas. Moreover, to the best of our knowledge, there are no previous reports of TSC families with more than one affected sib, unusually severe manifestations of the disease, and completely normal, consanguineous parents.

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.

Restriction of the T-cell receptor V delta gene repertoire is due to preferential rearrangement and is independent of antigen selection

To determine whether the limited V gene usage by the T-cell receptor delta (TCRD) chain is dictated by preferential rearrangement or by antigen selection, we characterized and compared the TCRDV gene repertoire of the productive with that of the unproductive allele in 80 human TCRG/TCRD clones. Six different V genes were found on the expressed allele; two of them, provisionally named DV7 and DV8, have not been described before on the surface of TCRG/TCRD T cells. Overall, six V genes and six non-V elements were isolated from the unproductive allele. Interestingly, the same set of genes was rearranged both in the productive and in the unproductive chromosome. These findings seem to suggest that antigen-independent mechanisms play a major role in the restriction of the TCRDV gene repertoire.

9q34 loss of heterozygosity in a tuberous sclerosis astrocytoma suggests a growth suppressor-like activity also for the TSC1 gene

Tuberous sclerosis is an autosomal dominant disease whose characteristic feature is the development of multiple hamartomas in a variety of organs and tissues. Two major loci have been identified so far: TSC1 on chromosome 9q34 and TSC2 on chromosome 16p13.3. Loss of heterozygosity at 16p13.3-associated markers has been recently observed in hamartomatous lesions of some tuberous sclerosis patients. Here we report the first evidence of loss of heterozygosity at the TSC1 critical region in a giant cell astrocytoma of a familial tuberous sclerosis case. Segregation analysis showed that the 9q34 haplotype lost carried the putative normal TSC1 gene. These data support the hypothesis of both a germline and somatic loss-of-function mutation for the development of tuberous sclerosis hamartomas and suggest a tumor-suppressor-like activity also for the TSC1 gene product. Finally, the possible significance of a second small region of loss of heterozygosity at 9p21, found in the same astrocytoma, is discussed.

T cell receptor V delta 2-C alpha transcripts are present in the thymus but virtually absent in the periphery

To investigate whether the V delta 2-(D)-J alpha gene configuration, characteristically associated with the major subset of acute lymphoblastic leukemias in humans, might have a physiologic role in T cell ontogeny, we have looked for V delta 2-C alpha transcripts in the thymus and peripheral blood of normal donors. Here we show by PCR analysis that these transcripts are virtually absent in the PBMC, whereas they are present in fetal and postnatal thymus. Interestingly, over 80% of 43 V delta 2-C alpha cDNAs randomly isolated from one postnatal thymus appeared to maintain an open reading frame. This suggests that in the thymus the V delta 2-C alpha products might be exposed to selective pressure. Furthermore, in two of three thymuses tested for J alpha usage, it was found overrepresented in a J alpha element (J alpha 58) located 2 kb downstream to a pseudo-J (J alpha 61), known to be a hot spot of recombination in alpha beta committed cells. A possible alternative pathway to alpha beta T cell differentiation via a V delta 2-J alpha intermediate is discussed.

T cell receptor V delta 2-C alpha transcripts are present in the thymus but virtually absent in the periphery

To investigate whether the V delta 2-(D)-J alpha gene configuration, characteristically associated with the major subset of acute lymphoblastic leukemias in humans, might have a physiologic role in T cell ontogeny, we have looked for V delta 2-C alpha transcripts in the thymus and peripheral blood of normal donors. Here we show by PCR analysis that these transcripts are virtually absent in the PBMC, whereas they are present in fetal and postnatal thymus. Interestingly, over 80% of 43 V delta 2-C alpha cDNAs randomly isolated from one postnatal thymus appeared to maintain an open reading frame. This suggests that in the thymus the V delta 2-C alpha products might be exposed to selective pressure. Furthermore, in two of three thymuses tested for J alpha usage, it was found overrepresented in a J alpha element (J alpha 58) located 2 kb downstream to a pseudo-J (J alpha 61), known to be a hot spot of recombination in alpha beta committed cells. A possible alternative pathway to alpha beta T cell differentiation via a V delta 2-J alpha intermediate is discussed.

An alternative approach to the assessment of gamma delta T-cell clonality in celiac disease intestinal lesions through cDNA heteroduplex analysis of T-cell receptor VJ junctions

We have investigated the clonality of the gamma delta T lymphocytes infiltrating the intestinal mucosa of CD patients and control subjects by means of a simple and powerful method based on the heteroduplex analysis of the TCR VJ junctions. Each V-specific TCR chain, amplified either from fresh biopsy material or intestinal T-cell-line cDNA, is denatured and renatured to allow the random reshuffling of the various strands carrying different junctional sequences, coamplified in the same reaction. The mismatched chains (heteroduplexes) are separated from the matched ones (homoduplexes) through polyacrylamide gel electrophoresis, and whenever one or more T-cell clones are emerging over the polyclonal background, discrete bands are visible by ethidium-bromide staining. Through this method, we have estimated the diversity of the V delta 1-3 chains and a newly described V gene (V delta 8) whose homologue in mice is abundantly expressed in gamma delta iLs. We demonstrate that the well-documented expansion of V gamma 1+ gamma delta lymphocytes in the jejunum of CD patients is polyclonal. Overall, the heteroduplex analysis on fresh intestinal and peripheral blood lymphocytes from both healthy and affected subjects shows a polyclonal pattern of all the V delta+ subsets. In contrast, most intestinal T-cell lines produce oligoclonal patterns, suggesting a dramatic in vitro selection effect. The cell expansion in culture is generally not required for the TCR heteroduplex analysis, which can therefore be applied to rapidly monitor the T-cell response in a variety of physiologic and autoimmune reactions, substituting the standard approach of TCR cloning and multiple VJ sequencing.

Clonal expansions of V delta 1+ and V delta 2+ cells increase with age and limit the repertoire of human gamma delta T cells

We have investigated the complexity of the human gamma delta T cell repertoire by means of a VJ heteroduplex analysis method. cDNA obtained from peripheral blood mononuclear cells was amplified with V delta 1-C delta or V delta 2-C delta primers. The product was denatured and renatured to allow random reannealing of the strands and the heteroduplexes carrying mismatched junctional sequences were separated from the homoduplexes on polyacrylamide gels. Whenever one or more T cell clones were expanded to over 10% of the polyclonal background, discrete bands of homo- and heteroduplex appeared. This method was applied to the analysis of the peripheral gamma delta compartment from healthy donors and rheumatoid arthritis patients of different ages. While samples from young individuals showed a polyclonal pattern, a clear tendency towards oligoclonality appeared with increasing age, both in normal individuals and rheumatoid arthritis patients. We also show that the VJ junctional sequence derived from the heteroduplex fragments can be successfully used to isolate and characterize the corresponding T cell clones in vitro, even after a period of 1 year. In conclusion, our findings indicate that the complexity of the gamma delta T cell repertoire decreases with age as a consequence of the expansion of a few T cell clones.

Heteroduplex analysis of T-cell receptor gamma gene rearrangements for diagnosis and monitoring of cutaneous T-cell lymphomas

The possibility to detect markers of T-cell clonality at the T-cell receptor (TCR) beta and gamma loci in skin biopsy samples has proven to be helpful for the often difficult clinical and immunohistochemical diagnosis of cutaneous T-cell lymphoma (CTCL). However, particularly at the early stage of the neoplastic infiltration, an emerging clonal pattern at Southern may be obscured by the germline TCR configuration of the predominant dermal and epidermal cell component. Additionally, multiple TCR gamma rearranged bands of variable intensity are often observed, either in the presence or in the absence of a major clone. To overcome these difficulties, we have investigated the T-lymphocyte clonality in selected patients with variable signs of CTCL by means of heteroduplex analysis of the amplified TCR gamma VJ junctions, separated in nondenaturing polyacrylamide gel. This technique has several advantages over standard Southern blot because it is simple, rapid, not radioactive, and likely more sensitive than other polymerase chain reaction-based procedures. In particular, the cases with uncertain or contradictory TCR beta and gamma patterns were solved by the heteroduplex analysis, showing homoduplex or heteroduplex bands of clonal nature. The direct sequence of the VJ junctions, easily obtained from the homoduplex or heteroduplex bands, allowed us to confirm the same clonal marker in two apparently different skin lesions and in different biopsy samples obtained from the same patients, either at the same or different time points, thus emphasizing the utility of this method in monitoring CTCL clinical progression.

T-cell receptor V delta gene usage by tumour reactive gamma delta T lymphocytes infiltrating human lung cancer

In seven human adenocarcinomas and a non-neoplastic granulomatous disease of the lung, gamma delta+ infiltrating lymphocytes (TIL) could be isolated and selectively expanded in vitro upon culture in interleukin-2 (IL-2), without any additional stimuli, indicating a prior activation in vivo. In most cases gamma delta TIL were predominantly V delta 1+, despite a normal V delta 2:V delta 1 ratio in paired peripheral blood lymphocytes, suggesting a possible expansion of this subset in response to localized antigens/superantigens. Moreover, in five patients it was possible to identify a V delta 1- V delta 2- TIL population which by polymerase chain reaction (PCR) analysis was shown to be heterogeneous as V delta gene usage, inclusive of V delta 3,4,5,6,7 and 8. Of note, these V delta regions have not been found in peripheral blood so far. Finally, in all cases, gamma delta TIL displayed killing activity of the autologous tumour, which appeared to be more restricted in the case of V delta 1+ cells. Altogether, these findings suggest a preferential expansion, at the tumour site, of V delta 1+ cells and of cells expressing V delta genes other than V delta 2.

Maternal serum markers. Estimation of the risk of Down's syndrome: a prospective study

The risk of Down's syndrome pregnancies can be estimated by quantitation of maternal serum markers, namely alpha-fetoprotein, unconjugated estriol and human chorionic gonadotropin (triple test). A prospective study of 2892 pregnant women (median age 33.5 years) is reported. The detection rate of Down's syndrome pregnancies was 80% (confidence intervals 45%-100%) when a risk of 1:380 or greater was considered "screen positive", the false positive rate was 13.3% (confidence intervals 12.0%-14.5%). The importance of the accurate assessment of gestational age and the time of blood sampling are emphasized. Our findings are compared with similar studies performed in other laboratories.

T cell receptor heterogeneity in gamma delta T cell clones from intestinal biopsies of patients with celiac disease

In celiac disease large numbers of gamma delta T lymphocytes infiltrate the intestinal epithelia. We have isolated intestinal gamma delta T cell clones from patients with celiac disease and have analyzed their T cell receptor repertoire. T cell lines and clones were obtained from jejunal biopsies of 14 celiac patients and 12 individuals without celiac disease. These were analyzed by staining with monoclonal antibodies against CD3, alpha beta and gamma delta T cell receptor, by Southern blot with gamma- and delta-specific probes and by polymerase chain reaction using V delta-specific oligonucleotides. Intestinal gamma delta cells from patients with celiac disease differed from those of controls with normal jejunal histology in that V delta 1+ cells and V delta 1-V delta 2- cells were significantly increased. There was no evidence of the expansion of one or more clones expressing particular types of gamma delta T cell receptor.

Clonally expanded CD3+, CD4-, CD8- cells bearing the alpha/beta or the gamma/delta T-cell receptor in patients with the lymphoproliferative disease of granular lymphocytes

Among 60 retrospectively assessed patients with the lymphoproliferative disease of granular lymphocytes (LDGL), lymphocytes from only 2 patients had the CD3+, CD4-, CD8- phenotype, rarely observed in normal peripheral blood lymphocytes (about 3%). In this paper we report a detailed study of lymphocytes isolated from these two patients. The cells from patients 1 had the CD3+, CD4-, CD8-, WT31-, beta F1-, TCR delta 1+, Ti gamma A-, BB3+, CD7+, CD16-, CD57+ phenotype, while cells from patient 2 had a phenotype even more rarely observed on normal lymphocytes: CD3+, CD4-, CD8-, WT31+, beta F1+, TCR delta 1-, CD7+, CD16-, CD57+. Thus, in only the first case the cells expressed the gamma/delta T-cell receptor (TCR) on the membrane, while the cells from the second case had the alpha/beta TCR. Genetic studies showed that in case 1 the TCR gamma gene was rearranged and the beta chain gene configuration was germline; the TCR mRNA was of normal size for the gamma chain, while that of the beta chain was truncated. Case 2 had the beta and the gamma genes of the TCR rearranged, but only the alpha and beta mRNA were expressed. In agreement with these findings, the delta chain gene of the TCR was rearranged in case 1 and was deleted in case 2. Cytotoxic activity was absent in cells from case 1 and low in case 2; in the latter, the lytic activity could be up-regulated following incubation with IL-2 or an anti-CD3 monoclonal antibody. Our study indicates that CD3+, CD4-, CD8- lymphocytes are rarely expanded in patients with LDGL. The detection of a lymphoproliferative disease of a CD3+, CD4-, CD8-, alpha/beta + cell may contribute to a better characterization of this novel lymphocytic subpopulation.

Selection by two powerful antigens may account for the presence of the major population of human peripheral gamma/delta T cells

V gamma 9/V delta 2 cells represent a fraction of human gamma/delta cells that is expanded after birth in the periphery, carries markers of activated cells, and becomes a major population in peripheral blood. We found that these cells do not comprise a single population but actually represent two nested sets, the smaller of which, specific for Mycobacterium tuberculosis-pulsed antigen-presenting cells (APC), is contained in a larger set specific for an antigen found on the Molt-4 lymphoma. The larger set, representing 40-80% of all blood gamma/delta cells, is comprised of cells bearing the V gamma 9/C gamma 1 chain. Cells in the smaller, included set have an additional requirement for V delta 2 (and probably for certain permissive junctional regions, since a very small percentage of V gamma 9/V delta 2 cells do not react against mycobacteria-pulsed APC). Optimal stimulation by mycobacteria is dependent on the presence of APC, and is not restricted by classical major histocompatibility complex molecules. Some of the V gamma 9/V delta 2 mycobacteria-specific clones are also stimulated by APC pulsed with different bacteria, such as Listeria monocytogenes and Escherichia coli, indicating that the population includes several different patterns of reactivity. These data establish a relationship in humans between specificity and V gamma/V delta gene usage, and offer an explanation for the peripheral expansion of these gamma/delta cells.

Mechanisms accounting for lymphocytic alveolitis in hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a lung disorder characterized by an exaggerated accumulation of CD8+ T lymphocytes in the pulmonary parenchyma. To investigate the mechanisms accounting for the T cell alveolitis taking place in the lung of HP patients and their pattern of growth, cells recovered from the bronchoalveolar lavage (BAL) of seven patients were evaluated for: 1) the expression of activation markers, including IL-2R (p55 and p75 subunits), HLA-DR and VLA-1 Ag; 2) the ability of IL-2 and IL-4 to induce in vitro proliferation; 3) the capability to synthesize and release IL-2 by determining the levels of IL-2 in BAL cell-free supernatants and by evaluating the presence of mRNA transcripts for IL-2; and 4) the molecular configuration of the beta- and gamma-genes of the TCR. This study demonstrates that a high number of BAL lymphocytes recovered from the lungs of HP patients express activation markers including the p75 chain of IL-2R, VLA-1, and HLA-DR Ag. These cells express the CD3+,CD8+,CD16-,CD56+ phenotype and proliferate in vitro in the presence of IL-2 but do not release this cytokine. Furthermore, IL-2 transcripts could not be detected in BAL resting T lymphocytes. No proliferation was observed in the presence of IL-4. The analysis of the configuration of the TCR beta- and gamma-genes showed a polyclonal pattern, with the exception of one case in which extra bands were observed following digestion with BamHI and EcoRI restriction enzymes. Taken together, our data suggest that the IL-2 system may play a central role in the mechanisms accounting for lymphocytic alveolitis in HP patients. Although the pattern of growth is usually polyclonal, such polyclonal recruitment seems to be biased toward cells that have rearranged and possibly expressed particular V beta or V gamma genes, thus leading to the hypothesis that the events that take place in the lung of these patients may occasionally elicit an oligoclonal expansion of the cells proliferating in lung parenchyma.

Mechanisms accounting for lymphocytic alveolitis in hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a lung disorder characterized by an exaggerated accumulation of CD8+ T lymphocytes in the pulmonary parenchyma. To investigate the mechanisms accounting for the T cell alveolitis taking place in the lung of HP patients and their pattern of growth, cells recovered from the bronchoalveolar lavage (BAL) of seven patients were evaluated for: 1) the expression of activation markers, including IL-2R (p55 and p75 subunits), HLA-DR and VLA-1 Ag; 2) the ability of IL-2 and IL-4 to induce in vitro proliferation; 3) the capability to synthesize and release IL-2 by determining the levels of IL-2 in BAL cell-free supernatants and by evaluating the presence of mRNA transcripts for IL-2; and 4) the molecular configuration of the beta- and gamma-genes of the TCR. This study demonstrates that a high number of BAL lymphocytes recovered from the lungs of HP patients express activation markers including the p75 chain of IL-2R, VLA-1, and HLA-DR Ag. These cells express the CD3+,CD8+,CD16-,CD56+ phenotype and proliferate in vitro in the presence of IL-2 but do not release this cytokine. Furthermore, IL-2 transcripts could not be detected in BAL resting T lymphocytes. No proliferation was observed in the presence of IL-4. The analysis of the configuration of the TCR beta- and gamma-genes showed a polyclonal pattern, with the exception of one case in which extra bands were observed following digestion with BamHI and EcoRI restriction enzymes. Taken together, our data suggest that the IL-2 system may play a central role in the mechanisms accounting for lymphocytic alveolitis in HP patients. Although the pattern of growth is usually polyclonal, such polyclonal recruitment seems to be biased toward cells that have rearranged and possibly expressed particular V beta or V gamma genes, thus leading to the hypothesis that the events that take place in the lung of these patients may occasionally elicit an oligoclonal expansion of the cells proliferating in lung parenchyma.

High prevalence of T-cell receptor V delta 2-(D)-D delta 3 or D delta 1/2-D delta 3 rearrangements in B-precursor acute lymphoblastic leukemias

Rearrangement of the immunoglobulin (Ig) and T-cell receptor (TcR) genes generally has been considered a useful marker of B- and T-cell lineage in lymphoproliferative disorders. However, concomitant rearrangements of Ig and TcR genes have been commonly reported in the most immature lymphoid malignancies, mainly in B-cell precursor acute lymphoblastic leukemia (ALL). To better characterize the nature of this lineage promiscuity, we have analyzed the configuration of the TcR delta locus in 75 B-precursor ALL. The large majority of cases (87%) displayed a rearrangement or deletion at the delta locus. Among the 57 nondeletional rearrangements, two patterns were predominant and both appeared to derive from partial joining: a V delta-(D)-D delta 3 (32/57) and a D delta 1/2-D delta 3 (11/57) type. A single V delta gene (V delta 2) appeared to be involved in the first type of rearrangement. These findings are at variance with T-ALL, where rearrangements 5' to V delta 2 are usually found. It remains to be elucidated whether this incomplete attempt of V delta 2 gene assembly is related to the neoplastic event or represents a physiologic predisposition occurring during early stages of the normal lymphocyte differentiation.

Molecular analysis of human gamma/delta+ clones from thymus and peripheral blood

We analyzed the V gamma and V delta gene usage in TCR-gamma/delta-bearing T cell clones isolated from human peripheral blood and postnatal thymus using V-specific mAbs and Southern and Northern analyses. In peripheral blood most of the gamma/delta cells express the V gamma 9-JP-C gamma 1 chain paired with a delta chain bearing the V delta 2 gene product. This heterodimer is very rare in the postnatal thymus, where a different and less restricted pairing of V gamma 9 and V delta 2 chains is found. These findings indicate that physical constraints cannot explain the overrepresentation of a particular V gamma 9-JP/V delta 2 heterodimer in the peripheral blood, and we discuss alternative mechanisms that may account for this differential distribution. In addition, this analysis allowed us to map the specificity of the delta TCS1 mAb to V delta 1-J delta 1 and to identify at least five different expressed V delta genes.

Pulsed-field gel analysis of human immunoglobulin heavy-chain constant region gene deletions reveals the extent of unmapped regions within the locus

The human immunoglobulin heavy-chain constant region gene locus is organized in three main gene groups, the physical distances of which are unknown. Different types of gene deletions, originated by unequal crossingover, have been found to encompass one or more genes in the locus. We have analyzed some of these deletions by means of pulsed-field gel electrophoresis, which allows resolution of large DNA fragments. By identifying a fragment containing two of the main gene groups and by observing the size reduction of this fragment in subjects with deletions, we were able to estimate the distance between the two groups and better locate the pseudogene in-between.

Human T cells expressing the gamma/delta T-cell receptor (TcR-1): C gamma 1- and C gamma 2-encoded forms of the receptor correlate with distinctive morphology, cytoskeletal organization, and growth characteristics

BB3 and delta-TCS1 monoclonal antibodies identify two distinct nonoverlapping populations of T-cell receptor (TcR) gamma/delta (TcR-1)-positive cells, which express a disulfide-linked and a nondisulfide-linked form of TcR, respectively. BB3+ cells represented the majority of circulating TcR-1+ cells, but they were virtually undetectable in the thymus. On the other hand, delta-TCS1+ cells were largely predominant among TcR-1+ thymocytes but represented a minority in peripheral blood (PB). Similar distributions were observed by clonal analysis of thymocytes or PB TcR-1+ populations. The use of joining region (J)-specific probes indicated that BB3+ and delta-TCS1+ clones displayed different patterns of J rearrangement. Thus, the disulfide-linked form of TcR-1 (BB3+ clones) was associated with the expression of J segments upstream to the C gamma 1 gene segment, whereas the nondisulfide-linked form (delta-TCS1+ clones) was associated with the expression of J segments upstream to C gamma 2. delta-TCS1+ clones, in most instances, exhibited a growth pattern different from that of BB3+ or conventional TcR alpha/beta+ clones as they adhered promptly to surfaces, spread, and emitted long filopodia ending with adhesion plaques. Ultrastructural analyses showed, exclusively in delta-TCS1+ cells, nuclear deformations, uropod formation, and abundant cytoskeletal structures. In addition, immunofluorescence studies of this subset of TcR-1+ cells revealed the presence of abundant microtubules, intermediate filaments, and submembranous microfilaments. Thus, our findings suggest that delta-TCS1+ cells are capable of active motility.

Ontogeny, gene rearrangements and immunophenotype of acute leukaemias

The progressive availability of more sophisticated technologies has over the last few years allowed a more precise definition of the biological properties of acute leukaemia cells. This, in turn, has enabled to recognize the ontogeny of practically all cases, with particular emphasis to acute lymphoblastic leukaemia, the lineage affiliation of which had, for many years remained uncertain in over half of the cases. Here, we shall review the main achievements, obtained with extensive immunotyping coupled to the use of probes for the immunoglobulin and T-cell receptor genes, which have led to these important clinico-biological acquisitions, and discuss specific situations in which this combined phenotypic and genotypic approach (as well as response to cloned growth factors) may be of particular value.

Human peripheral blood lymphocytes bearing T cell receptor gamma/delta. Expression of CD8 differentiation antigen correlates with the expression of the 55-kD, C gamma 2-encoded gamma chain

We analyzed the CD3-associated molecules present on peripheral blood-derived TCR-gamma/delta+ clones that express CD8 surface antigens. Clones were derived by limiting dilution from CD3+WT31- FACS-purified populations derived from several donors. Eight of greater than 300 TCR-gamma/delta+ clones analyzed expressed CD8 and reacted with delta-TCS-1 mAb. Cell numbers suitable for more detailed analyses could be obtained from four clones, including one derived from thymus. Analysis of CD3-associated TCR molecules immunoprecipitated by anti-Leu-4 (anti-CD3) mAb under conditions that preserve the CD3/TCR association (1% digitonin) showed a predominant 55-60-kD molecule both under reducing and nonreducing conditions. On the other hand, the delta-TCS-1-reactive molecules immunoprecipitated from 25 CD3+ delta-TCS-1+ CD8- clones, in all instances, displayed a 40-44-kD mol mass. In two-dimensional PAGE, TCR-gamma molecules precipitated from delta-TCS-1+ CD8+ clones appeared more acidic than those of BB3+ or delta-TCS-1+ CD8+ clones. Southern analysis confirmed that this type of non-disulphide-linked TCR-gamma/delta is also coded for by the C gamma 2 gene segment.

Mitochondrial DNA polymorphism in four Sardinian villages

Polymorphism of mitochondrial DNA has been studied in two highland (Desulo, Tonara) and in two lowland (Galtellì, Orosei) Sardinian isolates, formerly subjected to different selective pressure due to malaria, and in 103 individuals from Northern Italy (Bergamo area), where malaria never appeared to be endemic. Two mitochondrial restriction endonuclease patterns (morphs) never described before have been found, one in the Bergamo and Orosei samples, and the other one only in Orosei. Four new mitochondrial types (mitotypes) due to different combinations of morphs have been identified; two of them have been found only in Sardinia, but with such a low frequency that they cannot be defined as typical Sardinian mitotypes. One mitotype (BamHI-morph 3, MspI-morph 4, AvaII-morph 9 and HaeII-morph 1) showed a significantly higher frequency in the highland rather than in the lowland Sardinian villages or in the Bergamo area. Since this mitotype has been found at a relatively high frequency in Central and Southern Italy, while it has been reported to be rare in Caucasians of Central European origin and absent in other ethnic groups (Africans, Chinese, Japanese and Israeli Jews), we suggest it may represent an ancient Mediterranean type. The analysis of these data suggests that drift or other evolutive forces different from malaria might be the major cause of mitochondrial DNA variation in Sardinia.

Antigen recognition by human T cell receptor gamma-positive lymphocytes. Specific lysis of allogeneic cells after activation in mixed lymphocyte culture

These experiments were designed to define the ability of human TCR-gamma+ cells to recognize allogeneic cells. TCR-gamma+-enriched populations were obtained by treating peripheral blood E-rosetting cells with anti-CD4 and anti-CD8 mAbs. The resulting populations were CD2+4-8- expressed variable proportions of CD3+ cells (40-90%), and did not react with the WT31 mAb, which is specific for a framework determinant of the alpha/beta heterodimer that serves as receptor for antigen on most human T lymphocytes. After mixed lymphocyte culture with irradiated allogeneic cells for 7 d and 3 additional days in rIL-2 (100 U/ml), cells underwent proliferation in three of five individuals tested. In addition, MLC-derived cells lysed 51Cr-labeled PHA-induced blasts derived from the allogeneic cells used as stimulator, but not allogeneic unrelated or autologous blast cells. No cytotoxicity against autologous or allogeneic target cells could be induced by culturing CD3+4-8-WT31- lymphocytes in MLC with irradiated autologous cells. Surface iodination of allogeneic MLC-activated CD3+4-8-WT31- cells followed by lysis in 1% digitonin and immunoprecipitation with anti-CD3 mAb indicated that the CD3-associated molecules consisted of a major 45-kD band and a minor band of 43 kD. Northern blot analysis showed that mRNA for the gamma chain was expressed at high levels, whereas mRNAs for alpha and beta chains were missing. These data support the notion that TCR-gamma rather than TCR-alpha/beta is expressed in allospecific CD3-4-8-WT31- cell populations. Clones were further derived from MLC-stimulated CD3+4-8-WT31- populations. All the seven clones studied in detail maintained the surface phenotype as well as the cytolytic pattern of the original MLC populations, thus only specific allogeneic PHA-induced blasts were lysed. NK-sensitive as well as NK-resistant tumor targets were variably susceptible to lysis; therefore, specific cytolytic activity against allogeneic cells was not necessarily linked to the expression of MHC-nonrestricted cytotoxicity against tumor cells.

Nonrandom TRG gamma variable gene rearrangement in normal human T cells and T cell leukemias

To estimate the extent of the TRG gamma variable (V) gene repertoire used in human T cell ontogeny, we have analyzed the variety of V gamma gene rearrangements in a large series of T and non-T acute and chronic leukemias. A limited heterogeneity of rearranged fragments was observed: only 13 types of differently rearranged fragments, four of which occurred only once, were found among 80 rearranged chromosomes. Furthermore, in the leukemic population as a whole, the frequency distribution of the most common types of rearranged V gamma gene-containing fragments appeared to be nonrandom (p less than 0.01). Of interest is the clear preference for functional vs. nonfunctional V gamma genes (nonfunctional genes being those which carry frameshifts or nonsense mutations but which presumably can still rearrange due to their conserved signal sequences). We discuss the possibilities that this preference may result either from selection of the TRG gamma product at some stage during T cell development or, alternatively, from an intrinsic, antigen-independent polarity in V gamma gene activation.

CD3+4-8-WT31-(T cell receptor gamma+) cells and other unusual phenotypes are frequently detected among spontaneously interleukin 2-responsive T lymphocytes present in the joint fluid in juvenile rheumatoid arthritis. A clonal analysis

T lymphocytes (E rosetting cells) isolated from the joint fluid of four patients with juvenile rheumatoid arthritis (JRA) were first analyzed for surface antigen expression. Approximately 15% of cells were CD25+ (interleukin, IL, 2 receptor positive), in addition, a remarkable proportion of cells expressed the CD2+3- phenotype. CD3+ cells outnumbered the sum of CD4+ and CD8+ cells as well as the cells reactive with the WT31 monoclonal antibody (which recognizes a framework determinant of the alpha/beta T cell receptor). Purified T cells were cloned under culture conditions (1% phytohemagglutinin, PHA plus IL2) which allow clonal expansion of most peripheral blood T lymphocytes. Under these conditions proliferating cells ranged from 25 to 65%; clones (derived from microcultures containing 0.5 or 0.25 cells/well) were tested for cytolytic activity against P815 cells (in the presence of PHA) or against the natural killer (NK)-sensitive K562 target cells. Fifty-four percent and 73% of clones obtained from the two patients with the polyarticular form of the disease displayed cytolytic activity in the lectin-dependent assay. Cytolytic clones were 22 and 29% in the two patients with single joint involvement. About half of all cytolytic clones displayed NK-like activity. Surface antigen analysis revealed that, in addition to conventional CD3+4+8- and CD3+4-8+, a noticeable fraction of clones (50/202) displayed unusual surface phenotypes. In particular, 33/50 coexpressed CD4 and CD8 antigens; 7/50 were CD2+3-4-8- and displayed NK-like activity; 10/50 expressed CD3 but lacked both CD4 and CD8 antigen and did not react with the WT31 monoclonal antibody. In order to allow selective growth of IL2-responsive cells, T lymphocytes were also cloned directly in IL2. As much as 57% of all clones thus obtained (48/84) displayed cytolytic activity. Moreover, about half expressed unusual surface phenotypes including CD2+3-4-8-, CD3+4+8+ and CD3+4-8-WT31-. Given the accumulation at the site of the joint involvement of unusual T cells, most of which displayed cytolytic activity and were likely to represent cells activated in vivo (IL2 responsive), one may speculate that these cells may be involved in the injury process.

Genotypic characterization of common acute lymphoblastic leukemia may improve the phenotypic classification

The reactivity of five anti-B monoclonal antibodies (McAb)-OKB2 (CD24), B4 (CD19), Leu12 (CD19), BA1 (CD24), B1 (CD20)--as well as the presence of cytoplasmic immunoglobulins (CyIg) were assessed in 100 cases of common acute lymphoblastic leukemia (cALL) at presentation (TdT+, J5 [CD10]+, HLA-Dr+). All cases studied revealed one or more B-cell related markers and a hierarchy in their expression was documented: OKB2 was positive in all cases tested (100%), B4 was expressed in 96.4% of cases, Leu12 in 95.8%, BA1 in 94.9%, B1 in 18.3%, and CyIg in 23%. Further evidence of the B-cell origin of cALL was obtained by molecular analyses at the DNA level which demonstrated the presence of an Ig heavy chain gene rearrangement in all 37 cases assessed, while 37.8% showed a light chain gene reorganization. A genomic subclassification of cALL demonstrated that the majority of cases showed an immature molecular configuration with one (8.1%) or both (54.1%) Ig heavy chain alleles rearranged and a germ-line configuration of the light chain genes; 27% revealed a heavy chain gene involvement and one k allele rearranged. Only four cases (10.8%) showed a more mature configuration with both k alleles rearranged or a gamma chain gene involvement. This study confirms that cALL is characterized by the proliferation of immature B-lineage-committed elements and indicates that the leukemic cells are blocked at different levels of B-differentiation which may be recognized with the use of multiple phenotypic or genotypic B-cell-related markers.

Human CD3+4-8-WT31- T lymphocyte populations expressing the putative T cell receptor gamma-gene product. A limiting dilution and clonal analysis

The small peripheral blood CD3+ T cell population lacking both CD4 and CD8 surface antigens has been analyzed in the present study. Enriched CD3+4-8- populations were obtained by depletion with anti-CD4 or anti-CD8 monoclonal antibodies (mAb) and complement. The resulting populations contained greater than 99% CD2+ cells, whereas CD3+ represented approximately 50%. Virtually all of the cells were CD4-8- and did not react with the WT31 mAb, specific for a framework determinant of the alpha/beta T cell receptor (TCR). In order to analyze the molecular nature of CD3-associated molecules in CD3+WT31- populations, cells were stimulated with 0.5% phytohemagglutinin (PHA) for 24 h and expanded for an additional 7-14 days in interleukin 2 (IL 2). The resulting cells were greater than 95% CD3+ and expressed neither CD4/CD8 nor WT31 antigen. Cell surface iodination followed by cross-linking and immunoprecipitation with anti-CD3 mAb showed that CD3-associated molecules consisted of a major 45-kDa band and a minor band of 43 kDa. Thus, whereas CD3-associated molecules isolated from polyclonal CD3+WT31+ populations (expanded in IL 2 under the same culture conditions) appeared as diffuse bands, CD3-associated molecules isolated from CD3+WT31- populations displayed a homogeneous molecular mass. Northern blot analysis revealed the presence of mRNA for the TCR gamma chain whereas the mRNA for the alpha chain was mostly represented by a truncated (1.2 kb) form. Also small amounts of a nonproductive mRNA for the beta chain were detected. Freshly isolated CD3+WT31--enriched populations proliferated in response to PHA and concanavalin A, moreover, IL 2 was detected in the culture supernatants after cell stimulation. By applying culture conditions which allow virtually all T cells to undergo clonal expansion, approximately 1/3 CD3+WT31- were clonogenic. In addition, the large majority of proliferating microcultures lysed the K562 cell line and about half the natural killer (NK)-resistant fresh melanoma target cells. A large number of clones derived from CD3+WT31- enriched populations by limiting dilution has been further analyzed. More than 95% of the clones were CD3+4-8-WT31-; 12/15 clones analyzed in more detail displayed NK activity and 6/15 lysed melanoma cells; in addition, all lysed P815 target cells in the presence of PHA, thus indicating that all the clonogenic CD3+WT31- cells have a cytolytic potential.

Chronic T-cell leukaemias. A variant of T-prolymphocytic leukaemias: morphological, immunological and clinical characterization of 2 cases

In this study we describe 2 patients who appear to suffer from a morphological, cytochemical and clinico-haematological variant of T-prolymphocytic leukaemia (T-PLL). The cells were smaller than typical prolymphocytes, with a regular nucleus containing a smaller and less prominent nucleolus; the alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (AP) cytochemical reactions showed a weaker pattern of positivity in this variant compared to T-PLL. No immunological differences were found between the two conditions with regard to membrane expression and functional behavior of the cells. The clinical course and the outcome of the patients appears to be different: aggressive and rapidly fatal in T-PLL; thus far well-controlled in the T-PLL variant. From a molecular point of view, both cases showed a monoclonal rearrangement of the T-cell receptor beta-chain gene.