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Interferon-gamma and growth factor production by murine T cells derived from three different lymphoid tissues.

Various antigen-presenting cells and the environment in different lymphoid tissues have been suggested to influence the type of lymphokine produced by T cells. We have investigated the mitogen-induced proliferation, interferon-gamma (IFN-gamma) and growth factor production by cells isolated from spleen, mesenteric and peripheral (axillary, brachial and inguinal) lymph nodes (LN). We found that stimulation with concanavalin A or staphylococcus enterotoxin B induced IFN-gamma synthesis in spleen cells but not in LN cells. Proliferation and growth factor production were comparable in the three cell populations. The addition of the phorbol ester phorbol 12-myristate 13-acetate (PMA), which is commonly used as a substitute for accessory cells, did not influence the IFN-gamma synthesis by LN cells. The growth factor production was, on the other hand, elevated by the addition of PMA. A high number of IFN-gamma-producing peripheral LN cells were obtained if they were stimulated in the presence of splenic adherent cells. The growth factor synthesis was marginally affected by the presence of these cells. Thus, splenic adherent cells provide a co-stimulatory signal to the T cell necessary for IFN-gamma synthesis.

Animals↗

The value of EUS in predicting the response of gastric mucosa-associated lymphoid tissue lymphoma to Helicobacter pylori eradication.

BACKGROUND: Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is associated with Helicobacter pylori infection, and regression of the tumor has been described after its eradication. OBJECTIVE: To determine the value of EUS, in addition to other clinical/endoscopic features, in predicting the response of low-grade MALT lymphoma to H pylori eradication. DESIGN: A retrospective, single-center study. SETTING AND PATIENTS: Twenty-two patients with primary gastric MALT lymphoma were identified through a retrospective review of charts of patients seen at the American University of Beirut Medical Center. Only 19 patients with histopathologically confirmed gastric MALT lymphoma and H pylori infection who had EUS staging were included in the study. MAIN OUTCOME MEASUREMENTS: Regression of the gastric MALT lymphoma as determined by follow-up endoscopy and mucosal biopsies. RESULTS: Patients with disease restricted to the gastric mucosa had a significantly higher rate of complete remission after H pylori eradication compared with patients who had disease infiltrating into the gastric submucosa (77.8% vs 12.5%, P value .007). There was no statistical difference in terms of the mean follow-up time to achieve such response (P value .212). Age, sex, location of the tumor within the stomach, and endoscopic appearance did not correlate with the probability of complete remission of the MALT lymphoma. LIMITATIONS: The limitations include a retrospective design and a relatively small sample population. CONCLUSION: EUS determination of the invasion depth of gastric MALT lymphoma helps predict a complete response to H pylori eradication.

Aged↗

Duodenal mucosa-associated lymphoid tissue lymphoma: treatment with oral cyclophosphamide.

Small cell mucosa-associated lymphoid tissue (MALT) lymphomas rarely affect the duodenum, and optimal treatment has not been defined. The aim of this case series was to determine the clinical features and outcome of duodenal MALT lymphoma in four patients (three men, one woman; median age 52 yr) treated with cyclophosphamide p.o. Initial manifestations were abdominal pain (n = 4), vomiting (n = 2), and an obstructive syndrome (n = 1). MALT lymphoma was diagnosed on the basis of endoscopic biopsies. It was localized in the duodenum in three cases and involved the entire small bowel in one case. Tumor infiltration was limited to the duodenal wall in one case and was associated with locoregional lymphadenopathy in three cases. The patients were graded EI (n = 1) and EII1 (n = 3), respectively, according to the Ann Arbor classification revised by Musshof. Cyclophosphamide, 100 mg daily, was administered p.o. for 18 months. Gastroscopy with biopsies, radiography of the small intestine and abdominal CT (CT) were performed every 6 months. Complete remission was defined by morphological and histological normalization, and partial remission as morphological normalization only. Follow-up lasted from 9 to 65 months. Three patients were in complete remission at 18 months: two relapsed after 2 yr and one was still in complete remission at 65 months. The patient with 9 months of follow-up was in complete remission at 6 months. The two patients who relapsed did not complain of symptoms, and no morphological abnormalities were seen. Relapse was diagnosed on histological grounds. Cyclophosphamide monotherapy p.o. thus seems well adapted to this slowly progressive disease, but it is unclear whether it should be resumed in the case of histological relapse or only in the case of symptomatic relapse. (Am J Gastroenterol 2000;95:536-539. (O 2000 by Am. Coll. of Gastroenterology)

Administration, Oral↗

Treatment of gastric mucosa-associated lymphoid tissue lymphoma: Helicobacter pylori eradication and beyond.

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the paradigm of lymphomas developing in extranodal areas after antigen stimulation. In the stomach, Helicobacter pylori colonization induces the appearance of MALT and, eventually, MALT-derived lymphoma. This type of lymphoma is initially a localized form of disease, but may disseminate and transform into high-grade lymphoma, making full staging (as for nodal lymphomas) and endoscopic ultrasonography to evaluate the penetration of the lymphoma through the gastric wall mandatory. In localized gastric MALT lymphoma, the first step in treatment is eradication of H. pylori, which results in 60-90% regression. This response is maintained for years in most patients, with only 10-15% relapse, frequently precipitated by H. pylori reinfection. A component of high-grade lymphoma, penetration to gastric serosa or beyond and translocation t(11;18) are the main factors that make lymphoma resistant to eradication. Surgery or radiotherapy can cure localized lymphomas in 75-90% of patients. Chemotherapy with alkylating agents, combination chemotherapy and purine analogs, and anti-CD20 antibodies can also induce remission of localized lymphomas refractory to eradication, as well as locally advanced and disseminated lymphomas. The optimum chemotherapy treatment for advanced disease has not yet been established; however, combination therapy, including purine analogs with or without anti-CD20, may be a promising option. Despite histological responses and prolonged remissions, residual molecular disease can be demonstrated in most cases treated with H. pylori eradication, radiotherapy or alkylating agents, and even after more intense chemotherapy, although this does not seem to lead to late relapses. High-grade gastric MALT lymphoma should be treated with chemotherapy, with cyclophosphamide, doxorubicin, oncovin and prednisone being the best first-line option. All gastric MALT lymphomas associated with H. pylori should receive eradication treatment in addition to other required treatment.

Anti-Infective Agents↗

Molecular analysis of mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexa.

Lymphomas of mucosa-associated lymphoid tissue (MALT) are a distinct subgroup of extranodal B-cell non-Hodgkin's lymphomas. Most studies have failed to demonstrate the clonal rearrangement of BCL-1, BCL-2 or c-MYC genes for MALT lymphomas. Further, alteration of the p53 gene is rarely demonstrated in low-grade MALT lymphomas, but can be detected in high-grade disease. Lymphomas of the ocular adnexa represent approximately eight percent of all extranodal lymphomas, most of which are MALT lymphomas, but few studies had explored the alterations of BCL-1, BCL-2, c-MYC and p53 genes specifically for ocular MALT lymphomas. We investigated the changes to BCL-1, BCL-2, c-MYC and p53 genes in these lymphomas for Taiwanese patients. Clonal rearrangement for immunoglobulin heavy-chain (IgH), BCL-1, BCL-2, c-MYC and p53 genes was examined for 16 cases of ocular MALT lymphoma. Restriction-length polymorphism and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the DNA, corresponding to exons 5 through 9, followed by DNA sequencing, were utilized to analyze the possible mutations of the p53 gene for these tumors. Thirteen of the cases revealed rearranged IgH genes using Southern blotting or PCR. No rearrangement of BCL-1, BCL-2, c-MYC or p53 genes was discovered, with point mutation of the p53 gene in one case. As for other types of MALT lymphomas, BCL-1, BCL-2 and c-MYC genes are not implicated in the pathogenesis of the ocular sub-group. Although alteration of the p53 gene is rare for low-grade ocular MALT lymphoma, its role in disease progression merits further research.

Adolescent↗

Antibiotic treatment of gastric lymphoma of mucosa-associated lymphoid tissue. An uncontrolled trial.

BACKGROUND: Gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is related to Helicobacter pylori infection and may depend on this infection for growth. OBJECTIVE: To determine the response of gastric MALT lymphoma to antibiotic treatment. DESIGN: Prospective, uncontrolled treatment trial. SETTING: University hospital referral center and three collaborating university and community hospitals. PATIENTS: 34 patients with stage I or stage II N1 gastric MALT lymphoma. INTERVENTION: Two of three oral antibiotic regimens--1) amoxicillin, 750 mg three times daily, and clarithromycin, 500 mg three times daily; 2)tetracycline, 500 mg four times daily, and clarithromycin, 500 mg three times daily; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times daily--were administered sequentially (usually in the order written) for 21 days at baseline and at 8 weeks, along with a proton-pump inhibitor (lansoprazole or omeprazole) and bismuth subsalicylate. MEASUREMENTS: Complete remission was defined as the absence of histopathologic evidence of lymphoma on endoscopic biopsy. Partial remission was defined as a reduction in endoscopic tumor stage or 50% reduction in the size of large tumors. RESULTS: 34 patients were followed for a mean (+/-SD) of 41 +/- 16 months (range, 18 to 70 months) after antibiotic treatment. Of 28 H. pylori-positive patients, 14 (50% [95% CI, 31% to 69%]) achieved complete remission, 8 (29%) achieved partial remission (treatment eventually failed in 4 of the 8), and 10 (36% [CI, 19% to 56%]) did not respond to treatment. Treatment failed in all 6 (100% [CI, 54% to 100%]) H. pylori-negative patients. Patients with endoscopic appearance of gastritis (stage I T1 disease) were most likely to achieve complete remission within 18 months. Tumors in the distal stomach were associated with more favorable response than tumors in the proximal stomach. CONCLUSIONS: A subset of H. pylori-positive gastric MALT lymphomas, including infiltrative tumors, may respond to antibiotics. The likelihood of early complete remission seems to be greatest for superficial and distal tumors.

Anti-Bacterial Agents↗

[Non-gastric mucosa-associated lymphoid tissue (MALT) lymphomas: analysis of 14 patients].

BACKGROUND: Mucosa-associated lymphoid tissue (MALT) lymphomas are a well defined group of B-cell non-Hodgkin's lymphomas, that arise in a wide variety of extranodal sites, most frequently in the stomach and related to Helicobacter pylori infection. The aim of the present study was to analyze the presenting features, natural history and outcome in 14 patients with non-gastric MALT lymphoma. PATIENTS AND METHODS: The main clinical data, treatment and outcome were recorded for the 14 patients with non-gastric MALT lymphoma diagnosed at a single institution in a 12 year period. The median age was 68 years and 13 patients were females. Diagnosis was made according to the REAL classification criteria. RESULTS: The initial location was thyroid (3 patients), parotid (three), submaxilar gland (three), skin (two), Waldeyer's ring (one), breast (one), lung (one), small bowel (one), liver (one) and ovary (one). At diagnosis 3 patients had > or = 2 extranodal involved sites. Autoimmune disorders were present in 5 patients: Hashimoto's thyroiditis (three), Sjögren's syndrome (one) and both (one). Two patients had a poor performance status (ECOG > 1) and B-symptoms. Five patients (36%) were in stage IV, two of them because of bone marrow infiltration. All patients had a normal serum LDH level, and 5 had high beta 2-microglobulin level. The treatment consisted in surgical resection (2 patients), surgery and radiotherapy (one), surgery and chemotherapy (two), chemotherapy and radiotherapy (two) and chemotherapy alone (7 patients, three of them with doxorubicin-containing regimens). Twelve patients were evaluable for response. Complete response, partial response and failure rates were 75, 17 and 8%, respectively. Two of the 11 responders progressed, one of them with advanced stage disease. The actuarial 4-year disease-free survival was 77% (CI 95%: 47-100%). After a median follow-up of 3.4 years, 100% of the patients were alive. CONCLUSION: Non-gastric MALT lymphomas may be associated with autoimmune disorders, may present as disseminated disease and have a very good outcome.

Adult↗

Malignant lymphoma of gastric mucosa-associated lymphoid tissue in Jamaica.

The recently appreciated concept of Mucosa-Associated Lymphoid Tissue (MALT) and the characteristics of the lymphomas arising therein are discussed with reference to the clinical, histological and immunohistochemical features of the first four cases of gastric MALT lymphomas diagnosed at the University Hospital of the West Indies. These tumours are low-grade B-cell lymphomas, which may undergo high-grade transformation. They are aetiologically associated with Helicobacter pylori (H pylori) infection in the stomach and may be cured in the early stages with antibiotics. Our cases were diagnosed from gastrectomy specimens removed for suspected carcinoma. All were high-grade, and associated with H pylori; 3 cases presented as advanced disease. Documentation of the features of these lymphomas will increase awareness and earlier recognition.

Aged↗

Laparoscopy-assisted colon resection for mucosa-associated lymphoid tissue (MALT) lymphoma in the cecum.

Colonic MALToma (mucosa-associated lymphoid tissue lymphoma) has not been well investigated compared to stomach MALToma which is related to Helicobacter pylori infection. We report the uncommon case of MALToma in the cecum initially identified as submucosal tumor, successfully treated by laparoscopy-assisted resection with systemic lymphadectomy. As the metastatic ability and sensitivity against chemotherapy of colonic MALToma is not known, temporally, this treatment seems to be the best choice.

Adult↗

Co-localization of vimentin and cytokeratins in M-cells of rabbit gut-associated lymphoid tissue (GALT).

The occurrence of cytokeratins, vimentin, and desmin in the dome epithelia and adjacent non-dome epithelia in four locations of gut-associated lymphoid tissues (GALT) of adult and newborn rabbits (Peyer's patches, sacculus rotundus, caecal lymphoid patches and appendix) was studied with monoclonal antibodies, using the indirect immunoperoxidase technique. In all locations investigated in adult animals, antibodies specific for vimentin labelled (1) M-cells, which engulf intra-epithelial lymphocytes, (2) columnar epithelial cells at the base of the domes lacking an apparent contact with lymphocytes ("immature" M-cells), and (3) flat cells, which lie in the lamina propria under the dome epithelium, and which line the basal lamina with thin cytoplasmic processes. In newborn rabbits, columnar epithelial cells resembling the immature M-cells of adults were selectively stained with vimentin antibodies. In M-cells, the strongest immunoreactivity was present in the perinuclear region and close to the pocket membrane, whereas the most apical and most basal parts of the cytoplasm showed no vimentin-immunoreactivity. Enterocytes in the dome epithelium and in the non-dome epithelium were vimentin-negative. M-cells and enterocytes bound antibodies against cytokeratin peptides 18 and 19 in adult and newborn animals. Compared with enterocytes, M-cells showed less intense staining for cytokeratins. Dome epithelia and no-dome epithelia did not contain desmin-immunoreactive cells. The results suggest that vimentin is a sensitive marker for M-cells in rabbit GALT.

Animals↗

Leishmania infantum promotes replication of HIV type 1 in human lymphoid tissue cultured ex vivo by inducing secretion of the proinflammatory cytokines TNF-alpha and IL-1 alpha.

Parasitic infections such as leishmaniasis can modulate the life cycle of HIV-1 and disease progression. Coinfection with HIV-1 and Leishmania has emerged as a serious threat in countries where both pathogenic agents are widespread. Although there are numerous clinical reports illustrating the cofactor role played by Leishmania in HIV-1-infected patients, there is still no information on the contribution of Leishmania to the biology of HIV-1 in human lymphoid tissue that is considered a major in vivo site of virus production. In this study we explored the modulatory effect of Leishmania on the process of HIV-1 infection using ex vivo cultured human tonsillar tissue. We found that the protozoan parasite Leishmania enhances both HIV-1 transcription and virus production after infection of human tonsillar tissue infected ex vivo with viral strains bearing various coreceptor usage profiles. Studies conducted with pentoxifylline and neutralizing Abs revealed that the Leishmania-mediated increase in HIV-1 production was linked to a higher production of TNF-alpha and IL-1alpha. Our findings help to unravel the molecular mechanism(s) through which the two microorganisms interact and provide information that may be useful for the design of more effective therapeutic strategies aimed at controlling disease progression in persons dually infected with HIV-1 and Leishmania. This work also indicates that histocultures of human lymphoid tissue infected by both pathogens represent an ideal experimental cell system to dissect interactions occurring between HIV-1 and an opportunist pathogen in a human microenvironment that approximates conditions prevailing under physiological situations.

Animals↗

Malignant diseases of hematopoietic and lymphoid tissues in Chernobyl clean-up workers.

INTRODUCTION: The question as to whether the incidence of leukemias and malignant lymphomas among the clean-up workers increased in 18 years after the catastrophe is still a point of much controversy. Precise diagnosis of the main forms of hematopoietic malignancies and comparison of these data with those in the general population will be helpful in estimating thr relative contribution of the radiation factor to the overall incidence of such pathologies. MATERIALS AND METHODS: In all, 187 consecutive cases of malignant diseases of hematopoietic and lymphoid tissues in Chernobyl clean-up workers were analyzed in Ukrainian Reference Laboratory in 1996-2003. A total of 1942 consecutive patients of general population, mainly the residents of Kyiv city and district, diagnosed in References Laboratory at the same period comprised the group of comparison. The morphology and cytochemistry of bone marrow and peripheral blood cells were studied. Immunocytochemical techniques (PAP, APAAP, ABC) and the panel of monoclonal antibodies to differentiation antigens of leukocytes were employed for immunophenotyping leukemic cells. RESULTS: Various types of malignant disease of hematopoietic and lymphoid tissues were registered in Chernobyl clean-up workers under study including myelodysplastic syndromes (nine patients), acute lymphoblastic leukemia (eight) and acute myeloblastic leukemia (31), chromic myeloid leukemia (17), multiple myeloma (17) and other forms of chromic myeloproliferative and lymphoproliferative disease including B-cell chromic lymphocytic leukemia (49 patients). CONCLUSION: The verified diagnosis of tumors of hematopoietic malignancies according to modern classification (EGIL, WHO) could be the prerequisite for further analytical epidemiology study of leukemias that may be related to the Chernobyl accident.

Adult↗

Bone marrow-derived chimerism in non-irradiated, cyclosporin-treated rats receiving microvascularized limb transplants: evidence for donor-derived dendritic cells in recipient lymphoid tissues.

Tolerance to donor transplantation antigens develops when recipients are made chimeric with donor bone marrow. To establish chimerism, the haemopoietic system of recipients typically is severely compromised. We report on a system in which chimerism develops without ablative therapies. Immunosuppression with cyclosporin A allowed the lower limb of a rat to be replaced by a microvascularized transplant from a fully allogeneic donor. Many donor-derived cells populated recipient lymph nodes and spleen, and most had the large size, irregular shape and strong major histocompatibility complex (MHC) class II expression that typify dendritic cells. Donor cells were not found in the macrophage-rich regions of lymphoid tissues, but instead occupied splenic white pulp and lymph node cortex. The donor cells were derived from radiosensitive marrow precursors, as chimerism was abolished if the grafted limb was irradiated, or if muscle and skin flaps devoid of bone were grafted. Donor cells were rare or not detectable in blood, thymus and liver. Whereas lymphoid chimerism was prominent following limb transfer, donor cells were not detected 1-2 weeks after an injection of two femur equivalents of a marrow suspension. We suggest that dendritic cells that undergo rapid turnover in lymphoid organs are replaced from allogeneic precursors in bone grafts. The combination of cyclosporin and vascularized bone provides a means for inducing chimerism in lymphoid tissues of non-irradiated recipients.

Animals↗

[Cellular composition of tracheal lymphoid tissue in children in their first year of life].

By means of morphometrical methods in histological preparations the quantitative relations of various cell types of lymphoid formations has been studied in newborns and in suckling children. The trachea in the newborns practically does not possess any morphological substrate in the form of lymphoid accumulations, responsible for immune defense of the organ from any external influence. Development of the lymphoid tissue begins in the suckling age and its cytoarchitectonics depends on their localization in the organ's wall. A special place among the accumulations of the lymphoid cells occupy connective tissue spaces of the tracheal glands, where besides lymphocytes and fibroblasts a great amount of plasma cells is situated. Under epithelium these cells are in the least amount, in the prenoduli they are of an intermediate amount. In all the lymphoid structures investigated reproductive function is absent; this is proved by absence of blasts and mitotically dividing cells. Increase in amount of the tracheal lymphoid formations in all age groups studied takes place at the expense of cells migration across blood vessels.

Age Factors↗

An application of linear output error modelling for studying lymphocyte migration in peripheral lymphoid tissues.

Lymphocyte recirculation between lymphatic and blood vessels and migration through tissues are essential mechanisms underlying immunological surveillance. However, the kinetics of lymphocyte migration through lymphoid tissues remains poorly understood. The present study of lymphocyte migration, based on a sheep model and entailing the long term cannulation of blood vessels and lymphatic vessels efferent from lymph nodes, represents the first attempt to apply control engineering based models to overcome some of the experimental impediments to understanding the complex phenomena involved in lymphocyte migration. An output error model order (1,2,nk) was systematically selected under given criteria from four classes of Linear Time-Invariant Single-Input Single-Output, (LTI-SISO) systems to represent the peripheral lymph node system. The unit impulse responses were simulated under noise free conditions and their features were extracted to describe the dynamics of the system. The findings from this study revealed novel information about several aspects of the dynamics of lymphocyte migration.

Animals↗

Immunohistochemical study on follicular dendritic cell of conjunctiva-associated lymphoid tissue.

We performed an immunohistochemical study of follicular dendritic cells (FDC) in the follicular area of the conjunctiva-associated lymphoid tissue (CALT). Hartley guinea pigs were sensitized with a topical application of an emulsion of ovalbumin and Freund's complete adjuvant in the eye. They were divided into four groups. The control (group A) underwent no sensitization. The sensitized animals were studied at 1 week (group B1) or 2 weeks (group B2) after the sensitization. Additional sensitization at 1 week after the initial sensitization was also performed (group C). Histological methods included methylgreen pyronine staining, alpha-naphthylacetate esterase staining, and enzyme-antibody method against S-100 protein. The uptake of topically applied peroxidase-anti-peroxidase (PAP) in CALT was also examined histologically. In each group, positive reticular patterns by alphanaphthyl acetate esterase staining and immunoperoxidase staining with anti-S-100 protein antiserum were found in the CALT follicular area. The positively stained cells were found to be dendrite cells by immunoelectronmicroscopy. An uptake of PAP was found in the CALT follicular area, suggesting the function of trapping and retaining antigen-antibody complex by FDC. It was concluded that dendritic cells in the CALT follicular area were identified to be FDC.

Animals↗

Production of IgA monoclonal antibody against Shiga toxin binding subunits employing nasal-associated lymphoid tissue.

We established an IgA monoclonal antibody (mAb) against Shiga toxin 1 B subunits (Stx1B) from mouse nasal-associated lymphoid tissues (NALT) of BALB/c mice. We have developed an improved protocol in which cross-linked Stx1B is intranasally administered together with cholera toxin. Surface IgA-positive NALT lymphocytes from mice immunized in this manner were enriched and then fused with mouse myeloma cells to produce hybridoma cells. Hybridoma culture supernatants were examined to see if they contain IgA against Stx1B and if they can inhibit carbohydrate recognition by Stx1B. For the latter purpose, we prepared carbohydrate ligands in which globotriose is present on the poly-lysine backbone. The established IgA mAb exhibited saturable and dose-dependent binding to the immobilized Stx1B. Inversely, the binding of the carbohydrate ligands to the immobilized Stx1B was inhibited by the mAb pretreatment. Immunoblotting and SDS-PAGE analysis revealed dimeric IgA. The IgA mAb inhibited the binding of digoxigenin-conjugated Stx1B to natural ligands displayed on a Burkitt's lymphoma cell line, Ramos. These results suggested that surface IgA-positive B cells in the inductive sites of the mucosal immune system in the upper respiratory tract are a potent source for producing IgA mAb against protein antigens with weak immunogenicity such as Stx1B.

Animals↗

A lysis, storage, and transportation buffer for long-term, room-temperature preservation of human clinical lymphoid tissue samples yielding high molecular weight genomic DNA suitable for molecular diagnosis.

Molecular diagnosis of malignant lymphoma depends on the ability to extract high molecular weight genomic DNA. However, collection, storage, and transportation of frozen tissue is time consuming and expensive. We used a simple, low-cost lysis, storage, and transportation buffer (LST) to maintain clinical tissue samples at room temperature for up to 4 weeks before molecular analysis. Immersion of lymphoid tissue in LST at room temperature for 2 to 4 weeks was compared with snap-freezing in liquid nitrogen followed by storage at -75 degrees C. Southern blot analysis using an immunoglobulin heavy chain JH probe yielded identical results in 5 clonal and 6 nonclonal samples. The DNA recovered from the LST of a 12th sample was too degraded to be analyzed; however, the tissue had large zones of geographic necrosis. We also demonstrated that DNA extracted from tissue stored in LST is suitable for amplification by the polymerase chain reaction. Results from 4 of the snap-frozen and LST samples analyzed for rearrangements at the immunoglobulin heavy chain VDJ locus were identical. LST can be used in a clinical laboratory for storing tissue samples at room temperature up to 4 weeks before molecular analysis.

Blotting, Southern↗