Treatment of Large Cartilage Defects in the Knee by Hydrogel-Based Autologous Chondrocyte Implantation: Two-Year Results of a Prospective, Multicenter, Single-Arm Phase III Trial

OBJECTIVE

To evaluate the clinical outcome of a hydrogel-based autologous chondrocyte implantation (ACI) for large articular cartilage defects in the knee joint.

DESIGN

Prospective, multicenter, single-arm, phase III clinical trial. ACI was performed in 100 patients with focal full-thickness cartilage defects ranging from 4 to 12 cm² in size. The primary outcome measure was the responder rate at 2 years using the Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Two years after ACI treatment, 93% of patients were KOOS responders having improved by ≥10 points compared with their pre-operative level. The primary endpoint of the study was met and demonstrated that the KOOS response rate is markedly greater than 40% with a lower 95% CI (confidence interval) of 86.1, more than twice the pre-specified no-effect level. KOOS improvement (least squares mean) was 42.0 ± 1.8 points (95% CI between 38.4 and 45.7). Mean changes from baseline were significant in the overall KOOS and in all 5 KOOS subscores from Month 3 (first measurement) to Month 24 (inclusive) (P < 0.0001). The mean MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score after 24 months reached 80.0 points (95% CI: 70.0-90.0 points) and 92.1 points in lesions ≤ 5 cm².

CONCLUSIONS

Overall, hydrogel-based ACI proved to be a valuable treatment option for patients with large cartilage defects in the knee as demonstrated by early, statistically significant, and clinically meaningful improvement up to 2 years follow-up. Parallel to the clinical improvements, MRI analyses suggested increasing maturation, re-organization, and integration of the repair tissue.

TRIAL REGISTRATION

NCT03319797; EudraCT No.: 2016-002817-22.

Integrative characterization of chronic cigarette smoke-induced cardiopulmonary comorbidities in a mouse model

Cigarette smoke-triggered inflammatory cascades and consequent tissue damage are the main causes of chronic obstructive pulmonary disease (COPD). There is no effective therapy and the key mediators of COPD are not identified due to the lack of translational animal models with complex characterization. This integrative chronic study investigated cardiopulmonary pathophysiological alterations and mechanisms with functional, morphological and biochemical techniques in a 6-month-long cigarette smoke exposure mouse model. Some respiratory alterations characteristic of emphysema (decreased airway resistance: Rl; end-expiratory work and pause: EEW, EEP; expiration time: Te; increased tidal mid-expiratory flow: EF50) were detected in anaesthetized C57BL/6 mice, unrestrained plethysmography did not show changes. Typical histopathological signs were peribronchial/perivascular (PB/PV) edema at month 1, neutrophil/macrophage infiltration at month 2, interstitial leukocyte accumulation at months 3-4, and emphysema/atelectasis at months 5-6 quantified by mean linear intercept measurement. Emphysema was proven by micro-CT quantification. Leukocyte number in the bronchoalveolar lavage at month 2 and lung matrix metalloproteinases-2 and 9 (MMP-2/MMP-9) activities in months 5-6 significantly increased. Smoking triggered complex cytokine profile change in the lung with one characteristic inflammatory peak of C5a, interleukin-1α and its receptor antagonist (IL-1α, IL-1ra), monokine induced by gamma interferon (MIG), macrophage colony-stimulating factor (M-CSF), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) at months 2-3, and another peak of interferon-γ (IFN-γ), IL-4, 7, 13, 17, 27 related to tissue destruction. Transient systolic and diastolic ventricular dysfunction developed after 1-2 months shown by significantly decreased ejection fraction (EF%) and deceleration time, respectively. These parameters together with the tricuspid annular plane systolic excursion (TAPSE) decreased again after 5-6 months. Soluble intercellular adhesion molecule-1 (sICAM-1) significantly increased in the heart homogenates at month 6, while other inflammatory cytokines were undetectable. This is the first study demonstrating smoking duration-dependent, complex cardiopulmonary alterations characteristic to COPD, in which inflammatory cytokine cascades and MMP-2/9 might be responsible for pulmonary destruction and sICAM-1 for heart dysfunction.

The Frequency of EGFR Mutation in Lung Adenocarcinoma and the Efficacy of Tyrosine Kinase Inhibitor Therapy in a Hungarian Cohort of Patients

In the last decades new therapeutic drugs have been developed for the treatment of non-small cell lung cancer (NSCLC) patients. Tyrosine kinase inhibitors (TKIs) significantly increase the progression free survival (PFS) of patients with NSCLC carrying epidermal growth factor receptor (EGFR) mutations. This type of lung cancer occurs mainly among non-smoking women and Asian origin. However, the new ESMO guideline recommends EGFR mutation analysis in every patient with NSCLC, because in patients with activating EGFR mutation, TKIs should be considered as first line therapy. In our recent work, we analyzed data of patients with EGFR-mutant adenocarcinoma from January 2009. The number of patients investigated was 446, among them 44 cases were positive for EGFR mutation. The ratio of positive cases was 9.86 % that is lower than the average mutation rate in Europe and much lower than that found in Asia. The exon 19 deletion was detected in 61.4 % of the patients, while L858R point mutation in exon 21 was observed in 34.1 % of them. In one subject, both exon 19 and 21 mutations were present simultaneously. A rare mutation located in exon 21 was found in another patient. TKI therapy was conducted in 38 patients. The disease control rate by TKI therapy was 85.7 %; primary resistance was documented in five subjects. Non-smoking patients with EGFR mutant adenocarcinoma had the highest benefit from TKI treatment. Our data support the recommendation that EGFR mutation status should be defined in all cases of locally advanced or metastatic lung adenocarcinoma.

[An extremely rare cause of bilateral tension pneumothorax]

CASE REPORT

A middle-aged man presented with the diagnosis of typical spontaneous pneumothorax in the left chest. His management was initiated as usual with a chest drain and he had an uneventful recovery with good expansion of the affected lung up until the third postoperative day. But due to a fatal accident, the patient connected the oxygene supply tube into his thoracic drain. This high pressure caused a left, and a consequent bilateral pneumothorax with massive subcutanous emphysema, being the cause of a preterminal status. Cardio-pulmonary resuscitation was unsuccesfull and the patient died. Intentional suicide was excluded by forensic investigations.

DISCUSSION

According to our knowledge, no similar case with this mechanism of tension pnemuthorax has been published in the literature so far. The pathophysiology is similar to lung damage due to high-pressure ventillation with consecutive tension pneumothorax.

Expression of the somatostatin receptor subtype 4 in intact and inflamed pulmonary tissues

Somatostatin released from capsaicin-sensitive sensory nerves of the lung during endotoxin-induced murine pneumonitis inhibits inflammation and hyperresponsiveness, presumably via somatostatin receptor subtype 4 (sst(4)). The goal of the present study was to identify sst(4) receptors in mouse and human lungs and to reveal its inflammation-induced alterations with real-time quantitative PCR, Western blot, and immunohistochemistry. In non-inflamed mouse and human lungs, mRNA expression and immunolocalization of sst(4) are very similar. They are present on bronchial epithelial, vascular endothelial, and smooth-muscle cells. The sst(4) receptor protein in the mouse lung significantly increases 24 hr after intranasal endotoxin administration as well as in response to 3 months of whole-body cigarette smoke exposure, owing to the infiltrating sst(4)-positive mononuclear cells and neutrophils. In the chronically inflamed human lung, the large number of activated macrophages markedly elevate sst(4) mRNA levels, although there is no change in acute purulent pneumonia, in which granulocytes accumulate. Despite mouse granulocytes, human neutrophils do not show sst(4) immunopositivity. We provide the first evidence for the expression, localization, and inflammation-induced alterations of sst(4) receptors in murine and human lungs. Inasmuch as tissue distribution of this receptor is highly similar, extrapolation of murine experimental results to human conditions might be possible.

Mutational Analysis of IgVH and BCL-6 Genes Suggests Thymic B-cells Origin of Mediastinal (Thymic) B-cell Lymphoma

Mediastinal (thymic) large B-cell lymphoma (MBL) has been defined as a subtype of diffuse large B-cell lymphoma (DLBL) arising in the mediastinum with characteristic clinicopathological features. It has been postulated that MBL arise from non-circulating thymic B-cells and represent a distinct lymphoma entity, however, the histogenesis of the disease is not yet fully understood. In order to clarify the histogenetic derivation of MBL and to determine the relationship of MBL to thymic B-cells we have analyzed the nucleic acid sequences of immunoglobulin (Ig) heavy chain variable region (VH) and 5' noncoding region of BCL-6 genes in normal thymic B-cells and six cases of MBL. Thymic B-cells and tumor cells of MBLs displayed hypermutated VH and/or BCL-6 genes but intraclonal divergence did not associate with these mutations. Since somatic mutations of the IgVH and BCL-6 genes are histogenetic markers of B-cell transit through the germinal centre (GC), these results suggest that both thymic B-cells and MBLs derived from GC or an equivalent environment where B-cells underwent somatic hypermutation. The similar pattern of mutations of IgVH and BCL-6 genes found in thymic B-cells and MBLs further supports the theory that MBLs originate from thymic B-cells.

Investigation of sensory neurogenic components in a bleomycin-induced scleroderma model using transient receptor potential vanilloid 1 receptor- and calcitonin gene-related peptide-knockout mice

OBJECTIVE

Along with their classic afferent function (nociception), capsaicin-sensitive transient receptor potential vanilloid 1 (TRPV1) receptor-expressing sensory nerve terminals exert local and systemic efferent activities. Activation of TRPV1 causes sensory neuropeptide release, which modulates the inflammation process. The aim of the present study was to examine the role of this modulatory role of TRPV1 receptor and that of calcitonin gene-related peptide (CGRP) in bleomycin-induced scleroderma, using transgenic mice.

METHODS

Cutaneous sclerosis was induced with daily subcutaneous injections of bleomycin for 30 days. Control groups were treated with phosphate buffered saline (PBS). TRPV1 receptor gene-deficient (TRPV1(-/-)) mice and CGRP-knockout (CGRP(-/-)) mice and their wild-type (WT) counterparts were investigated. A composite sclerosis score was calculated on the basis of thickening, leukocyte infiltration, and the amount/orientation of collagen bundles. Dermal thickness and the number of alpha-smooth muscle actin (alpha-SMA)-positive cells were also determined. The quantity of the collagen-specific amino acid hydroxyproline was measured by spectrophotometry.

RESULTS

Bleomycin treatment induced marked cutaneous thickening and fibrosis compared with that observed in control mice treated with PBS. The composite sclerosis score was 18% higher, dermal thickness was 19% higher, the number of alpha-SMA-positive cells was 47% higher, and the amount of hydroxyproline was 57% higher in TRPV1(-/-) mice than in their WT counterparts. Similarly, the composite sclerosis score was 47% higher, dermal thickness was 29% higher, the number of alpha-SMA-positive cells was 76% higher, and the amount of hydroxyproline was 30% higher in CGRP(-/-) mice than in the respective WT groups.

CONCLUSION

These results suggest that activation of the TRPV1 receptor by mediators of inflammation induces sensory neuropeptide release, which might exert protective action against fibrosis. We confirmed the protective role of CGRP in the development of cutaneous sclerosis.

[The "watermelon" stomach as a rare cause of upper gastrointestinal bleeding]

The watermelon stomach is a rare subtype of the gastric vascular malformations of unknown origin. It can usually be observed with autoimmune diseases, but in can be associated with other conditions. It is significant, since it can cause chronic iron-deficiency anaemia or sometimes serious acute blood loss. The typical endoscopic picture is linear red streaking of the antrum with convergence at the pylorus with visible tortuous small vessels. Histological examination is frequently not diagnostic. It demonstrates specific features including dilated mucosal capillaries with focal thrombi, dilated submucosal venous plexus and fibromuscular hyperplasia of the lamina propria. Therapy mostly is endoscopic, but some medical possibilities are also known. In their paper they report two cases of watermelon stomach, the lesions were successfully treated with oestrogen-progesterone compounds.

Genetic instability is associated with histological transformation of follicle center lymphoma

Follicle center lymphoma (FCL) is an indolent B cell non-Hodgkin's lymphoma (NHL) characterized genetically by the t(14;18) translocation. Histological transformation and clinical progression of FCLs are frequently associated with secondary genetic alterations at both nucleic acid and chromosomal levels. To determine the type and pattern of genomic instability occurring in histological transformation of FCLs and the role of DNA mismatch repair defects in this procedure, we have performed microsatellite analysis, comparative genomic hybridization (CGH) and mutational analysis of hMLH1 and hMSH2 genes on serial biopsy specimens from patients with FCL transformed to diffuse large cell lymphoma (DLCL). Paired biopsy samples of eight patients were analyzed for microsatellite instability and structural alterations for hMLH1 and hMSH2 genes, and tumor samples of five patients were subjected to CGH analysis. A high level of microsatellite instability was associated with histological transformation of two cases of FCL, but no mutations of the hMLH1 and hMSH2 genes were detected in any of the lymphoma samples. In the five cases subjected to CGH analysis, the histological transformation of FCLs was associated with genomic imbalances at 21 chromosomal regions. The genomic abnormalities found were rather heterogeneous and none of the genetic changes were overrepresented in the transformed DLCLs. These data suggest that histological transformation of FCLs to DLCL is frequently associated with genome wide instability at both nucleic acid and chromosomal levels, although mutations of the hMSH1 and hMLH2 genes are not involved in this process.

[Detection of minimal residual diseases in B-cell tumors using PCR specific for the immunoglobulin heavy chain gene]

In B-cell non-Hodgkin's lymphomas (NHL), clonal rearrangement of the immunoglobulin heavy chain (IgH) gene provides a useful marker for the detection of minimal residual disease (MRD) after treatment. To explore clinical usefulness of polymerase chain reaction (PCR) analysis of clonal IgH gene rearrangement in the detection of MRD a follow up study of 10 patients with B-cell NHL have been performed. At the time of diagnosis, tumor DNAs were PCR-amplified using sense primer specific for the heavy chain variable region (VH) and antisense primer specific for the heavy chain joining region (JH) of the IgH gene. The clonal rearrangement of IgH gene detected by PCR was used as clonal marker to determine MRD after treatment. In three cases, where clinical remission was not achieved, clonal IgH gene rearrangement was detected after the treatment. In seven cases, clinical remission was achieved after induction therapy but the PCR analysis revealed clonal IgH gene rearrangement in three of the cases. In all of the three cases, where MRD was detected by PCR, clinical relapse developed after 7-28 months of the therapy. In all cases that have relapsed, the IgH gene rearrangement was identical at the time of initial diagnosis and at the relapse. This study demonstrates that PCR analysis of clonal IgH gene rearrangement is a useful method to monitor and detect MRD before clinical relapse.

Somatic mutation of the 5' noncoding region of the BCL-6 gene is associated with intraclonal diversity and clonal selection in histological transformation of follicular lymphoma

Follicular lymphoma (FL) is a B cell non-Hodgkin's lymphoma (NHL) that frequently displays a t(14;18) translocation. Clonal evolution and histological transformation of FL is frequently associated with the accumulation of secondary genetic alterations. It has been demonstrated that the BCL-6 gene can be altered by chromosomal rearrangements and by mutations clustering in its 5' noncoding region in a significant fraction of FL and diffuse large cell lymphoma (DLCL). To elucidate the role of the BCL-6 gene alterations in the histological transformation and clonal progression of FL, we analyzed serial biopsy specimens from 12 patients with FL. Two cases of FL showed no histological alteration in the second biopsy, and 10 cases of FL showed morphological transformation to DLCL in the second biopsy. Southern blot analysis was used to detect rearrangement of the BCL-6 gene, polymerase chain reaction-single strand conformation polymorphism and sequence analysis were performed for identification of mutations in the 5' noncoding region of the BCL-6 gene, and immunohistochemical analysis was applied to reveal the BCL-6 protein expression. No BCL-6 gene rearrangement was detected in any of the samples, but a total of 58 mutations were found in the 5' noncoding region of the BCL-6 gene in seven cases. In five cases, both the FL and the clonally related FL or DLCL, and in two cases only the DLCL samples were mutated. The mutations were identical in multiple biopsy specimens of FL that did not show morphological transformation. In six patients where FL cells underwent morphological transformation, considerable intraclonal sequence heterogeneity was observed, indicating an ongoing type of somatic mutation. Based on the pattern of shared and nonshared mutations, the genealogical relationship of neoplastic clones could be established. In all of these cases, the histological transformation of FL was associated with the emergence of a subpopulation marked by new sites of mutations in the BCL-6 5' noncoding sequences. In three of these six cases, the histological transformation is also associated with the reduced expression of the BCL-6 protein. These findings demonstrate that mutation of the 5' noncoding region of the BCL-6 gene developed in the clonal evolution of FL, and at different time points in the lymphoma evolution different clonotypes dominate.

13C-Urea breath test is superior in sensitivity to detect Helicobacter pylori infection than either antral histology or rapid urease test

There is no single technique which fulfils the criterion for a reference method to detect Helicobacter pylori (Hp) infection. The aim was to compare the results of antral histology (H), rapid urease test (U) and urea breath test (UBT) from antral biopsy samples in patients having gastric or duodenal lesions during upper GI endoscopy. We used the following methods: 1) biopsy specimens for histology (Warthin-Starry staining); 2) rapid urease test; and 3) 13C-urea breath test with infrared spectrometry. The total number of patients was 166 examined by H, U, and UBT. H, U and UBT were negative (-) in 64 patients and positive (+) in 51. The true positivity and false negativity (%, number of patients in parentheses) of each method based upon the positivity of the other two tests were: H+, U+ (54): UBT+, 94.4% (51) and UBT-, 5.6% (3); H+, UBT+ (57): U+, 89.5% (51) and U-, 10.5% (6); U+, UBT+ (65): H+, 78.5% (51) and H-, 21.5% (14). If Hp infection is considered to be positive when at least two tests detect the presence of Hp, UBT shows the highest sensitivity in comparison to histology of biopsy specimens and urease test. UBT is highly recommended as a screening test for Hp infection in patients presenting upper GI endoscopic alterations.

Immunoglobulin V(H) gene mutational analysis suggests that blastic variant of mantle cell lymphoma derives from different stages of B-cell maturation

To characterise the nature of the cellular origin of the blastic variant of mantle cell lymphoma (MCL-BV), we analysed the immunoglobulin (Ig) heavy chain variable region (V(H)) genes in four cases of MCL-BV. The rearranged V(H)-D J(H) genes were PCR-amplified, cloned and sequenced. In one case, the comparison of the rearranged V(H) gene sequence to known germline V(H) gene templates showed no somatic mutations suggesting a pre-germinal centre B-cell origin for tumour cells. In the other three cases, the V(H) gene sequences showed varied number of point mutations relative to the putative germline V(H) gene sequences but the point mutations were not associated with intraclonal diversification. In one of the mutated cases, the distribution and type of the mutations indicated that tumour cells had been selected by an antigen. Since somatically mutated Ig genes are expressed by B-cells that have reached a germinal centre/post-germinal centre stage of development, these findings suggest that the MCL-BV cell of origin may also be a germinal centre or a post-germinal centre B-cell. Taken together, our findings suggest that the development of MCL-BC may not be restricted to one stage of B-cell differentiation and that they may represent transformants of B-cells at different stages of ontogeny.

[Pathologic diagnosis of mantle cell lymphoma based on histologic, cytologic, immunohistologic and genetic characteristics]

Mantle cell lymphoma (MCL) is a clinocopathologic entity representing a broad histologic and cytologic spectrum from cystic to the blastic form. The histologic, cytologic heterogeneity of MCLs may lead to diagnostic confusion. The aim of this study was to reclassify NHLs registered as centrocytic lymphoma and centrocytoid-centroblastoma by the Lymphoma Reference Centrum at the Department of Pathology, University Medical School of Pécs between 1988 and 1995. 63 of 67 selected cases have been classified as mantle cell lymphoma according to histological, cytological appearance, and the pheno- and genotype of tumour cells. 48% of the cases showed diffuse while 52% showed nodular histological pattern. 27% of diffuse MCLs composed of classic MCL cells (small to medium-size cells) 40% blastic and 33% both small and blastic lymphoma cells. In 76% of the nodular MCLs the tumour consisted of small to medium-size cells 15% blastic while 9% both small and blastic lymphoma cells. In 99% of MCL the diagnosis was supported by CD5, CD20 and CD23 positivity and in 67% by the presence of cyclin D1-overexpression. The t(11;14) chromosome translocation PCR amplification was positive in 3 of 17 cases investigated. The authors conclude that MCLs represent a heterogeneous disease based on the cytology of the tumour cells. The nodular architecture was associated with classic MCL cells while the diffuse form was more frequently associated with blastic or combined cytological appearance. The correct diagnosis of MCL could be reached by tumour cell immunophenotyping, while molecular genetic methods proved to be informative only in part of the cases studied.

[Analysis of T-cell receptor gamma-gene rearrangement in lymphoproliferative disorders using polymerase chain reaction]

T-cell non-Hodgkin's lymphomas (NHL) exhibit a clonal T-cell receptor (TCR) gamma gene rearrangement as a result of sequential assembly of their variable (V gamma) and joining (J gamma) region segments. The analysis of the TCR gamma gene rearrangements may help to differentiate reactive lymphoproliferations from T-cell NHLs. The aim of this study was to reveal the usefulness of polymerase chain reaction (PCR) analysis of the TCR gamma gene rearrangement in the diagnosis of T-cell NHLs using native and formol-paraffin embedded tissues. The PCR amplification of the TCR gamma gene was performed by the V gamma specific sense and J gamma specific antisense primer pairs. The PCR products were evaluated by polyacrilamide gel electrophoresis containing ethidium bromide. The PCR analysis of the TCR gamma gene rearrangements has been performed in 95 lymphoproliferative disorders. The PCR analysis of the TCR gamma gene showed clonal gene rearrangement in 22 cases out of the 39 T-cell NHLs and in one case out of the 12 O-cell anaplastic large cell lymphoma but no clonal rearrangements were detected in any of the 15 reactive lymphoproliferations or 13 B-cell NHLs. Thus, clonal TCR gamma gene rearrangements was detected by PCR in 58.2% of T-cell NHLs but no clonal TCR gamma gene rearrangements were shown in any of reactive lymphoproliferations of B-cell NHLs. These studied showed that the PCR amplification of the TCR gamma gene can be a powerful tool in the diagnosis of T-cell NHLs.

Blastic transformation of mantle cell lymphoma: genetic evidence for a clonal link between the two stages of the tumour

AIMS

The blastic variant of mantle cell lymphoma (MCL-BV) may develop through histological transformation of mantle cell lymphoma (MCL). However, the clonal link between the tumour cells of MCL and transformed MCL-BV has not been established at the genetic level. To investigate this link longitudinal molecular genetic studies have been performed in two cases of MCL that showed morphological transformation to MCL-BV.

METHODS AND RESULTS

Polymerase chain reaction (PCR) and nucleotide sequence analyses of the complementary determining region 3 (CDR) of the immunoglobulin (Ig) heavy chain (H) gene were performed to identify clone-specific rearrangements. In both cases, nucleotide sequence analysis revealed common clone-specific IgH gene rearrangements in MCL and subsequent MCL-BV.

CONCLUSIONS

These results provide genetic evidence for the common clonal origin of MCL and subsequently developed MCL-BV.

[Iron deficiency anemia caused by an arteriovenous malformation in the distal ileum]

The case of a young woman with chronic iron deficiency anemia is described. Her consequent guaiac-positive stool suggested a gastrointestinal bleeding behind her anemia. The use of the conventional diagnostic techniques did not result in a definitive diagnosis. The source of the hemorrhage was later detected by the aid of selective mesenteric arteriography as an unusual form of arteriovenous malformations localized to the small intestine. 20 months passed since the resection of the affected intestinal segment. During this period of close follow up no clinical signs of recurrent gastrointestinal hemorrhage was observed. The authors briefly review the relevant literature.

[Clonality analysis of B-cell lymphoproliferative disorders by means of immunoglobulin heavy chain polymerase reaction]

The majority of B-cell non-Hodgkin's lymphomas (NHL) exhibit a highly specific immunoglobulin heavy chain (IgH) gene rearrangement as a result of sequential assembly of their Ig variable (VH), diversity (D) and joining (JH) region segments. The analyses of Ig gene rearrangements in B cells may help to differentiate reactive lymphoproliferations from NHLs, and to identify of their B-cell origin. The aim of this study was to reveal the usefulness of polymerase chain reaction analysis of the Ig gene rearrangement in the diagnosis of B-cell NHLs, using native and formol-paraffin embedded samples. The authors analysed 67 biopsy samples of immunohistochemically characterized lymph nodes diagnosed at the Department of Pathology. University Medical School of Pécs, between 1993 and 1995, using IgH gene polymerase chain reaction. The 67 samples included 10 reactive lymphoproliferations, 47 B-cell, 5 T-cell NHLs and 5 Hodgkin's diseases. In 54 cases, fresh, unfixed, in 13 cases, formalin-fixed samples have been used. The polymerase chain reaction amplification of the Ig heavy chain third complementary determining region (CDR 3) was performed by IgVH specific sense and JH specific antisense primer pairs. The polymerase chain reaction products were evaluated by agarose gel electrophoresis containing ethidium bromide. Sixty-four % of fresh, unfixed and 54% of formol-paraffin fixed B-cell NHLs samples showed clonal Ig gene rearrangement. The applied polymerase chain reaction technique did not show clonal amplification in reactive lymphoproliferations, T-cell NHLs or Hodgkin's disease. The polymerase chain reaction amplification of the IgH gene can be a powerful tool in the diagnosis of monoclonal B-cell lymphoproliferative disorders.