Serum HLA Research Articles

A Novel ELISPOT Assay to Quantify HLA-Specific B Cells in HLA-Immunized Individuals

Quantification of the humoral alloimmune response is generally achieved by measuring serum HLA antibodies, which provides no information about the cells involved in the humoral immune response. Therefore, we have developed an HLA-specific B cell ELISPOT assay allowing for quantification of B cells producing HLA antibodies. Enriched peripheral B cells were pre-activated in a CD40L-driven fashion before being assayed by the HLA-specific B cell ELISPOT assay. We used recombinant HLA monomers as target in the ELISPOT assay. Validation was performed with human B cell hybridomas producing HLA antibodies of defined specificity. Subsequently, we quantified B cells producing HLA antibodies in HLA-immunized individuals, non HLA-immunized individuals and transplant patients with serum HLA antibodies. B cell hybridomas exclusively formed spots against HLA molecules of corresponding specificity with the sensitivity similar to that found in total IgG ELISPOT assays. HLA immunized healthy individuals showed up to 182 HLA-specific B cells per million total B cells while non-immunized individuals had none (Figure 1). Specificities that can currently be tested in the HLA-specific ELISPOT include HLA-A1, HLA-A2, HLA-B7 and HLA-B44. The assay is highly reproducible, as determined by repeat testing of B cells from a single bleeding date.Figure 1. HLA-specific B cells are detected in HLA-immunized individuals, but not in non-immunized individuals. (A) Raw ELISPOT data of 2 HLA-A2 immunized and 2 non-immunized individuals. Frequency is the number of spots per million B cells. Enriched B cells were activated for 7 days and seeded into ELISPOT plates coated with monomeric HLA molecules (B). Frequencies of HLA-A2 specific antibody producing B cells of HLA-A2 immunized and non-immunized healthy individualsTransplant recipients who were immunized by an HLA-mismatched graft had up to 143 HLA-specific B cells per million total B cells. Moreover, preliminary data suggest that immunosuppressive drugs do not interfere with the detection of HLA-specific B cells. In conclusion, we have developed and validated a highly specific, reproducible and sensitive HLA-specific B cell ELISPOT assay, can be used to determine the frequency of peripheral HLA-specific B cells in transplant recipients. This technique constitutes a new tool for quantifying humoral immune responses.

Imaging manifestations and its clinical significance in patients with synovitis acne pustulosis hyperostosis osteomyelitis syndrome

Objective To describe the clinical and imaging manifestations of patients with synovitis acne pustulosis hyperostosis osteomyelitis (SAPHO) syndrome,and to analyze the diagnostic importance of different clinical and imaging manifestations for SAPHO syndrome. Methods Seventeen patients (7 males and 10 females) with SAPHO syndrome were recruited in this study.Age ranged from 36 to 67 years with a mean age of (48 ± 8) years. All patients fulfilled the diagnostic criteria of Benhamou. Serum HLA B27 antigen records were reviewed for all patients. Imaging data of the abnormal bone sites were collected by conventional radiograph in all patients,CT in 13 patients as well as MR in 3 patients.Average time to take for a definite diagnosis of the syndrome was 3.7 years (ranged from O.5 to 13 years).Results Serum HLA B27 antigen was positive in all patients. Both skin and bone abnornalities were found in all patients.Ten patients had skin palmoplantar pustulosis and two patients had acne. Involving sites of bone and joints include sacroiliac joints,anterior chest and limbs.Sacroiliac joints were asymmetrically involved with imaging features in all patients.Eight patients exhibited anterior chest wall involvement. Five patients had osteomyelitis at limbs. For all images of 17 patients,CT was superior to conventional radiography in detecting abnormal changes of bone erosion and soft tissue swelling.MR imaging was able to depict edema changes that was not detectable by CT and radiography.Conclusion SAPHO syndrome is a rare disease,but for patients with skin and bone-joint abnormalities,especially with skin palmoplantar pustulosis,acne as well as with imaging features at the sacroiliac joint and anterior chest wall,SAPHO syndrome should be taken into a diagnostic consideration. Key words: Acquired hyperostosis syndrome; Magnetic resonance imaging; Tomography,X-ray computed

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Aim Presence of anti-donor HLA antibodues is a contraindication to transplantation in most solid organs. In contrast, most patients with high titer donor specific antibodies (DSA) and positive flow cytometric crossmatch (FCXM) still undergo liver transplantation. Antibody mediated rejection (AMR) may or may not develop after liver transplantation in such patients. We speculated that despite positive crossmatch results, cytotoxic function of existing and/or de novo DSA is what will ultimately predict development of AMR. Methods In this study we report two conflicting cases of liver transplant patients with high titer pre-transplant DSA and positive FCXM. Pre-transplant sera of patient A and B were retrospectively tested with a C1q assay to determine the cytotoxic function of DSAs. Results One patient (patient A) developed hyperacute AMR shortly after transplantation while the second patient (patient B) did not develop any signs of AMR and her post-transplant period was uneventful. In patient A, shortly after transplantation, serum amino transaminase and bilirubin levels became elevated. Serum HLA antibody testing showed high levels of class I and class II DSAs that resulted in positive T and B cell FCXM. Positive C4d staining of liver allograft biopsy indicated an episode of AMR. Patient was treated with plasmapheresis (days 1-9), Rituximab and IVIG (days 9-13) and Thymoglobulin (days 2-8). Levels of DSA and positive FCXM decreased overtime and 4 years post-transplant DSA antibodies were no longer present. In contrast, patient B did not develop any signs of post-transplant complications related to presence of HLA antibodies. Consistent with our hypothesis at the time of transplant, DSA of patient A were positive for C1q factor. In contrast C1q was negative on DSA of patient B. Conclusions We conclude that pre-transplant antibody testing and C1q assay should be considered as pre-transplant tests to be performed to liver transplant patients. Larger studies should be performed to confirm our findings.

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Aim Expeditious flow cytometry crossmatch (FCXM) assay giving consistent inert-lab results is critical for successful and safe national organ sharing. In order to understand the degree and nature of variability in FCXM testing across Canada, national proficiency testing (PT) program was established. In the 1st PT survey, the focus was on studying the factors that contribute to FCXM result variability. The 2nd survey examined the effects of assay standardization and optimization. Methods Both surveys consisted of 3 sera, 2 donor cells and MESF beads. Donor HLA typing and serum HLA antibody profiles were provided to aid XM interpretation. Questionnaire was sent to obtain specific protocol information. XM data (channel & MESF values) and questionnaire responses were collected from 13 participating labs and analyzed. In survey 1, labs were asked to perform FCXM as per local lab protocol. In survey 2, labs were provided with optimized FCXM protocol (Liwski et al. ASHI 2011), pronase/DNase procedure and common reagents (pronase, DNase, & anti-IgG-FITC). Labs were asked to test FCXM using their own protocols with specific modifications vs optimized FCXM protocol. Results In survey 1, significant inter-lab FCXM result variability was seen. MESF scale was helpful in result comparison. Technique, cell number and serum volume were main factors contributing to observed variation. Pronase use was critical for B cell XM. In PT part 2, the findings showed that standardization (cell number/serum volume and pronase use) significantly improved result consistency. Use of optimized protocol and common α-IgG-FITC further improved results. Optimized assay compared favourably with conventional methods, while decreasing XM time by 1 h. Conclusions Significant variability in FCXM methods and results were seen. Standardization of FCXM protocol improved result concordance. Optimized FCXM protocol will improve risk assessment precision, facilitate equitable national organ sharing and optimize low risk transplant allocation.

A Novel ELISPOT Assay to Quantify HLA-Specific B Cells in HLA-Immunized Individuals

Quantification of the humoral alloimmune response is generally achieved by measuring serum HLA antibodies, which provides no information about the cells involved in the humoral immune response. Therefore, we have developed an HLA-specific B-cell ELISPOT assay allowing for quantification of B cells producing HLA antibodies. We used recombinant HLA monomers as target in the ELISPOT assay. Validation was performed with human B-cell hybridomas producing HLA antibodies. Subsequently, we quantified B cells producing HLA antibodies in HLA-immunized individuals, non-HLA-immunized individuals and transplant patients with serum HLA antibodies. B-cell hybridomas exclusively formed spots against HLA molecules of corresponding specificity with the sensitivity similar to that found in total IgG ELISPOT assays. HLA-immunized healthy individuals showed up to 182 HLA-specific B cells per million total B cells while nonimmunized individuals had none. Patients who were immunized by an HLA-A2-mismatched graft had up to 143 HLA-A2-specific B cells per million total B cells. In conclusion, we have developed and validated a highly specific and sensitive HLA-specific B-cell ELISPOT assay, which needs further validation in a larger series of transplant patients. This technique constitutes a new tool for quantifying humoral immune responses.

Associated autoimmune diseases in patients with multifocal motor neuropathy and their family members

Multifocal motor neuropathy (MMN) is a rare immune-mediated disorder and is characterized by male predominance, the presence of serum anti-GM1 IgM antibodies in up to half of all patients, responsiveness to intravenous immunoglobulins (IVIg) and an increased frequency of HLA type HLA-DRB1*15. The aim of this study was to assess whether the frequency of autoimmune diseases (AID) is increased in patients with MMN and their first-degree family members, since this would indicate that MMN shares pathogenic mechanisms with other AID. We conducted a case–control study using questionnaires to evaluate the prevalence of AID in MMN and controls, and their first-degree relatives. Questionnaires from 81 MMN patients (417 first-degree relatives) and 438 controls (2,377 first-degree relatives) were analyzed. Overall prevalence of AID was higher in MMN patients (11%) than in controls (5%) (OR 2.4, 95% CI 1.1–5.5, p = 0.037). Type 1 diabetes, Hashimoto’s thyroid disease, and celiac disease were significantly more prevalent in family members of patients than controls. The presence of an additional AID was not associated with age at MMN onset, disease duration, titer of serum anti-GM1 IgM antibodies or HLA type HLA-DRB1*15. The higher frequency of AID in patients with MMN indicates a common autoimmune diathesis.

Association of tumor necrosis factor alpha-308 promoter polymorphism with spondyloarthritides patients in Colombia

The pathogenesis of SpA is considered to be a complex and multi-factorial process and, similar to other autoimmune diseases, includes the activity of proinflammatory cytokines such as TNF alpha. Our study compared the -308 promoter polymorphism of TNF alpha with TNF alpha levels, HLA-B27 status, age at the onset of symptoms, SpA subtype and the clinical degree of activity in Colombian SpA patients and healthy subjects (HS). Comparisons of the TNF alpha-308A genotype among HS and SpA patients (P = 0.004), uSpA patients (P = 0.040), ReA patients (P = 0.001), were significantly different and AS patients (P = 0.110), as were alleles for SpAs (P = 0.007) between patients with SpAs and controls. Initial exploratory analyses demonstrated that the TNF alpha-308 SNP genotype frequencies were different among SpA patients and HS in the Colombian population studied. Furthermore, there was no significant correlation with activity and functional clinical index, serum TNF alpha level or HLA B27 status. Allele frequencies, on the other hand, were correlated with the activity clinical index.

Effective and ineffective personalized therapy based on serum HLA from a 30-year odyssey

Effective and ineffective personalized therapy based on serum HLA from a 30-year odyssey

Peripheral blood B cells producing donor-specific HLA antibodies in vitro

Donor-specific HLA antibodies have been associated with acute and chronic rejection. Such antibodies may sometimes not be detected in recipient serum. In an attempt to learn about possible mechanisms, we investigated antibody production by recipient B lymphocytes in vitro. Peripheral blood B cells were obtained from 36 subjects, including 16 allograft recipients, 12 sensitized patients, three multiparous women with serum HLA antibodies, and five healthy non-transfused male subjects. Purified B cells were cultured with a cell line expressing CD40 ligand. Culture supernatants were screened for HLA antibodies, and positive samples were analyzed using single antigen beads to determine antibody specificity. HLA antibody–producing B cells were detected in persons known to be sensitized. In 13 of 16 allograft recipients, IgG antibodies against mismatched donor HLA antigens were observed, and donor-specific antibodies were sometimes produced in B-cell cultures when serum reactions were negative. IgM antibodies against HLA antigens were also identified in cultures from some transplant recipients. In two patients tested, the majority of antibody-producing B cells developed from CD27 + memory B cells. Our results suggest that analysis of B cells producing antibodies specific for donor antigens may be a useful tool for identifying and monitoring the humoral immune response in organ transplant recipients.

Human B cells producing allograft‐specific HLA antibodies

Development of donor‐specific HLA antibodies following organ transplantation is associated with acute and chronic rejection. This experiment was designed to investigate recipient B lymphocytes to determine whether HLA antibodies can be produced in vitro. The method is based on culturing peripheral blood B cells stimulated by a cell line expressing CD40 ligand. Purified B cells were obtained from 26 subjects: 13 allograft recipients, 9 sensitized patients on the transplant waiting list, 2 multiparous women with serum HLA antibodies, and 2 healthy non‐transfused males. The culture supernatants were screened for antibodies with Luminex flow cytometry beads coupled with multiple HLA class I or class II antigens. Supernatants with antibodies were further analyzed using single antigen‐coupled beads to determine antibody specificity. Results showed that HLA antibody‐producing B cells were detected in persons known to be sensitized. In 10 of 13 allograft recipients, antibodies against mismatched donor HLA antigens were observed. In two patients we found donor‐specific antibodies produced in B cell cultures when serum reactions were negative. Our results suggest that analysis of supernatants of CD40 ligand‐stimulated B cells using Luminex single antigen HLA beads may be a useful tool for identifying and monitoring the donor‐specific humoral immune response in organ transplant recipients.

Actinic prurigo deterioration due to degradation of DermaGard�window film

Conflicts of interest: none declared. Sir, DermaGard® is a transparent polyester film with adhesive backing which can be applied to car and home window glass. It absorbs almost all ultraviolet (UV) A and UVB wavelengths (280–400 nm) while allowing visible light transmission (400–700 nm). It is useful for patients with photosensitivity disorders to reduce exposure to UVA and UVB wavelengths, of which the transmission through glass is increasing with time, due to modern glass manufacturing processes creating purer products. We are unaware of literature reports of activation of photodermatoses attributable to failure of such UV‐opaque window film and present a patient who highlights the need for awareness of its gradual loss of UV‐photoprotective properties. A 10‐year‐old boy presented with a 3‐year history of an immediate erythema on exposure to direct or window glass‐transmitted sunlight, followed by a pruritic papular eruption lasting several weeks. Although worse in summer months, the eruption was perennial, affecting both photoexposed and covered sites. Monochromator testing revealed normal immediate and delayed responses to UVB, UVA and visible light. Photoprovocation testing with a blue light UVA source using a dose of 25 J cm−2 to the forearm on two consecutive days produced an erythemal papular response, and serum HLA typing showed DR4 (subtype DRB 0407). A diagnosis of actinic prurigo (AP) was made.

Bullous pemphigoid antigen II (BP180) and its soluble extracellular domains are major autoantigens in mucous membrane pemphigoid: the pathogenic relevance to HLA class II alleles and disease severity

Mucous membrane pemphigoid (MMP), a chronic autoimmune subepithelial blistering disease, is associated with circulating IgG and/or IgA autoantibodies against several basement membrane zone antigens. The heterogeneity of clinical presentation and diversity of target autoantigens have contributed to difficulties in characterizing this condition immunologically. To analyse serum autoantibody profile and HLA class II alleles in MMP patients and to correlate this with the clinical presentation of disease. Well-defined subgroups consisting of 124 patients with MMP were examined for IgG and IgA reactivity with immunoblotting using human epidermal, dermal and placental amnion proteins. The results were further analysed on the basis of detailed clinical (sites of involvement and disease severity) and immunopathological criteria (immunofluorescence study and HLA class II alleles). Immunoblot assay revealed that the majority of MMP patients had IgG (93 of 124, 75%) and/or IgA autoantibodies (63 of 124, 51%) to BP180 (including its soluble ectodomains, 120-kDa LAD-1 and 97-kDa LABD97 antigens). Other antigens targeted predominantly by IgG autoantibodies included: BP230 in 34 (27%), beta4 integrin in 26 (21%), and laminin 5 in three (2%). All the BP230+ sera and 23 (88%) beta4 integrin+ sera also reacted with at least one of the BP180 antigens. Over 85% of patients with reactivity to beta4 integrin had ocular involvement. In most cases of MMP, more severe clinical features were associated with antibody reactivity to multiple basement membrane zone antigens, as well as reactivity to multiple BP180 component antigens. Dual BP180/LAD-1 reactivity with IgG and IgA was associated with a more severe phenotype. In addition, the subset-dependent autoantibody reactivity correlated well with specific HLA class II alleles, DQB1*0301, DRB1*04 and DRB1*11. Our results confirmed that BP180 is a major autoantigen targeted by the sera of patients with MMP. The disease-prevalent HLA class II alleles and humoral autoimmune response against the particular subsets of antigenic epitope(s) within BP180 ectodomain may contribute to the clinicopathological significance and disease severity of MMP.

Impact of Peptides on the Recognition of HLA Class I Molecules by Human HLA Antibodies

MHC class I molecules expressed on cell surfaces are composed of H chain, beta2-microglobulin and any of a vast array of peptides. The role of peptide in the recognition of HLA class I by serum HLA Abs is unknown. In this study, the solid-phase assay of a series (n = 11) of HLA-A2-reactive, pregnancy-induced, human mAbs on a panel (n = 12) of recombinant monomeric HLA-A2 molecules, each containing a single peptide, revealed peptide selectivity of the mAbs. The flow cytometry membrane staining intensities on the HLA-A2-transduced cell line K562, caused by these mAbs, correlated with the number of monomer species detected by the mAbs. Flow cytometry staining on HLA-A2-bearing cell lines of a variety of lineages was indicative of tissue selectivity of these HLA-A2 mAbs. This tissue selectivity suggests that the deleterious effect on allografts is confined to alloantibodies recognizing only HLA class I loaded with peptides that are derived from tissue-specific and household proteins. Since Abs that are only reactive with HLA loaded with irrelevant peptides are expected to be harmless toward allografts, the practice of HLA Ab determination on lymphocyte-derived HLA deserves reconsideration.

Changes in serum levels of Total protein , Albumin and Globulin in patients with Behcet's Disease.

In order to have an idea about some of biochemical changes which might play a role in the pathogenesis of Behcet's disease. Estimation of serum total protein, albumin, globulin and HLA typing were carried out in 70 patients with Behcets disease using colorematric, mathematic & microlymphocytotoxicity tests respectively, compared with 35 patients with recurrent oral ulcers, and 35 healthy control group.Hyperproteinemia, hyperglobulinemia with hypoalbuminemia were observed in those patients in comparison to control groups

Dicentric Chromosome 3 Associated with Binucleated Lymphocytes in Atypical B-cell Chronic Lymphoproliferative Disorder

Binucleated lymphocytes on blood smear are known in PPBL characterized by stable and polyclonal lymphocytosis, polyclonal increase of serum IgM, HLA DR7 and strong correlation with additional i(3q) and premature chromosome condensation. In this disorder some reports of clonal Ig rearrangement suggest a follow up of these patients with immunological and genetic studies. Binucleated lymphocytes are rarely described in other clonal B-CLPD as B-CLL or marginal zone B-cell lymphoma (MZL). Chromosome 3 abnormality is never described in B-CLL but trisomy 3 represents the most consistent abnormality characterizing the MZL. We report in a man without previous medical history an unusual B-CLPD with monoclonal lymphocytosis CD5 m, characteristic cytology (particularly binucleated lymphocytes) and chromosomic abnormality as dicentric chromosome 3 never previously described in B-CLPD. In this case lymphocytosis is persistent and stable over 24 months, cytologic immunologic and chromosomic abnormalities are unchanged. We discuss the nosologic place of this atypical B-CLPD closely related to PPBL and MZL with at the moment, after 24 months, a quiet evolution that imply nevertheless a careful follow up with regular cytologic, immunological and genetic studies to clarify the issue.

Conversion from azathioprine [correction of azathioprina] to mycophenolate mofetil in pediatric renal transplant recipients with chronic rejection.

Chronic rejection is the leading cause of graft failure. Both nonimmunological and immunological mechanisms contribute to this pathology. We studied changes in kidney function, mixed lymphocyte culture, cell-mediated lympholysis, serum HLA class I antigens, cytotoxic antibodies, and lymphocyte population before and after 6 months of follow-up in 22 pediatric renal transplanted patients. The immunosuppressive protocol used was: cyclosporine, azathioprine, and corticosteroids. Eight patients demonstrated chronic graft rejection (by biopsy), group I; and eight patients had no clinical evidence of chronic and/or acute rejection, group II. Substitution of mycophenolate mofetil (MMF) (600 mg/m2 bid for azathioprine was done in patients of groups I and II. Another six patients with chronic rejection, did not receive MMF, group III. Creatinine clearance increased in group I (44+/-5 vs. 51.1+/- ml/min/1.73 m2, P<0.03) but it decreased in group III (30+/-3 vs. 25+/-2, P<0.01). Urinary protein excretion decreased only in group I (0.3+/-0.03 to 0.06+/-0.03 g/24 hr, P<0.03). During MMF therapy antidonor mixed lymphocyte culture decreased 62 and 70% (P<0.05) in group I and II. Cell-mediated lympholysis against lymphocyte of the donor decreased 65% (P<0.05) in group I. Cell-mediated lympholysis toward control cells decreased 54% (P<0.01) in group II. Serum HLA class I antigens, only decreased from 0.7+/-0.1 to 0.5+/-0.1 microl/ml, P<0.05, in group I. CD19+ decreased from 7.9+/-1.1 to 5.6+/-0.8%, P<0.05, and 7.8+/-1.2 to 5.5+/-0.9%, P<0.05, in groups I and II, respectively. CD16+ increased from 5.7+/-1.1 to 8.6+/-1.3 (P<0.05) only in group I. Our data suggest that substituting MMF for azathioprine therapy leads to an improvement in the immunosuppression and renal function in children with on-going chronic rejection.

Abstracts of Literature.

Abstracts of Literature.

Predictors of lymphoma development in primary Sjögren's syndrome

Objective: To determine the clinical and laboratory predictors of lymphoma development in primary Sjögren's syndrome (pSS). Methods: Seventy-two patients with pSS were studied. Demographic data, clinical features, serum gamma-globulin levels, autoantibodies, and HLA status were reviewed. For statistical analysis, Mann-Whitney U-test, Fisher's exact test, logistic regression analysis, Kaplan-Meier method, and log-rank tests were applied. Results: Five patients developed a distinct non-Hodgkin's lymphoma of mucosa-associatedlymphoid tissue (MALT). A history of swollen salivary glands, lymphadenopathy, and leg ulcers predicted lymphoma development. Conclusion: Patients with pSS are at increased risk of lymphoma development, and those who have the above risk factors must be carefully observed.

Increased level of serum HLA class I antigens in patients with systemic lupus erythematosus. Correlation with disease activity

The level of soluble beta2-mu-associated HLA Class I heavy chains (sHLA-I) and of soluble beta2-mu-free HLA Class I heavy chains (sHLA-FHC) was found to be significantly higher in sera from 58 patients with systemic lupus erythematosus (SLE) than in those from 82 age and sex-matched controls. The level of serum sHLA-I in patients with SLE was significantly correlated to disease activity. Western blotting analysis showed that the 44-kDa isoform represents the major component in the antigens immunoprecipitated by anti-beta2-mu mAb NAMB-1 and by anti-beta2-mu-free HLA Class I heavy chain mAb HC-10 from sera of patients with SLE. These results suggest that the increased serum levels of sHLA-I and of sHLA-FHC in patients with SLE reflect their increased shedding from cell membrane. In view of the ability of sHLA-I and of sHLA-FHC to induce apoptosis of activated T cells, it is suggested that their increased serum levels in patients with SLE is triggered by dysregulation of the immune system leading to T-cell activation. The increased serum levels of sHLA-I and of sHLA-FHC may be used by the immune system to control the pool of activated T cells by inducing apoptosis. If this possibility is proven to be correct, modulation of the serum level of sHLA-I and of sHLA-FHC may be utilized to develop strategies to treat SLE.

Increased Soluble Serum HLA Class I Antigens in Patients with Lymphoma

ABSTRACT: sHLA are soluble forms of class I histocompatibility antigens detected in human serum and cerebrospinal fluid. These molecules are secreted by B and T lymphocytes and the secretion increases dramatically upon mitogenic activation of these cells. sHLA was quantified by an ELISA sandwich method in sera from healthy blood donors, and from patients with Non Hodgkin’s Lymphoma (NHL) and Hodgkin’s Disease (HD) both at diagnosis and at remission. Pretreatment sHLA serum levels in NHL and in HD were compared with the values found in controls. sHLA levels are increased in patients with NHL (low grade: 6.68 ± 1.80; high grade: 2.65 ± 0.53 μg/ml X ± S.E.) and HD (6.44 ± 0.98) at diagnosis and in relapses when compared with controls (0.89 ± 0.08). This increment is statistically significant (low grade NHL: p = 0.0038; high grade NHL: p = 0.0049 and HD: p = 0.0005 versus control group). No statistical differences between titers of sHLA after complete remission and sHLA in the control group were found. The high levels of sHLA detected in patients with lymphoma are mainly due to low molecular weight HLA molecules (55 KD) (60–75% of the HLA present in serum in the control group and 75–100% in serum of patients with lymphoma).