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Analysis of the effectiveness of the MSCs aministration as the second- or third-line therapy of acute GVHD (aGVHD) resistant to glucocorticosteroid treatment.The study included 35 patients who received MSCs obtained from the bone marrow of healthy donors as a treatment of steroid-resistant aGVHD. The clinical parameters of patients, MSCs cultural characteristics, the MSC expression profile for various genes including those involved in immunomodulation, expression of cells surface markers, the source of MSCs, as well as the frequency and number of MSC administrations were analyzed.Response to therapy was achieved in 74% of cases, a complete response was reached in 13 (37%) patients, partial response/clinical improvement was demonstrated in 13 (37%). This treatment was ineffective in 9 patients. The prediction of a group of patients with good response to MSC therapy turned to be impossible. The differences between the effective and ineffective for the GVHD treatment MSCs samples were found. The effective ones were characterized with a decreased total MSCs production and an increase in the main histocompatibility complex and PDL-1 antigens expression.These data allow to select optimal samples for aGVHD treatment that can improve clinical results. aGVHD treatment with MSCs has shown efficacy comparable to other treatment approaches. Given the low percentage of complications and the absence of significant adverse effects, MSC therapy seems to be one of the optimal approaches to the treatment of resistant forms of GVHD.Цель.Определение эффективности введения мезенхимных стромальных клеток (МСК) в качестве терапии 23-й линий при острой реакции трансплантат против хозяина (оРТПХ), резистентной к терапии глюкокортикостероидами. Материалы и методы.В исследование включены 35 больных, которым с целью терапии оРТПХ, резистентной к лечению, введены МСК, полученные из костного мозга здоровых доноров. Проанализированы клинические показатели пациентов, культуральные характеристики МСК, профиль экспрессии различных генов, в том числе участвующих в иммуномодуляции, экспрессия поверхностных маркеров, источник МСК, частота и количество введений МСК. Результаты.Ответ на терапию достигнут в 74% случаев, полный ответ у 13 (37%) пациентов, частичный ответ/клиническое улучшение также у 13 (37%). У 9 пациентов лечение оказалось неэффективным. Выявить группу пациентов, у которых можно прогнозировать хороший ответ на терапию с использованием МСК, не удалось. Обнаружены отличия в эффективных для лечения оРТПХ образцов МСК от неэффективных. В первых отмечены снижение суммарной клеточной продукции МСК, повышение экспрессии антигенов главного комплекса гистосовместимости и PDL-1. Заключение.Эти данные позволяют выбирать необходимые образцы для лечения оРТПХ, что может улучшить клинические результаты. Терапия оРТПХ с помощью МСК показала сопоставимую эффективность по сравнению с другими подходами лечения. Учитывая низкий процент осложнений и отсутствие значимых негативных последствий, терапия МСК представляется одним из оптимальных подходов к лечению резистентных форм оРТПХ.

Incidence, severity, and risk factors for hemorrhagic cystitis (HC) were assessed in 267 patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). HC was diagnosed in 14.6% (39 patients) within 1-139 days after allo-HSCT (median duration – 39 days). Chemotherapy-related HC was diagnosed in 4 patients only. The majority (19⁄35) of patients developed late HC of viral aetiology. Median time from a day of HC diagnosis to clinical symptoms resolution was 25 days (range: 6 to 133 days). Using a multivariate analysis, allo-HSCT from mismatched unrelated/haploidentical donor was found to be a risk factor of HC (р=0.01). The analysis also showed that 82.1% of patients with HC received cyclophosphamide as a part of conditioning regimen or +3/+4 days after allo-HSCT.

The present study involved three patients with graft failure following allogeneic hematopoietic stem cell transplantation (allo-HSCT). We obtained multipotent mesenchymal stromal cells (MSCs) from the original hematopoietic cell donors and implanted these cells in the periosteum to treat long-term bone marrow aplasia. The results showed that in all patients endogenous blood formation was recovered 2 weeks after MSC administration. Donor MSCs were found in recipient bone marrow three and 5 months following MSC implantation. Thus, our findings indicate that functional donor MSCs can persist in patient bone marrow.

Introduction. Granzyme B is a serine protease commonly found in the granules of cytotoxic lymphocytes and natural killer cells. It is secreted with the pore forming protein perforin and mediates apoptosis in target cells. Granzyme B mediated cytolysis is one of the regulatory mechanisms (together with IL-2 receptors (CD25)) by which T-regulatory cells (T-regs) influence on T-effectors cells. Despite the well-known fact that T-regs participate in pathogenesis of aGVHD and their amount after allo-HSCT inversely correlates with the probability of aGVHD incidence, data about functional status of T-regs and aGVHD is still limited. Patients and methods. Peripheral blood samples were collected in EDTA-tubes at day +30 after allo-HSCT. We use PBMC from 29 patients with hematological malignancies obtained by density gradient media. This method was used due to lymphopenia in this group of patients. Group with no aGVHD consist of 22 patients (AML=12, ALL n=5, LPD=1, CML=2, AA=1, MDS=1) after allo-HSCT n=17 from MUD, n=5 from mismatch unrelated donor. MAC conditioning regimen was used in 17 cases, 5 patients receive RIC. The group of aGVHD after day +30 include 7 patients. (AML=4, ALL n=3) after allo-HSCT from MUD (n=5), mismatch unrelated donor (n=1) and n=1 from sibling HLA-identical donor. Two patients receive MAC and 5 patients receive RIC conditioning regimen. All patients in both groups receive standard immunosuppression (MMF+CSA+ATG). All patients developed II-IV grade aGVHD (II (n=1); III (n=4); IV (n=2)) with a median time onset on day +50 (34-150). The anti-CD4-APC-Cy7, anti-CD25-APC, anti-CD127-FITC and anti-Granzyme B-PE (Becton Dickinson, USA) antibodies were used to determine T-regulatory cells population. A Bland-Altman plot (difference plot) was used in analyzing the agreement between the two different methods of T-regs assay (CD4+CD25high and CD4+CD25highCD127low) - differences were not found (p=0,942). Due to this fact in our experiments CD4+CD25high cells were identified as T-reg cells (Gregg et al., 2005). 30000 of CD4+ cells were analyzed on a BD FACSCanto II to achieve sufficient statistical power (Becton Dickinson, USA). Results. As we can see on chart 1 level of Granzyme B was higher in patients who never developed aGVHD. In accordance with chart 2 percentage of Granzyme B positive T-regs in group of patients who never developed aGVHD was 7,26±1,89% in comparison with 2,04±0,93% in group who developed aGVHD after day +30 (p=0,02*). We should note that according to our previous experiments bacterial or viral infection (e.g CMV) and HLA-disparity does not affect the level of granzyme B expression in T-regs. Using ROC- curve analysis (see Chart 3) we obtained area under curve (AUC) 0,74. Conclusion. Our data shows that Granzyme B in T-reg cells after allo-HSCT in patients with standard IST may predict aGVHD onset after day +30 with satisfactory test results (AUC=0,74, «cut-off» - 4,15%; sensitivity - 85,71%; specificity - 45,45%).). According to data of our transplant center (for 2006-2016), "granzyme B-based strategy" can help us to predict up to 47,3% of all aGVHD. Disclosures: No relevant conflicts of interest to declare. Chart 1: Example of Granzyme B expression (right; shown on horizontal axis) in T-regs (left; upper right quadrant) on day +30 after allo-HSCT in group with standard immunosuppression Chart 2: Percentage of Granzyme B positive T-reg cells in patient without aGVHD and patients who develop aGVHD after day +30. Chart 3: ROC curve analysis of Granzyme B in T-regs as predictor of aGVHD. Figure Figure. Figure Figure. Figure Figure. Disclosures No relevant conflicts of interest to declare.

Introduction Allogenic bone marrow transplantation (allo-HSCT) with high-dose, post-transplantation cyclophosphamide (CY) nowadays has become an alternative for standard immunosuppression. Many groups have shown that high dose CY after allo-HSCT selectively deplete alloreactive T effector cells and downregulate Granzyme B expression in CD8+ T and NK cells after allogeneic HSCT. Despite that fact there is no data about other T cell populations, such as Tregs and their immunosuppression abilities after post-transplant CY. We studied Granzyme B expression in Treg on day +14 after allo-HSCT with post-transplant CY and standard immunosuppression. Patients and methods. Peripheral blood samples were collected in EDTA-tubes at day +14 after allo-HSCT in patients with hematological malignancies with post-BMT-CY alone (n=8) and patients with standard immunosuppression (post-HSCT CSA, MMF or MTX at standard dose) (n=18). The anti-CD4-PE-Cy7, anti-CD25-APC, anti-CD127-FITC and anti-Granzyme B-PE (Becton Dickinson, USA) antibodies were used to determine Treg cells population as CD4+ CD25high CD127low. We did not include anti-FoxP3 antibodies as FoxP3 is not so specific in humans and particularly after allo-HSCT due to technical difficulties, several isoforms and etc. CD4- lymphocytes (certainly containing CD8+ and NK-cells population that obligatorily express granzyme B) were used as internal positive control to define population of CD4+ CD25high CD127low GranzymeB+ cells and gMFI (geometric mean fluorescence intensity). 50000 of CD4+ cells were analyzed on a BD FACSCanto II (Becton Dickinson, USA). Results. Mann-Whitney U test was used to test for differences between Granzyme B+ Treg cells after post-transplant-CY alone and in a group of standard immunosuppression. The percent of CD4+ CD25high CD127low GranzymeB+ cells among CD4+ cells at day +14 after post-transplant CY alone was statistically higher (30.1±21,9; p=0.018*) than in patients with standard immunosuppression (3,52±1,56) (see Chart 1). There is no differences in Granzyme B expression (gMFI) in CD4+ CD25high CD127low cells after post-transplant-CY (2131,8±412,7) alone and in a group of standard immunosuppression (1718,17±316,8; p=0.541). It's worth to note that probably this mechanism in combination with depletion of alloreactive T effector cells and downregulation of Granzyme B expression in CD8+ T and NK cells help to prevent aGVHD in this group of patients. Conclusion We suggest that post-transplant CY spares Granzyme B expression in Tregs in a patients with post-transplant-CY and help to prevent aGVHD development in this group of patients. Despite the fact that the analyzed group is small, obtained data is important and needs further investigation. Figure 1. Granzyme B expression in Tregs after post-transplant-CY alone and in a group of standard immunosuppression. Figure 1. Granzyme B expression in Tregs after post-transplant-CY alone and in a group of standard immunosuppression. Disclosures No relevant conflicts of interest to declare.

Introduction. Granzyme B is a serine protease commonly found in the granules of cytotoxic lymphocytes and natural killer cells. It is secreted with the pore forming protein perforin and mediates apoptosis in target cells. Granzyme B – mediated cytolysis is one of the regulatory mechanisms (together with IL-2 receptors (CD25)) by which T-regulatory cells (Tregs) influence on T-effectors cells. It is a well-known fact that Tregs participate in a pathogenesis of aGVHD and their amount after allo-HSCT inversely correlates with the probability of aGVHD incidence. No clinical data exist regarding the Granzyme B positive Tregs in this setting. Patients and methods. Peripheral blood samples were collected in EDTA-tubes at day +30, +60, +90 after allo-HSCT and at day of acute GVHD onset from 27 patients with hematological malignancies (AML=12, ALL n=12, LPD=2, MDS =1; 6 with active disease, 21 - in CR) after allo-HSCT (from matched unrelated donor n=23, from matched related donor n=4; MAC = 10, RIC=17). The anti-CD4-APC-Cy7, anti-CD25-FITC and anti-Granzyme B-PE (Becton Dickinson, USA) antibodies were used to determine T-regulatory cells population as CD4+CD25high. We did not include anti-FoxP3 antibodies as FoxP3 is not so specific in humans and particularly after allo-HSCT due to technical difficulties, several isoforms, FoxP3-positivity on activated nonregulatory CD4+ cells. CD4- lymphocytes (CD8+ and NK-cells certainly containing granzyme B) were used as internal positive control to define the percent of CD4+CD25highGranzymeB+ cells and gMFI (geometric mean fluorescence intensity) among the mononuclear cell fraction. 50000 of CD4+ cells were analyzed on a BD FACSCanto II (Becton Dickinson, USA). Results. 11 patients (42%) have developed aGVHD (II-IV) at a median time of +26 day (8 - 88) after HSCT. The percent of CD4+CD25highGranzymeB+ cells among CD4+cells at day +30 after allo-HSCT in patients who never developed aGVHD was statistically higher (9,49±2,79; p=0.003) than in patients at day of aGVHD onset (3,8±1,78). It’s worth to note that in 4 patients who did not have signs of a GVHD on day +30 but developed it later (on day +40, +45, +74, +88), the percent of CD4+CD25highGranzymeB+ cells at day +30 was as low (3,38±1,47) as at day of aGVHD onset and significantly lower (p=0.003) than in patients who never developed aGVHD, thus predicting the occurrence of aGVHD in the future. Conclusion Despite the fact that the analyzed group is small, we suggest that low relative amount of CD4+CD25highGranzymeB+ cells after allo-HSCT may contribute to the development aGVHD and even predict it onset. This fact, of course, needs further investigation. Disclosures No relevant conflicts of interest to declare.