L. Casarino

Allogeneic hemopoietic SCT for patients with primary myelofibrosis: a predictive transplant score based on transfusion requirement, spleen size and donor type

A total of 46 patients with primary myelofibrosis (PMF) (median age 51 years), underwent an allogeneic hemopoietic SCT (HSCT) after a thiotepa-based reduced-intensity conditioning regimen. The median follow-up for surviving patients is 3.8 years. In multivariate analysis, independent unfavorable factors for survival were RBC transfusions >20, a spleen size >22 cm and an alternative donor—24 patients had 0–1 unfavorable predictors (low risk) and 22 patients had 2 or more negative predictors (high risk). The overall actuarial 5-year survival of the 46 patients is 45%. The actuarial survival of low-risk and high-risk patients is, respectively, 77 and 8% (P<0.0001); this is because of a higher TRM for high-risk patients (RR, 6.0, P=0.006) and a higher relapse-related death (RR, 7.69; P=0.001). In multivariate Cox analysis, the score maintained its predictive value (P=0.0003), even after correcting for donor–patient age and gender, Dupriez score, IPSS (International Prognostic Scoring System) score pre-transplant and splenectomy. In conclusion, PMF patients undergoing an allogeneic HSCT may be scored according to the spleen size, transfusion history and donor type; this scoring system may be useful to discuss transplant strategies.

Factors influencing haematological recovery after allogeneic haemopoietic stem cell transplants : graft-versus-host disease, donor type, cytomegalovirus infections and cell dose

Platelet recovery after allogeneic haemopoietic stem cell transplant (HSCT) and predictive factors were analysed in 342 patients with haematological malignancies. All patients were prepared with cyclophosphamide plus total body irradiation, and received an unmanipulated HSCT from an HLA‐identical sibling (n = 270), a matched unrelated donor (n = 67) or an identical twin (n = 5). The source of stem cells was peripheral blood (n = 15) or bone marrow (n = 327). Graft‐vs.‐host disease (GvHD) prophylaxis consisted of cyclosporin A with or without methotrexate. The proportion of patients with < 50 × 109/l platelets on d +50, d +100, d +200 and d +365 after HSCT was 26%, 27%, 14% and 11% respectively. Thrombocytopenia was independent of the degree of complete donor chimaerism. Four variables were predictive of platelet recovery: donor type, acute GvHD, cytomegalovirus (CMV) infection and number of cells infused at transplant. Recipients of an unrelated graft had lower platelet counts (49 × 109/l) on d +50 than identical sibling grafts (108 × 109/l) (P < 0·001) and twin grafts (149 × 109/l) (P < 0·001). Patients with GvHD grades 0, I, II, III and IV had significantly different platelet counts on d +50 (153 × 109/l, 102 × 109/l, 85 × 109/l, 32 × 109/l and 22 × 109/l; P < 0·001) and thereafter. Thrombocytopenia was more frequent in patients with high‐level CMV antigenaemia (> four positive cells/2 × 105) (P < 0·0001) and in patients who received a low cell dose at transplant (≤ 4·1 × 108/kg) (P = 0·009). Platelet counts predicted transplant‐related mortality (TRM) and were higher at all time intervals in patients surviving the transplant. Patients with grade II GvHD and > 50 × 109/l platelets had a lower TRM than patients with grade II GvHD and ≤ 50 × 109/l platelets (14% vs. 40%, P < 0·0001).

Evidence of cytogenetic and molecular remission by allogeneic cells after immunosuppressive therapy alone.

An immunosuppressive but not myeloablative regimen followed by HLA‐matched donor mobilized haemopoietic stem cell transplantation was employed in two high‐risk patients. The first patient had refractory anaemia with excess blasts (RAEB) and cytogenetic evidence of translocation 1;3(p36;q21). The second patient had Philadelphia‐negative but p190 BCR‐ABL chimaeric gene positive chronic myelogenous leukaemia in accelerated phase (AP‐CML). The conditioning regimen consisted of fludarabine (30 mg/m2/d, days 1–3) with cyclophosphamide (300 mg/m2/d, days 1–3). Cyclosporine and methotrexate were employed for acute graft‐versus‐host disease (aGVHD) prophylaxis. In both cases the engraftment of donor cells was demonstrated by cytogenetics and short tandem repeat polymorphisms via PCR. Both patients are alive with normal cytogenetic (RAEB) and molecular (AP‐CML) remissions, 100 and 150 d after allografting, respectively. In particular, in the AP‐CML patient, the BCR‐ABL became undetectable and the BCR‐ABL/ABL ratio was <0.0001.

Allogeneic bone marrow transplantation (BMT) for adults with acute lymphoblastic leukemia (ALL): predictive role of minimal residual disease monitoring on relapse.

We developed a PCR-based method to monitor clonogenic IgH VDJ rearrangement as a possible predictor of relapse in patients with acute B-ALL after allogeneic bone marrow transplantation (BMT). We studied 23 patients at diagnosis, before and after BMT. At the time of BMT, 13 patients were in first complete remission, eight in second complete remission and two in relapse. Four patients were PCR negative before BMT and remained PCR negative also after BMT (−/− pattern). They are still in remission after a median follow-up of 41 months. Nineteen patients were MRD-positive before BMT: three were PCR negative at first determination after BMT (+/− pattern) and maintain remission. Sixteen patients were PCR-positive at first determination after BMT (+/+ pattern): five became PCR negative (+/+/− pattern) (four with chronic graft-versus-host disease (GVHD) and two after donor lymphocyte infusions (DLI)). Nine patients remained PCR-positive (+/+/+ pattern) (four remain in remission, and six relapsed); two patients died before transplant. In conclusion, PCR negative patients before BMT remained negative post-BMT; many pre-BMT positive patients had initial MRD positivity after BMT: 37% of them achieved a molecular remission with cGVHD or DLI.

Inferring relationships between pairs of individuals from locus heterozygosities

BackgroundThe traditional exact method for inferring relationships between individuals from genetic data is not easily applicable in all situations that may be encountered in several fields of applied genetics. This study describes an approach that gives affordable results and is easily applicable; it is based on the probabilities that two individuals share 0, 1 or both alleles at a locus identical by state.ResultsWe show that these probabilities (zi) depend on locus heterozygosity (H), and are scarcely affected by variation of the distribution of allele frequencies. This allows us to obtain empirical curves relating zis to H for a series of common relationships, so that the likelihood ratio of a pair of relationships between any two individuals, given their genotypes at a locus, is a function of a single parameter, H. Application to large samples of mother-child and full-sib pairs shows that the statistical power of this method to infer the correct relationship is not much lower than the exact method. Analysis of a large database of STR data proves that locus heterozygosity does not vary significantly among Caucasian populations, apart from special cases, so that the likelihood ratio of the more common relationships between pairs of individuals may be obtained by looking at tabulated zi values.ConclusionsA simple method is provided, which may be used by any scientist with the help of a calculator or a spreadsheet to compute the likelihood ratios of common alternative relationships between pairs of individuals.

A ‘de novo’ point mutation of the low‐density lipoprotein receptor gene in an Italian subject with primary hypercholesterolemia

Severe hypercholesterolemia was found in an 11‐year‐old boy with no family history of familial hypercholesterolemia. The reduced LDL‐receptor activity in cultured skin fibroblasts (40%125I‐LDL degradation as compared with a control cell line) indicated the presence of an LDL‐receptor defect. The analysis of the promoter region and the exons of LDL‐receptor gene by single strand conformation polymorphism revealed an abnormal migration pattern in exon 1, which was due to a T A transversion at nucleotide 28 of the cDNA. This novel mutation causes an arginine for tryptophane substitution at position‐12 of the signal peptide (W‐12R) and introduces an AviII restriction site in exon 1. Screening of the mutation by polymerase chain reaction (PCR) amplification of exon 1 and AviII digestion revealed that none of the probands family members carried the mutation. Non‐paternity was excluded after the analysis of a battery of 14 short tandem repeats located in 13 different chromosomes. These results are consistent with the hypothesis that the proband is heterozygous for a ‘de novo’ mutation of the LDL‐receptor gene producing a non‐conservative amino acid substitution. We suggest that the change in the net charge of the signal peptide, caused by the addition of a positively charged amino acid, impairs the co‐translational translocation of the nascent receptor protein across the endoplasmic reticulum membrane.

Alternative donor transplants for patients with advanced hematologic malignancies, conditioned with thiotepa, cyclophosphamide and antithymocyte globulin

Preparative regimens without total body irradiation (TBI) have been reported for alternative donor hemopoietic stem cell transplants (HSCT). Between 7 September 1994 and 7 June 1999 48 patients with advanced hematologic malignancies were conditioned with thiotepa (THIO) 15 mg/kg, cyclophosphamide (CY) 150 mg/kg and antithymocyte globulin (ATG). Donors were HLA mismatched family members (1–2 antigens) (FAM) (n = 24, median age 31 years) or HLA matched unrelated donors (UD) (n = 24, median age 34 years). GVHD prophylaxis was cyclosporine and methotrexate. Stem cell source was peripheral blood (n = 8) or bone marrow (n = 40). Hematologic recovery was seen in 42/46 (91%) evaluable patients and complete chimerism in 31/37 patients (85%). Acute GVHD grades III–IV were seen in 10/46 patients surviving 10 days (21%) and extensive chronic GVHD in 2/36 patients surviving 100 days (5%). Twenty-six patients died (54%), eight of recurrent disease (17%) and 18 of transplant-related complications (37%): main causes of TRM were GVHD (15%), infections (15%) and graft failure (4%). Twenty-two patients (46%) survive with a median follow-up of 877 days (287–1840). The actuarial 3-year survival is 49% for FAM and 42% for UD transplants. Results obtained with this regimen in unrelated grafts for advanced CML (n = 15) were not significantly different when compared to 21 concurrent UD grafts for advanced CML prepared with CY-TBI. In conclusion, the combination of THIO-CY-ATG allows engraftment of alternative donor hemopoietic stem cells. Results are similar when using unrelated matched donors or partially mismatched family donors, and not significantly different when compared to patients conditioned with CY-TBI. Bone Marrow Transplantation (2000) 26, 1305–1311.

An unusual observation of tetragametic chimerism: forensic aspects

A 41-year-old healthy Caucasian male showed an unidentifiable direct AB0 group and a B group by an indirect method revealing the presence of natural antibodies anti-A1 and anti-A2. Mixed fields with anti-B and anti-A+B antisera led to the conclusion that blood group B and 0 cell populations were present in a 1:1 ratio. A negative anamnesis for both transplantation and transfusion suggested a chimerism. DNA analysis of tissues revealed a tetragametic chimerism due to an apparent double parental contribution of nuclei in a phenotypically normal man.

HLA-DQA1 allele and genotype frequencies in a Northern Italian population

HLA-DQA1 typing of 227 randomly selected Northern Italian people by the use of polymerase chain reaction are reported. The combined use of commercial Amplitype HLA-DQalpha system and four sequence-specific oligonucleotide probes allows the definition of 8 alleles and 36 genotypes, arranged according to World Health Organisation nomenclature. Seven of these genotypes are not observed among the analyzed samples. Allele frequencies range from 1.5 to 35.7% and genotype observations do not deviate significantly from Hardy-Weinberg equilibrium; observed heterozygosity is 0.8238 with an allelic diversity value of 0.79 and the power of discrimination is 0.925. Our Italian population sample shows differences from other Caucasian samples both for allele and genotype frequencies. This locus typing for the 8 defined alleles provides a rapid and sensitive method in individual identification and paternity investigation.

Forensic evaluation of HUMCD4: An Italian database

The YTTTC pentanucleotide short tandem repeat polymorphism HumCD4 was studied in an Italian population sample. PCR products were compared to an allelic ladder by manual PAGE and silver staining. A total of 6 alleles ranging from 5 to 12 repeats were represented in the analysed sample, of which 3 alleles (10, 6 and 5 repeats) were predominant and displayed a combined frequency of 0.91. Successful amplification was obtained from different sources such as blood and urine stains, teeth and paraffin embedded tissues. Results were also determined in cases of severely degraded DNA. We consider that the HUMCD4 polymorphism may be a useful tool for individual identification, paternity testing, population studies and have also employed this locus to monitor engraftment of bone marrow transplantation.