Assessment of distribution of CD34 epitope classes in fresh and cryopreserved peripheral blood progenitor cells and acute myeloid leukemic blasts.

BACKGROUND AND OBJECTIVE: So far several reports have described changes in the expression of surface antigens in progenitor cells and blasts following cryopreservation. However, there are no data on the effects of cryopreservation on the expression of the three CD34 epitope classes, and on their relationship with the clonogenic capacity of PBPC collected by leukapheresis. DESIGN AND METHODS: In order to analyze the effects of freezing/thawing procedures (Eth 80C storage for 3 months) and use of dimethylsulfoxide (DMSO) on the immunophenotype profile and colony production of peripheral blood progenitor cells (PBPC) in apheresis products derived from 20 patients with stage 0-III non-Hodgkin's lymphoma (nHL), a flow cytometry study was undertaken using different CD34 monoclonal antibodies (MoAbs) capable of recognizing the 3 epitope classes of CD34 molecule (class III: HPCA-2/FITC, HPCA-2/PE, 581/FITC, 581/PE; class II: Q-Bend 10/PE; class I: ICH3/PE, BI3C5-PE, Immu-133-PE). CD34 epitope expression was also analyzed in thawed CD34+ blasts obtained from 14 patients with acute myeloid leukemia (AML), who were analyzed using a larger number (#17) of CD34 epitope class I, II, and III reactive MoAbs. RESULTS: Under our experimental conditions it was found that class III and class II CD34 epitopes (differentially resistant to enzymatic cleavage with neuraminidase, chymopapain and glycoprotease) are better preserved than class I epitope Eth sensitive to degradation Eth after cell exposure to cryoprotectant DMSO and the freezing- thawing procedures. Results further showed a concomitant decrease in class I CD34+ counts and in BFU-E colony production. A significant increase in CD34 antigen expression levels (i.e. antibody binding capacity, ABC) by cryopreserved cells stained with CD34 epitope class III, and class II reactive MoAbs was also documented, while no changes after cryopreservation were noted using class I-reactive MoAbs. The slight increase in the percentage of CD34+ cells detected after frozen storage was correlated to a concomitant decrease in the number of more mature myeloid cells (CD15+, CD13+, CD33+). Compared to pre-cryopreservation values, a slight reduction in class I CD34 epitope expression was also found in thawed CD34+ AML blasts. INTERPRETATION AND CONCLUSIONS: As far as the reduction of class I CD34 epitope is concerned, it may be hypothesized that the freezing procedure, use of DMSO, and/or lysis methodology may either damage a CD34 subset, or induce distinct alterations of the CD34 glycoprotein, possibly determining a reduction in their immunoreactivity with some CD34 MoAbs. In conclusion, this study has shown that exposure to the cryoprotectant DMSO and the freezing/thawing procedures modifies the distribution of CD34 epitopes as well as the clonogenic capacity of PBPCs from nHL patients, and CD34+ blasts from AML. These findings need to considered when selecting CD34 MoAbs for enumeration and positive selection of stem/progenitor cells for research and clinical purposes.

[A case of pseudomembranous colitis in childhood]. / Osservazione di un caso di colite pseudomembranosa in età pediatrica.

"Pseudomembranous colitis" is a disease which has gained importance in the last decades. It is caused by intestinal colonization by "Clostridium Difficilis" which in normal situations, especially in the evolutive age, is a component of the normal saprophytic flora. Antibiotic therapy, or reduction of the immunological defenses by surgical procedures, infections, weakening diseases or malnutrition states may produce an alteration of the intestinal flora with a prevalence of Clostridium Difficilis which causes, with its intestinal toxin, organic and functional damages. The diagnosis is based on clinical symptoms and on endoscopic picture. The isolation of Clostridium Difficilis and its toxin in the patient's faeces is possible only in well-trained laboratories. The disease subsides with antibiotic interruption and with Vancomycin oral therapy. The Authors describe a paradigmatic case characterized by the simultaneous presence of antibiotic therapy, surgical procedure, characteristic endoscopic picture and by the prompt clinical and endoscopic recovery with Vancomycin.

[Benign intracranial hypertension during treatment with acetylsalicylic acid: presentation of 2 cases in children]. / Ipertensione endocranica benigna in corso di terapia con acido acetilsalicilico: segnalazione di due casi in età pediatrica.

The authors report two cases of benign intracranial hypertension associated to Aspirin therapy promptly regressed after withdrawal of the drug. This side effect did never described and its pathogenetic mechanism is unknown.

[Sjogren-Larsson syndrome. Description of a case]. / Sindrome di Sjogren-Larsson. Descrizione di un caso.

The authors describe a typical case of Sjogren-Larsson Syndrome showing a clear improvement of the spastic paresis after 2 years of physiotherapy and a diet rich in polyunsaturated fatty acids.

[Mixed connective tissue disease in childhood. Report of a case]. / La malattia mista del connettivo in età pediatrica. Segnalazione di un caso.

The Authors report a case of MCTD in a 11 years old girl. Initially the disease presented the classical clinical picture of IDM. Successively its evolution was marked by the appearance of the typical clinical features of JRA, SS and of serum antibodies anti-RNP and by absence of antibodies anti-dsDNA and anti-Sm. These data are characteristic of MCTD. The occurrence of this disease in children is extremely rare and the prognosis is related to a possible renal and/or haemopoietic involvement.

[Mucha-Habermann disease. Description of a case in childhood]. / La malattia di Mucha-Habermann. Descrizione di un caso in età pediatrica.

The authors report a case of Mucha-Habermann disease in childhood. Mucha-Habermann disease is not a very well known, though not infrequent, disease. It is characterized by recurrent erythematous-papular-vesicular skin lesions associated with arthralgia or arthritis or large joints. Prognosis is generally favourable although an evolution towards Pityriasis Lichenoides Chronica and/or Mycosis Fungoides is possible. There are not specific laboratory findings for this form. Diagnosis is essentially based on histology showing an immunopathogenetic vasculitis. At the present time there is not a safe therapy for the disease; there are however indications for the use of Erythromycin and we followed these in our therapy with positive results.