Variations of the perforin gene in patients with multiple sclerosis

Perforin is involved in cell-mediated cytotoxicity and mutations of its gene (PRF1) cause familial hemophagocytic lymphohistiocytosis (FLH2). PRF1 sequencing in 190 patients with multiple sclerosis and 268 controls detected two FLH2-associated variations (A91V, N252S) in both groups and six novel mutations (C999T, G1065A, G1428A, A1620G, G719A, C1069T) in patients. All together, carriers of these variations were more frequent in patients than in controls (phenotype frequency: 17 vs 9%, P=0.0166; odds ratio (OR)=2.06, 95% confidence interval (CI): 1.13-3.77). Although A91V was the most frequent variation and displayed a trend of association with multiple sclerosis (MS) in the first population of patients and controls (frequency of the 91V allele: 0.076 vs 0.043, P=0.044), we used it as a marker to confirm PRF1 involvement in MS and assessed its frequency in a second population of 966 patients and 1520 controls. Frequency of the 91V allele was significantly higher in patients than in controls also in the second population (0.075 vs 0.058%, P=0.019). In the combined cohorts of 1156 patients and 1788 controls, presence of the 91V allele in single or double dose conferred an OR=1.38 (95% CI=1.10-1.74). These data suggest that A91V and possibly other perforin variations indicate susceptibility to MS.

Familial hemophagocytic lymphohistiocytosis: how late can the onset be?

BACKGROUND AND OBJECTIVES

Most patients with familial hemophagocytic lymphohistiocytosis (HLH) develop the disease within the first two years of age. In a minority of cases a later occurrence has been reported, with an upper age limit of eight years. A significant concordance of the age at onset within each family has also been observed.

RESULTS

We report four cases of families with HLH diagnosed at an unusually late age, comprised between between 9 and 17 years; in each of these families another child developed the disease in infancy. The natural killer activity of the patients was depleted; nevertheless, we had indirect evidence that, in at least two families, mutations of the perforin gene were not causing the disease.

INTERPRETATION AND CONCLUSIONS

Such a late onset is very unusual and suggests that there is a subgroup of families with HLH in which the disease may present early or late in different members. Thus in some families with HLH the siblings might remain at risk of developing the disease for several years. Their actual risk cannot be defined until the genetic mutation is identified in each family and assessed in each member.

Hemophagocytic lymphohistiocytosis due to germline mutations in SH2D1A, the X-linked lymphoproliferative disease gene

The hemophagocytic lymphohistiocytoses (HLH) comprise a heterogeneous group of disorders characterized by dysregulated activation of T cells and macrophages. Although some patients with HLH harbor perforin gene mutations, the cause of the remaining cases is not known. The phenotype of HLH bears a strong resemblance to X-linked lymphoproliferative disease (XLP), an Epstein-Barr virus (EBV)-associated immunodeficiency resulting from defects in SH2D1A, a small SH2 domain-containing protein expressed in T lymphocytes and natural killer cells. Here it is shown that 4 of 25 male patients with HLH who were examined harbored germline SH2D1A mutations. Among these 4 patients, only 2 had family histories consistent with XLP. On the basis of these findings, it is suggested that all male patients with EBV-associated hemophagocytosis be screened for mutations in SH2D1A. Patients identified as having XLP should undergo genetic counseling, and be followed long-term for development of lymphoma and hypogammaglobulinemia.

Cytogenetic abnormalities in PHA-stimulated lymphocytes from patients with Langerhans cell histocytosis. AIEOP-Istiocitosi Group

The aetiopathogenesis of Langerhans cell histiocytosis (LCH) is still undefined. Constitutional abnormalities in LCH have rarely been reported. One study showed chromosomal instability in lesional cells from three patients. No chromosomal studies are available on peripheral blood lymphocytes. Peripheral blood lymphocytes were analysed for the presence of chromatid and/or chromosomal breaks and structural rearrangements. A fluorescence in situ hybridization (FISH) painting technique was also applied in two cases. Sixteen patients with multisystem (MS, n = 11) or single system (SS, n = 5) LCH were studied. either at the diagnosis (n = 8), during treatment (n = 2) or during follow-up, when asymptomatic (n = 6). Thirteen patients had chromosomal abnormalities. Eleven patients (69%) had chromatid and chromosomal breaks in 7-45% of cells. Overall, chromosome and chromatid breaks were significantly more frequent in the 11 patients with MS disease than in the five patients with SS disease: the mean percentage of cells showing chromosome and chromatid breaks was 13.4% in MS patients vs. 6.2% in SS patients (P = 0.003). Chromosomal abnormalities may be found in phytohaemagglutinin (PHA)-stimulated peripheral blood lymphocytes of LCH patients at diagnosis, during the disease course and even during long-term follow-up, more frequently in MS disease. Chromosome instability may be considered as either a basic genetic instability or as a landmark of reaction to an environmental agent (viral?) that, through genome alteration, may play a role in histiocyte proliferation and, in some cases, also in the increased risk of malignancy.

Hemophagocytic lymphohistiocytosis in a patient with deletion of 22q11.2

We report on a new patient with deletion of 22q11 associated with hemophagocytic lymphohistiocytosis and a fatal outcome. She had minor facial anomalies and cardiac malformation corresponding to those described in del (22q11) syndrome, normal T and B cell function and NK activity; bone marrow aspiration showed active erythrophagocytosis. Our case in addition to two other children reported previously suggest that such a rare association between lymphocyte-macrophage activation and deletion of 22q11 may be more frequent than previously recognized.

The breakpoints of a constitutional inversion of chromosome 9 associated with haemophagocytic lymphohistiocytosis are not linked to the disease gene

Haemophagocytic lymphohistiocytosis (HLH) is a severe disorder of early infancy consistent with an autosomal recessive inheritance. Neither the genetic locus nor the biochemical defect is known for the disease. A constitutional pericentric inversion of chromosome 9, with breakpoints in bands 9p23 and 9q31, has been reported in a case of HLH, suggesting a possible relationship between this chromosome abnormality and the disease. We investigated such an association, performing a genetic linkage analysis in a set of five consanguineous HLH families. 27 polymorphic markers on chromosome 9 were studied, excluding most of chromosome 9 as a putative site for the HLH gene.

Expression of p75 chain of IL-2 receptor in the early immunological reconstitution after allogeneic bone marrow transplantation

Expression of p55 and p75 chains of IL-2 receptor (IL-2R) on the surface of both T and natural killer (NK) circulating lymphocytes was investigated in 14 paediatric patients given allogeneic bone marrow transplantation (BMT) from HLA-identical sibling or partially matched family donors. IL-2-induced proliferative and cytotoxic responses were also studied and all analysis was performed within 45 days from transplant. We found that, early after transplant, the percentage of p55+ and of p75+ peripheral blood lymphocytes (PBL) was not significantly different in patients who had received HLA-identical BMT (p55+ 8.04 +/- 4.87%; p75+ 28.27 +/- 18.85%) compared with healthy controls (p55+ 7.26 +/- 6.17%; p75+ 19.42 +/- 10.49%), while recipients of T cell-depleted marrow included a remarkably high percentage (76-90%) of p75+ PBL, which were mostly CD3- and co-expressed CD56 molecule. Comparable values of p55+ lymphocytes were observed in all patients and controls. However, in contrast to the other two groups, in recipients of T cell-depleted BMT the majority of these cells co-expressed p75 chain and CD56 antigen. IL-2-induced proliferation and lymphokine-activated killer (LAK) activity were detectable in all patients, and their values did not correlate with expression of p55 or p75 chains. Our data suggest that expansion of NK subsets expressing IL-2R chains after T cell-depleted BMT may be related to early reconstitution of natural immunity in the presence of allogeneic stimuli.

Beta-endorphin, insulin, ACTH and cortisol plasma levels during oral glucose tolerance test in obesity after weight loss

In order to clarify a possible relationship between opioid peptides and glucose homeostasis in obesity we studied Beta-Endorphin (B-Ep), ACTH, cortisol and insulin plasma levels in response to an oral glucose tolerance test (OGTT) in 8 subjects after a hypocaloric diet for 90 days. We obtained through this treatment a weight loss superior to 30% of the initial weight excess (WE) compared with ideal body weight. Moreover, we compared the obtained results with our preliminary study that was performed with the same protocol but without caloric restriction. B-Ep was measured by RIA after silicic acid extraction and G75 Sephadex column chromatography. ACTH, insulin and cortisol were measured directly on plasma by an RIA method. Basal and during OGTT-induced levels of glucose, insulin, ACTH and cortisol decreased in comparison with the values obtained before diet. Conversely, B-Ep remained higher than normal both in the basal condition and during OGTT, and showed values consistently similar to those before diet. These data show that hyperinsulinemia is corrected by weight loss, while hyperbetaendorphinemia remains unchanged. Accordingly, it can be suggested that no direct relationship occurs between hyper-B-Ep-hyper-IRI in obesity. A further insight into the role of hyper-B-Ep in obesity is, thus, necessary, assuming as hypothesis that the increase in B-Ep may be a cause and not a corollary of the polymorphic aspects of obesity.

008% timolol ophthalmic solution. A minimal-effect dose in a normal volunteer model

A double-masked, randomized, placebo-controlled, rising-dose, single-dose study was undertaken to assess the effect of low concentrations of timolol maleate ophthalmic solution (0.008%, 0.025%, 0.08%, and 0.25%) on intraocular pressure and its diurnal variation in healthy, normal volunteers. A single dose of 0.008% timolol exhibits a definite but minimal-effect on intraocular pressure in this normal volunteer model, causing a significant peak mean decrease in intraocular pressure from its value immediately predose. This decrease was 1.8 mm Hg (a peak mean percent decrease of 12.8%) at 2 hours postdose compared with an increase of 0.1 mm Hg (+2.5%) during a pre-study curve due to normal diurnal variation. One drop of 0.008% solution represents a single dose of approximately 2.5 micrograms of timolol. A slight contralateral ocular hypotensive effect appears to be present for 0.25% timolol at 2 hours postdose although it just failed to reach statistical significance.