Transient depletion of innate immunity in varicella infections in otherwise healthy children

Objective: Varicella is a common childhood infection and has a number of complications in the unvaccinated population. Perforin, found in natural killer cells, is important for the killing of virally infected cells. For this reason, the aim of this study was to determine natural killer cell count and activity, perforin expression, and Fas and soluble Fas ligand (sFas-L) levels in immunocompetent children with varicella infection and define any possible relations between the levels and varicella complications. Material and Methods: Forty children were analyzed at diagnosis and on the 15th day of varicella infection. There was a significant difference in hemoglobin levels and leukocyte and platelet counts between days 0 and 15.Results: Thirteen (32%) patients were found to be lymphopenic. Natural killer cell count and activity were significantly higher on day 15 when compared to values at diagnosis. The Fas-mediated apoptotic pathway was found to be active in acute varicella infection because Fas and sFas-L levels at diagnosis were higher than values on day 15. Conclusion: These findings suggest that the Fas and Fas-L apoptotic pathway is active during the acute phase of the viral infection and that it becomes inactive by day 15, paralleling the hematologic recovery

Spectrum of Perforin Gene Mutations in Familial Hemophagocytic Lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive disease of early childhood characterized by nonmalignant accumulation and multivisceral infiltration of activated T lymphocytes and histiocytes (macrophages). Cytotoxic T and natural killer (NK) cell activity is markedly reduced or absent in these patients, and mutations in a lytic granule constituent, perforin, were recently identified in a number of FHL individuals. Here, we report a comprehensive survey of 34 additional patients with FHL for mutations in the coding region of the perforin gene and the relative frequency of perforin mutations in FHL. Perforin mutations were identified in 7 of the 34 families investigated. Six children were homozygous for the mutations, and one patient was a compound heterozygote. Four novel mutations were detected: one nonsense, two missense, and one deletion of one amino acid. In four families, a previously reported mutation at codon 374, causing a premature stop codon, was identified, and, therefore, this is the most common perforin mutation identified so far in FHL patients. We found perforin mutations in 20% of all FHL patients investigated (7/34), with a somewhat higher prevalence, ∼30% (6/20), in children whose parents originated from Turkey. No other correlation between the type of mutation and the phenotype of the patients was evident from the present study. Our combined results from mutational analysis of 34 families and linkage analysis of a subset of consanguineous families indicate that perforin mutations account for 20%–40% of the FHL cases and the FHL 1 locus on chromosome 9 for ∼10%, whereas the major part of the FHL cases are caused by mutations in not-yet-identified genes

Perforin geninde A91V frekansı ve tümör nekrozis-? faktör promotor polimorfizminin edinsel hemofagositik lenfohistiositoza etkisi

Amaç: Edinsel hemofagositik lenfohistiositozun (EHL) gelişmesinde enfeksiyonlar, habis hastalıklar, kollajen doku hastalıkları gibi çok çeşitli etmen rol oynamaktadır. Aynı tetikleyici faktörü bulunan hastaların tümünde EHL’un gelişmemesi EHL’ye yatkınlık yapan ek genetik ve çevresel faktörlerin varlığına işaret etmektedir. Yöntem ve Gereçler: Perforin geninde A91V yanlış anlam değişikliği (perforin geninde ekzon 2, pozisyon 272’de C>T değişikliği) ve tumor nekrozis faktör (TNF)-? geninin promoter bölgesinde –1031T>C nükleotid değişikliği inflamatuvar yanıtı değiştirebilen ve bu nedenle EHL’ye yatkınlığa neden olabilen iki potansiyel adaydır. Çalışmamızda EHL’li hastalar ve kontrollerde bu değişiklikler incelenmiştir. Bulgular: 159 sağlıklı Türk popülasyonunda A91V değişikliği 7 (%4.4) kişide saptanmıştır. 44 EHL olgusunun beşinde (%11.3) bu değişiklik saptanmış olup, fark dikkat çekici olmakla birlikte istatistik- sel anlamlılık göstermemiştir (p=0.09); odds oranı 2.8 olarak hesaplanmıştır. A91V pozitif olan hastaların tümünde enfeksiyon altta yatan etiolojik nedendi. TNF-? -1031T>C polimorfizmi 164 sağlıklı birey ve 40 EHL’li hastada çalışıldı. Kontrollerin 7’sinde (%4.3) ve EHL bulunan hastaların 1’inde (%2.5) riski artıran CC genotipi saptandı. C ve T allel frekansları sırasıyla EHL’de 18 (%22.5) ve 62 (%77.5), kontrollerde 72 (%22) ve 259 (%78) olarak bulundu. Allel frekansları açısından gruplar arasında fark saptanmadı (p>0.05). Sonuçlar: Çalışmamızın sonuçları edinsel HLH’li hastalarda sağlıklı kontrollara göre A91V sıklığının 2.8 kat odds oranına göre daha sık olduğunu, A91V’nin sağlıklı Türk populasyonunda nadir olmadığını ve özellikle enfeksiyonu olanlarda EHL’ye yatkınlık yapabileceğini göstermektedir.Objective: Numerous acquired etiological factors, such as infections, malignancies, and collagen tissue disorders, are involved in the development of acquired hemophagocytic lymphohistiocytosis (AHLH). Not everyone with the same etiological factors developments AHLH, which suggests the role of addi- tional genetic or environmental predisposing factors that remain to be identified. Materials and Methods: Perforin gene A91V missense transition (C>T change at position 272 in exon 2 of the perforin gene) and TNF-α gene promoter-1031 T>C nucleotide substitution are 2 candidate genetic predisposing factors due to their potential to alter inflammatory responses. In the present study these changes were investigated in healthy controls and AHLH patients. Results: A91V transition was observed in 7 of the 159 (4.4%) controls. Among the 44 AHLH patients, 5 (11.3%) were heterozygous and the difference in the frequency of A91V transition, although striking (odds ratio: 2.8), was not statistically significant (p=0.09). All A91V-positive patients had infection. TNF-α-1031 T>C polymorphism was examined in 164 healthy controls and 40 AHLH patients, and the CC risk-elevating genotype was noted in 7 (4.3%) of the controls and 1 (2.5%) of the AHLH patients. The frequency of C and T alleles was 22.5% (n=18) and 77.5% (n=62) among the AHLH patients, and 22% (n=72) and 78% (n=259) among the controls, respectively. There wasn’t a statisti- cally significant difference between the groups in terms of allele frequencies (p>0.05). Conclusion: The present results indicate that compared to controls, A91V mutation was 2.8-fold more prevalent (according to the odds ratio) in the AHLH patients. A91V mutation is not uncommon in the general population and increases the risk of AHLH in patients with an underlying condition, espe- cially those with an underlying infection

Compound heterozygosity for hemoglobin knossos [α 2β 2 27 (B9) Ala-Ser] and IVS I-1 MUTATION

A three-year-old female with compound heterozygosity for Hb Knossos and IVS-I-1 mutation is presented. On physical examination she had no abnormality except for pallor. Hb was 6.9 g/dl, MCV 61 fl, Hb A2 2% and Hb F 38.5%. Acrylamidegel electrophoresis at a pH of 6 revealed the presence of Hb Knossos in the child and her father. DNA studies revealed that the child was compound heterozygous for Hb Knossos and the IVS I-1 mutation. When the clinical expression of this combination in a previously reported patient with Hb Knossos/FSC8 mutation is compared, it is shown that the newly presented patient has a more severe condition, indicating that the mutations in the trans of Hb Knossos may play a role in the phenotypical expression of the disease