Gene frequencies of the HPA-1 to -6 and -15 human platelet antigens in Tunisian blood donors.

Gene frequencies of mainly human platelet antigens (HPA) -1 to -6 and -15 were determined in 116 Tunisian blood donors. The distribution of HPA-1, -3 and -5 systems approach those found in other Maghrebian populations. Tunisians have the highest frequency of HPA-1b and -5b alleles. The distribution of HPA-1a allele and HPA-4, -6 and -15 systems is similar to Caucasians. Phylogenetic study using the neighbor-joining method and principal component multivariate analysis demonstrate that Tunisians are more closely related to western than to eastern Mediterraneans. This immunogenetic study highlights the relatedness between Mediterranean populations and will serve as a baseline study for future clinical research involving platelet disorders among Tunisians.

Platelet-specific alloantigens and antibodies in Tunisian women after three or more pregnancies.

Pregnancy may allow alloimmunization against human platelet antigens (HPA), which can lead to neonatal alloimmune thrombocytopenia (NAIT). The specificities of alloantibodies are closely related to the distribution of the HPA systems. A total of 281 Tunisian multiparous women (mean number of pregnancies: 4.5) were phenotyped for the HPA-1, -3 and -5 systems, by monoclonal antibody immobilization of platelet antigens (MAIPA). We searched for antibodies against HPA-1a, HPA-3a, HPA-5b and HPA-5a in HPA-1b1b, HPA-3b3b, HPA-5a5a and HPA-5b5b individuals, respectively. The gene frequencies were: 0.83 for HPA-1a, 0.17 for HPA-1b, 0.78 for HPA-3a, 0.22 for HPA-3b, 0.82 for HPA-5a and 0.18 for HPA-5b. Anti-HPA-5b antibodies were present in eight sera and anti-HPA-3a antibodies were present in one serum. The anti-HPA-5b system is the most frequently involved in platelet alloimmunization in Tunisian multiparous women. However, prospective trials are required to confirm this result and to determine the exact frequencies and clinical relevance of platelet alloantibodies in pregnant Tunisian women.

Antibodies to anionic phospholipids and cofactors in kala-azar. Comparative study with malaria, toxoplasmosis and "autoimmune diseases".

OBJECTIVE: To investigate the distribution of various anti-anionic and anti-cofactor phospholipid antibodies in children with kala-azar, and to compare them to malaria, toxoplasmosis and auto-immune disease. PATIENTS AND METHODS: The frequency and the concentration of antibodies against cardiolipin (aCL), phosphatidylserine (aPS), phosphatidylinositol (aPI), phosphatidic acid (aPA), Beta2GPI (anti-Beta2GPI), prothrombin (aPT), annexin V (aAnnV), protein C (aPnC) and protein S (aPnS) were studied in sera from 103 children with kala-azar and compared with malaria (n=32), toxoplasmosis (n=31), systemic lupus erythematosus (SLE) (n=40) and antiphospholipid syndrome (APS) (n=35). RESULTS: The prevalence of aCL, aPS, aPI, aPA, anti-Beta2GPI, aPT, aAnnV, aPnC and aPnS was 54%, 56%, 43%, 28%, 73%, 67%, 55%, 30%, 25%, respectively. Ninety-three per cent of children with kala-azar (96/103) had one or more aPL specificities, but none had thromboses. The spectrum of aPL was quite similar to that found in patients with SLE and APS. CONCLUSION: Antiphospholipid antibodies are a frequent finding in kala-azar. The aPL produced mimic those found in autoimmune disease. However, further studies are required to assess the exact role of these aPL during leishmaniasis.

[Xg gene frequencies in Tunisia]. / Fréquence génique du système Xg dans la population tunisienne.

We report a new case of anti-Xg(a) antibody found in a man who, after receiving six units of standard red blood cells, developed a minor nonhemolytic transfusion reaction (chills-hyperthermia). The patient sera was used for an immunophenotyping scale in 777 healthy Tunisian blood donors (678 men; 99 women). The phenotype frequencies of Xg(a+) and Xg(a-) were 67.4% and 32.6% in men and 89 and 11% in women, respectively. The gene frequencies of Xg(a) and Xg were 0.67 and 0.33, respectively. These frequencies are similar to that reported in predominantly white populations.