Jorge Arellano

HLA antigens associated to amoebic abscess of the liver in Mexican mestizos

Summary Worldwide prevalence of amoebiasis is estimated at 4 ± 108 cases/year, yet only one of about 300 individuals harbouring Entamoeba histolytica suffers tissue invasion and these cases are mostly concentrated in certain areas of Asia, Africa and Latin America. Patients with amoebic abscess of the liver (AAL) represent only a small fraction of that. These contrasting figures have been tentatively explained on the one hand through variations in sex, immunocompetence. nutritional and other socioeconomic features of the host, and on the other hand through differences in parasite virulence. In order to explore a possible association between the major histocompatibility complex (MHC) and AAL susceptibility, we studied the HLA profile in 31 Mexican mestizos with AAL and compared it to race and socioeconomically matched controls. Mexican mestizo patients with AAL revealed a significant increase in HLA‐Bw16 and HLA‐DR3 which could suggest an HLA‐related susceptibility to liver invasion by E. histolytica.

Serum IgD concentration in pregnant women.

Abstract IgD levels were determined in maternal sera (obtained at delivery) at different stages of gestation, and found to be low in premature deliveries but normal in term deliveries when compared to those of normal nonpregnant women. Maternal IgD levels at delivery revealed a significant exponential correlation with duration of pregnancy. These results are at variance with the results of other surveys. The discrepancy could be explained on ethnic or methodological grounds. No correlation was found between maternal IgD levels and the degree of HL-A disparity between mother and product. Specificities HL-A-2 and HL-A-13 in the mother revealed a discrete correlation with IgD levels at delivery.

Further characterization of a human monocyte locomotion inhibitory factor produced by axenically grownEntamoeba histolytica

The present paper reports on a reevaluation of the thermostability of a partially purified MP locomotion inhibitory factor (MLIF), its preparation from washed and lysed amebas, and its recovery after absorption to MP

Increased susceptibility to experimental amebic abscess of the liver (EAAL) in gerbils (Meriones unguiculatus) with induced eosinopenia.

Normal human eosinophils—the same as neutrophils and mononuclear phagocytes—are killed in vitro by trophozoites of virulent Entamoeba histolytica , the parasite emerging unscathed from the event (1). However, if eosinophils are activated beforehand, the amebas are destroyed even if the leukocytes themselves eventually succumb in the process as well (2). Eosinophils, regularly present in the early inflammatory reaction of experimental amebic abscess of the liver (EAAL), are in strikingly close contact with the invading parasite (3), and because gerbils (Meriones unguiculatus) with induced eosinophilia are more resistant to EAAL than their normal counterparts (4), we explored further the role played by the eosinophil in invasive amebiasis by studying the course of EAAL in gerbils with induced eosinopenia.

Amebic lectin stimulation of lymphocytes of Mexican Mestizos recovered from amebic abscess of the liver induces decreased production of IL5 and IL6.

Th1-dependent cellular immunoinflammatory responses are claimed to be primarily involved in the progress and eventual outcome of invasive amebiasis [i.e., amebic abscess of the liver (AAL)] (1). Th1 cells control mostly cell-mediated immune responses, and the resulting inflammatory reaction through the production of IL2, IFNg , TNFa , etc., while Th2 cells are mainly involved in humoral antibody immunity and eosinophilia through the production of IL4, IL5, IL6, IL10, etc. (2). We explored whether the risk to develop AAL could be related to a particular, possibly inherited (HLA-DR3-related?) (3), pattern of Th1 or Th2 cytokine response in the host. We, therefore, measured the production of Th1 (IL2, INFg , and TNFa ) and Th2 (IL4, IL5, and IL6) cytokines in lymphocytes of healthy adult Mexican mestizos who had long before recovered from AAL, and compared it to Mexican mestizo healthy controls.

Induction of protective immunity against experimental amebic abscess of the liver (EAAL) using the monocyte locomotion inhibitory factor (MLIF) produced by Entamoeba histolytica: a preliminary report.

MLIF is an anti-inflammatory oligopeptide produced by Entamoeba histolytica in axenic cultures that among other effects inhibits the locomotion of human peripheral blood monocytes [hence, its name, monocyte locomotion inhibitory factor (MLIF)]. This factor may contribute to the paucity of the late inflammatory reaction found in invasive amebiasis, but this, in turn, may allow for the perfect regeneration of the affected organs (liver, skin) observed upon successful treatment (1). In any event, however, we do not yet know whether E. histolytica actually uses—or even produces—MLIF in vivo. If it does, MLIF may be an evasion factor of the ameba against the inflammatory defenses of the host. We, therefore, attemped to induce protective immunity against experimental amebic abscess of the liver (EAAL) by using a MLIF-KLH complex as an immunogen (2).