Low-grade parasitaemias and cold agglutinins in patients with hyper-reactive malarious splenomegaly and acute haemolysis

R.J. Torres, L Villegas, D. H. Campora Perez, L.F. Flores-Suarez, M A Torres V, M Campos

Research output: Contribution to JournalArticleAcademicpeer-review


A cluster of 16 cases of hyper-reactive malarious splenomegaly (HMS) with severe, acute haemolysis, from an isolated, Venezuelan, Yanomami population, was prospectively investigated. Nine (69%) of the 13 HMS sera investigated but only one (7%) of 14 control sera (P < 0.005) contained elevated titres (of at least 1:32) of complement-fixing IgM cold agglutinins (CA). The CA detected had specificity for both the I and i blood-group antigens (with a relative predominance of anti-I) and wide thermal stability. The mean reciprocal CA titre was much higher for the HMS sera than for the control samples (59.16 v. 2.28; P < 0.001). Indirect tests for antiglobulin were positive for two of the 13 HMS cases (but none of 14 controls) investigated; all of the direct tests for antiglobulin gave negative results. The seven HMS cases checked, using an assay based on a nested PCR which amplified species-specific ribosomal sequences from Plasmodium vivax or P. falciparum, each yielded the PCR product that indicated P. vivax infection. However, only six (25%) of the 24 control samples (collected, at the same time as the HMS samples, from asymptomatic adults from the same Yanomami population) were PCR-positive (P < 0.001). In some cases at least, the acute severe episodes of haemolysis occasionally seen in HMS appear to be associated with an auto-immune, cold-agglutinin-mediated response triggered by non-patent parasitaemias.

Original languageEnglish
Pages (from-to)125-30
Number of pages6
JournalAnnals of Tropical Medicine and Parasitology
Issue number2
Publication statusPublished - Mar 2003


  • Adult
  • Agglutinins
  • Animals
  • Antibodies, Protozoan
  • Autoantibodies
  • Cluster Analysis
  • Cryoglobulins
  • Disease Outbreaks
  • Electrophoresis, Polyacrylamide Gel
  • Hemolysis
  • Humans
  • Immunologic Tests
  • Indians, South American
  • Malaria
  • Parasitemia
  • Plasmodium falciparum
  • Plasmodium vivax
  • Polymerase Chain Reaction
  • Prospective Studies
  • RNA, Protozoan
  • Splenomegaly
  • Journal Article
  • Research Support, Non-U.S. Gov't


Dive into the research topics of 'Low-grade parasitaemias and cold agglutinins in patients with hyper-reactive malarious splenomegaly and acute haemolysis'. Together they form a unique fingerprint.

Cite this