Cryptosporidium gastroenteritis in Egyptian children with acute lymphoblastic leukemia: magnitude of the problem.

PURPOSE: Cryptosporidium species is considered to be an important cause of significant morbidity in immunocompromised individuals. A prospective case-control study of sporadic diarrhea due to Cryptosporidium infection was conducted on children with acute lymphoblastic leukemia (ALL).
METHODS: Forty children with ALL on maintenance chemotherapy according to the Berlin-Frankfurt-Munster (BFM-90) protocol and 45 sex- and age-matched controls were studied. The ALL group included 25 patients with acute diarrhea and 15 without diarrhea, and the control group included 30 children with acute diarrhea and 15 without. Collected stool specimens were examined using modified Ziehl-Neelsen (MZN) and modified trichrome stains. Serum Cryptosporidium Parvum immunoglobulin G (IgG) antibodies were detected by enzyme-linked immunosorbent assay.
RESULTS: Cryptosporidium oocysts, pathogenic Gram-negative organisms, Giardia lamblia, and Entamoeba histolytica were identified in the stool samples (fecal specimens) of six (24%), eight (32%), four (16%), and two (8%), respectively, of the 25 patients with ALL and actute diarrhea and in one (3%), two (6.5%), six (20%), and five (16.5%), respectively, of the 30 control patients with diarrhea. Serum IgG antibodies were positive in four of the six ALL patients and in one of the control group patients with Cryptosporidium diarrhea who tested positive for oocysts in the stool. Diarrhea duration and severity were greater in ALL patients with stool-positive Cryptosporidium oocysts than in those with non-Cryptosporidium-positive diarrhea (p < 0.000).
CONCLUSIONS: Cryptosporidium infection should be considered in children with ALL presenting with prolonged or severe watery diarrhea during chemotherapy, especially those treated with methotrexate and 6-mercaptopurine. Since Cryptosporidium is not routinely tested for in stool examination, a MZN stain is recommended.