THIS WEEK
January 18, 2001
in the New England Journal of Medicine

"Prophylaxis against
P. carinii pneumonia
can be safely discontinued
in HIV-infected
patients who have
improved immunologic
function."
 
 graphic
Pneumocystis carinii		  
Discontinuation of Primary and Secondary Prophylaxis against Pneumocystis carinii Pneumonia
In this randomized trial, some patients with human immunodeficiency virus (HIV) infection discontinued either primary or secondary prophylaxis against Pneumocystis carinii pneumonia. All the patients had had a response to highly active antiretroviral therapy. After 19 months, no episodes of P. carinii pneumonia had occurred in the patients who discontinued primary or secondary prophylaxis.

 
Discontinuation of Secondary Prophylaxis against Pneumocystis carinii Pneumonia in HIV-Infected Patients
Many patients with HIV infection who have had P. carinii pneumonia have relapses unless they receive secondary prophylaxis against this infection. This study examined the effect of discontinuing secondary prophylaxis in patients who had had good responses to highly active antiretroviral therapy. Of 325 patients receiving antiretroviral therapy, none had recurrent P. carinii pneumonia during a median follow-up period of 13 months after the discontinuation of prophylaxis.

These studies, one randomized and one observational, add to the evidence from previous studies and show that prophylaxis against P. carinii pneumonia can be safely discontinued in patients with HIV who have responded to highly active antiretroviral treatment. Discontinuation of prophylactic treatment appears to be safe, after sufficient restoration of immunologic function, even in patients who have had an episode of pneumocystis pneumonia. However, prophylaxis must be resumed if the CD4 cell count declines to 200 per cubic millimeter or less.

Related Editorial


"The transplantation of
peripheral-blood cells
may offer advantages
over . . . bone marrow
in terms of overall
survival and disease-
free survival." 		Transplantation of Allogeneic Peripheral-Blood Cells or Bone Marrow in Patients with Hematologic Cancers
The classic means of rescuing the blood-forming system after high-dose chemotherapy involves the use of bone marrow as a source of hematopoietic stem cells. This study compared the transplantation of peripheral-blood cells with that of bone marrow cells, both from HLA-identical relatives, in patients who had been treated with high-dose chemotherapy. Peripheral-blood cells were just as efficient as bone marrow cells in restoring blood formation and did not significantly increase the risk of graft-versus-host disease.

The demonstration that hematopoietic stem cells circulate in the blood prompted the use of peripheral-blood cells for hematopoietic rescue. Excellent results with autologous blood cells have been reported, and now this study shows that allogeneic peripheral-blood cells can also restore hematopoiesis efficiently.


graphic 		Enzyme-Replacement Therapy in Mucopolysaccharidosis I
Mucopolysaccharidosis I is a lysosomal storage disease caused by a deficiency of (alpha)-L-iduronidase. It results in poor growth, mental retardation, cardiopulmonary and joint problems, and hepatosplenomegaly. Ten patients were treated with recombinant (alpha)-L-iduronidase, which resulted in improved joint mobility, cardiac function, and growth (in children); decreases in the size of the liver and spleen; and a decreased frequency of nocturnal apnea and hypopnea.

Many patients with mucopolysaccharidosis I die by their 20s. The only effective treatment has been bone marrow transplantation. Given the efficacy of (alpha)-L-iduronidase­replacement therapy, treatment for longer periods and at an earlier stage of the disease would seem appropriate.


"Molecular subtyping
of salmonella has been
used to distinguish
between outbreak-
associated infections and
sporadic infections." 		Improved Surveillance for Salmonella
It can be difficult to detect clusters or outbreaks of salmonellosis. In 1994, routine subtyping was instituted in Minnesota for all isolates of Salmonella enterica serotype typhimurium submitted to the Department of Health. During a five-year period, 16 outbreaks with a common source were identified. There were six larger outbreaks, of which four probably would not have been detected without molecular subtyping.

Routine rapid molecular subtyping of isolates is a way to enhance public health surveillance for food-borne pathogens. Molecular subtyping can help identify outbreaks early, but it depends on prompt submission of isolates to the state laboratory.


"The growth of managed
health care has not
been associated with a
reduction in the length
of office visits." 		Are Patients' Office Visits with Physicians Getting Shorter?
This study analyzed data from two national surveys to examine changes from 1989 to 1998 in the length of office visits to physicians. In neither data set was there evidence of a trend toward shorter office visits. In fact, the duration of office visits appears to have increased slightly for both visits covered by prepaid health plans and non-prepaid visits.

It is widely believed that managed care is reducing the time that physicians can spend with patients, but this analysis of data from a 10-year period shows that office visits have not gotten shorter and may actually be a bit longer. The discrepancy may derive from physicians' frustrations with the health care system.

Related Editorial

Primary Care: Acute Pharyngitis
Pharyngitis is one of the most common reasons for office visits. The causes include group A and non-group A streptococci, diphtheria, and Mycoplasma pneumoniae, as well as rhinovirus, coronavirus, Epstein-Barr virus, and even human immunodeficiency virus type 1. This review summarizes the use of diagnostic tests and the appropriate prescribing of antimicrobial drugs for the treatment of pharyngitis.