`ANGEL LOOKING OVER' AILING BOY; BONE MARROW DONOR EMERGES FOR THOUSAND OAKS 3-YEAR-OLD.

Byline: Kevin F. Sherry Daily News Staff Writer

For Christmas, 3-year-old Steven Koss is going to be given the gift of life.

An anonymous donor has agreed to provide the bone marrow that Steven needs for a transplant, his only hope of overcoming the aplastic anemia that has robbed his body of the ability to produce blood cells and platelets.

``I feel like there's an angel looking over him,'' his father, Scott Koss, said Thursday, the day after learning that one of three compatible donors listed on a national registry had agreed to the painful procedure.

``I guess the donor they found is really willing to do it,'' said Koss, who owns a landscaping company in Thousand Oaks. ``I think it's unbelievable that they're going to do it around Christmastime.''

This weekend will be the last that Steven will spend at home for the next month or so. He will be admitted Monday to UCLA Medical Center, where he will undergo radiation and chemotherapy to destroy his own bone marrow, thus reducing the chance that his body will reject the donor marrow.

Until Monday, Koss said, he plans to ``spend 24 hours a day with (Steven), because after that he's probably going to be sick.''

Steven faces a hospital stay of three to six weeks, depending on how he responds to the treatment and transplant, said Dr. Madeline Marcus, a fellow in pediatric hematology and oncology at UCLA and one of the youngster's physicians.

After the transplant, scheduled for Dec. 22, doctors will monitor Steven for infection and signs of rejection, she said. Doctors also will implant a chest catheter so they can draw blood and administer medication without having to stick him with a needle each time.

``He's tired of getting poked,'' Koss said.

Steven was upset when he heard the news of his impending hospital stay, said his mother, Shannon Smith. In fact, even she became upset when she learned that the long-sought transplant would take place.

``I cried,'' Smith said. ``It's a mixed emotion. I know it needs to be done - but I'm scared.''

But Smith and Koss realize the difference the procedure will make in their son's life. They have assured Steven that once he leaves the hospital, he will be able to play outside and have friends - something that has been impossible until now because of the threat of injury and infection.

``He hasn't even been outside to play on the grass at all,'' Koss said.

Doctors had hoped to be able to transplant marrow from Steven's 6-month-old sister, Serena, until a last-minute genetic test reveled that she is not a suitable match. Her marrow matched her brother on only three of six key genetic markers, while the anonymous donor is compatible in each instance.

The donor apparently thought that some discomfort and a short hospital stay around the holidays would be a small sacrifice to save a life, Marcus said.

``It really is a chance to affect and change somebody's life,'' Marcus said. ``At this time of year people are always thinking about giving, and there's no better gift you can give than the gift of life.''

Steven's family has no idea as to the identity of the donor, nor does that person know that his or her marrow will be going to the towheaded boy. Registry rules prevent patients and donors from knowing anything about each other until one year after the transplant takes place.

But Steven's mother already knows what she is going to say when she finally meets her son's donor.

``I can't wait until a year from now to say thank you so much,'' Smith said. ``I'm just so thankful they're giving our son a chance to live.''

Thousands need transplants

While Steven Koss' family was heartened by a public outpouring of support for their son, they and health officials fear that interest in bone marrow transplants will decline now that his search for a compatible donor is over.

``Most of us are motivated by that kind of story,'' said Pat Conlee, assistant director of the Marrow Donor Program for the American Red Cross of Los Angeles. ``The truth is that, unfortunately, at any one time there are about 4,000 people that are looking for a marrow transplant.''

Marrow transplants aid people with a variety of ailments, including leukemia, aplastic anemia and a score of blood-related illnesses.

In the San Fernando Valley and other parts of Los Angeles, residents can call the American Red Cross Donor Program at [phone], Ext. 5595, to find out when the next marrow registration drive will take place. Ventura County residents can call Children For Tomorrow at [phone].

Businesses or individuals who want to sponsor a tax-deductible marrow drive also can call the above numbers.

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Photo, box

PHOTO (color in Conejo and Simi edition only) Steven Koss, 3, will spend the holiday season in UCLA Medical Center, where he will receive a bone marrow transplant Dec. 22.

BOX: Thousands need transplants (see text)